Name: 672292-97-6
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SKU: A296210
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Quality Control of [ 672292-97-6 ] Purity: 95% SDS Specification

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Product Details of [ 672292-97-6 ]

CAS No. :	672292-97-6
Formula :	C₁₀H₉ClINO₃
M.W :	353.54
SMILES Code :	O=C(OC)C1=CC(I)=C(NC(C)=O)C=C1Cl
English Name :	Methyl 4-acetamido-2-chloro-5-iodobenzoate
MDL No. :	MFCD09260862
InChI Key :	CIGRRTUPLGBKEU-UHFFFAOYSA-N
Pubchem ID :	11839202

Safety of [ 672292-97-6 ]

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Computational Chemistry of [ 672292-97-6 ] Show Less

Physicochemical Properties

Num. heavy atoms	16
Num. arom. heavy atoms	6
Fraction Csp3	0.2
Num. rotatable bonds	4
Num. H-bond acceptors	3.0
Num. H-bond donors	1.0
Molar Refractivity	69.76
TPSA ? Topological Polar Surface Area: Calculated from Ertl P. et al. 2000 J. Med. Chem.	55.4 Å²

Lipophilicity

Log P_o/w (iLOGP)? iLOGP: in-house physics-based method implemented from Daina A et al. 2014 J. Chem. Inf. Model.	2.51
Log P_o/w (XLOGP3)? XLOGP3: Atomistic and knowledge-based method calculated by XLOGP program, version 3.2.2, courtesy of CCBG, Shanghai Institute of Organic Chemistry	2.23
Log P_o/w (WLOGP)? WLOGP: Atomistic method implemented from Wildman SA and Crippen GM. 1999 J. Chem. Inf. Model.	2.5
Log P_o/w (MLOGP)? MLOGP: Topological method implemented from Moriguchi I. et al. 1992 Chem. Pharm. Bull. Moriguchi I. et al. 1994 Chem. Pharm. Bull. Lipinski PA. et al. 2001 Adv. Drug. Deliv. Rev.	2.79
Log P_o/w (SILICOS-IT)? SILICOS-IT: Hybrid fragmental/topological method calculated by FILTER-IT program, version 1.0.2, courtesy of SILICOS-IT, http://www.silicos-it.com	2.95
Consensus Log P_o/w? Consensus Log P_o/w: Average of all five predictions	2.6

Water Solubility

Log S (ESOL):? ESOL: Topological method implemented from Delaney JS. 2004 J. Chem. Inf. Model.	-3.45
Solubility	0.125 mg/ml ; 0.000355 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	Soluble
Log S (Ali)? Ali: Topological method implemented from Ali J. et al. 2012 J. Chem. Inf. Model.	-3.03
Solubility	0.331 mg/ml ; 0.000936 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	Soluble
Log S (SILICOS-IT)? SILICOS-IT: Fragmental method calculated by FILTER-IT program, version 1.0.2, courtesy of SILICOS-IT, http://www.silicos-it.com	-4.39
Solubility	0.0145 mg/ml ; 0.0000411 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	Moderately soluble

Pharmacokinetics

GI absorption? Gatrointestinal absorption: according to the white of the BOILED-Egg	High
BBB permeant? BBB permeation: according to the yolk of the BOILED-Egg	Yes
P-gp substrate? P-glycoprotein substrate: SVM model built on 1033 molecules (training set) and tested on 415 molecules (test set) 10-fold CV: ACC=0.72 / AUC=0.77 External: ACC=0.88 / AUC=0.94	No
CYP1A2 inhibitor? Cytochrome P450 1A2 inhibitor: SVM model built on 9145 molecules (training set) and tested on 3000 molecules (test set) 10-fold CV: ACC=0.83 / AUC=0.90 External: ACC=0.84 / AUC=0.91	Yes
CYP2C19 inhibitor? Cytochrome P450 2C19 inhibitor: SVM model built on 9272 molecules (training set) and tested on 3000 molecules (test set) 10-fold CV: ACC=0.80 / AUC=0.86 External: ACC=0.80 / AUC=0.87	Yes
CYP2C9 inhibitor? Cytochrome P450 2C9 inhibitor: SVM model built on 5940 molecules (training set) and tested on 2075 molecules (test set) 10-fold CV: ACC=0.78 / AUC=0.85 External: ACC=0.71 / AUC=0.81	No
CYP2D6 inhibitor? Cytochrome P450 2D6 inhibitor: SVM model built on 3664 molecules (training set) and tested on 1068 molecules (test set) 10-fold CV: ACC=0.79 / AUC=0.85 External: ACC=0.81 / AUC=0.87	No
CYP3A4 inhibitor? Cytochrome P450 3A4 inhibitor: SVM model built on 7518 molecules (training set) and tested on 2579 molecules (test set) 10-fold CV: ACC=0.77 / AUC=0.85 External: ACC=0.78 / AUC=0.86	No
Log Kp (skin permeation)? Skin permeation: QSPR model implemented from Potts RO and Guy RH. 1992 Pharm. Res.	-6.87 cm/s

Druglikeness

Lipinski? Lipinski (Pfizer) filter: implemented from Lipinski CA. et al. 2001 Adv. Drug Deliv. Rev. MW ≤ 500 MLOGP ≤ 4.15 N or O ≤ 10 NH or OH ≤ 5	0.0
Ghose? Ghose filter: implemented from Ghose AK. et al. 1999 J. Comb. Chem. 160 ≤ MW ≤ 480 -0.4 ≤ WLOGP ≤ 5.6 40 ≤ MR ≤ 130 20 ≤ atoms ≤ 70	None
Veber? Veber (GSK) filter: implemented from Veber DF. et al. 2002 J. Med. Chem. Rotatable bonds ≤ 10 TPSA ≤ 140	0.0
Egan? Egan (Pharmacia) filter: implemented from Egan WJ. et al. 2000 J. Med. Chem. WLOGP ≤ 5.88 TPSA ≤ 131.6	0.0
Muegge? Muegge (Bayer) filter: implemented from Muegge I. et al. 2001 J. Med. Chem. 200 ≤ MW ≤ 600 -2 ≤ XLOGP ≤ 5 TPSA ≤ 150 Num. rings ≤ 7 Num. carbon > 4 Num. heteroatoms > 1 Num. rotatable bonds ≤ 15 H-bond acc. ≤ 10 H-bond don. ≤ 5	0.0
Bioavailability Score? Abbott Bioavailability Score: Probability of F > 10% in rat implemented from Martin YC. 2005 J. Med. Chem.	0.55

Medicinal Chemistry

PAINS? Pan Assay Interference Structures: implemented from Baell JB. & Holloway GA. 2010 J. Med. Chem.	0.0 alert
Brenk? Structural Alert: implemented from Brenk R. et al. 2008 ChemMedChem	1.0 alert: heavy_metal
Leadlikeness? Leadlikeness: implemented from Teague SJ. 1999 Angew. Chem. Int. Ed. 250 ≤ MW ≤ 350 XLOGP ≤ 3.5 Num. rotatable bonds ≤ 7	No; 1 violation:MW<1.0
Synthetic accessibility? Synthetic accessibility score: from 1 (very easy) to 10 (very difficult) based on 1024 fragmental contributions (FP2) modulated by size and complexity penaties, trained on 12'782'590 molecules and tested on 40 external molecules (r² = 0.94)	1.98

Application In Synthesis of [ 672292-97-6 ]

* All experimental methods are cited from the reference, please refer to the original source for details. We do not guarantee the accuracy of the content in the reference.

Downstream synthetic route of [ 672292-97-6 ]

[ 672292-97-6 ] Synthesis Path-Downstream 1~8

1
[ 256935-85-0 ]
[ 75-36-5 ]
[ 672292-97-6 ]

Yield	Reaction Conditions	Operation in experiment
81%	With pyridine In tetrahydrofuran at 0℃; for 4h;	3.B To a solution of 4-amino-5-iodo-2-chloro-benzoic acid methyl ester (104 g, 330 mmol) in 330 mL THF was added pyridine (40 mL). The solution was cooled to 0° C. and acetyl chloride (35 mL) was added slowly. Stirring was continued for 4 h. The mix was cooled and H2O (800 mL) was added dropwise. Filtered and washed with H2O followed by MeOH/H2O (1:1). Upon drying, the product was obtained in 81% yield. M+H+(354).
78%	With pyridine In tetrahydrofuran at 10 - 30℃; for 4h; Industry scale;	1; 4 Example 1 Synthesis of 2-Chloro-4-acetamido-5-iodobenzoic Acid Methyl Ester[0058] The methyl ester of 2-chloro-4-amino-5-iodobenzoic acid (ca. 362 kg) was mixed with tetrahydrofuran (THF: 826 kg) and stirred. Pyridine (138 kg) and more THF (92 kg) were added, and the mixture was cooled to 10-200C. Acetyl chloride (119 kg) was added at a rate that permitted the temperature to be maintained below 250C; THF (92 kg) was used to rinse the acetyl chloride into the reaction vessel. The reaction mixture was stirred for 4 hours or until at least 97% consumption of starting material was achieved as judged by HPLC analysis.[0059] The mixture was cooled to 10-150C, and water (2520 L) was added in 3 batches, while the temperature was maintained at 10-250C. The solids were then collected by processing the mixture in five batches with a centrifuge: each batch was washed with water (91 L), water (91 L), and methanol (91 L). After this, each batch was suspended in methanol (2500 L) and refluxed for one hour, and was then cooled to 0-5 0C. Product was collected by centrifugation and dried at 35-45 0C. If analysis of a batch shows a significant amount of the regioisomeric iodide or the diiodide carried through from the iodination step (e.g., if the product constitutes less than about 93% of the material detected by HPLC), the solids may be slurried with cold methanol and re-centrifuged to remove much of those impurities.[0060] Repeating this reaction at about this scale several times provided a reproducible yield of 78-81%, and the product wasan off-white to light brown or light pink solid that was 97-99% homogenous by HPLC.; Example 4Stage 3 Stage 3 aC8H7ClINO2 C10H9CIINO3 F. W. 311.50 F.W. 353.54 SCI-0216433 SCI-0216434[0071] The Stage 3a process has undergone a number of changes since Campaign S2. These are summarised briefly below:[0072] For Campaigns S2 and S3, an optional methanol re-slurry was included in the Stage 3 a process, dependent on the HPLC purity of the crude wet-cake. If the wet-cake purity was below 93 area % then the re-slurry was performed. This was the case for both S2 and S3 and it was decided that the re-slurry should be made mandatory for S4 for the sake of process consistency. In the event, the crude Stage 3 a product was much purer than in previous campaigns (97.6 area %) and the re-slurry upgraded it to 99.9 area %. Mass balance studies indicated that the re-slurry resulted in a yield loss of around 5 %.[0073] For Campaign S5, the Stage 3a process was transferred to the RPS Dudley One Semi-works facility. The batch size (Stage 3 input) was increased by a factor of 2.3 from 127 to 292 kg. Isolation of the product was carried out using a peeler centrifuge in place of the ceramic vat-filter employed in the Pilot Campaigns.[0074] As the S5 product was to be isolated on a centrifuge, it was anticipated that the crude material would have a greater purity than that seen in earlier campaigns and that the methanol re-slurry would therefore not be required. This proved to be the case and all the crude wet-cake from both batches was found to have purity in excess of 93 area %. In P A T E N T Attorney Docket: SCI5249WOPCT fact, eight out often of the centrifuge baskets had purities greater than 98 %. Centrifugation was clearly more efficient at liquor removal than vat-filtration.[0075] The batch size (Stage 3a input) for Campaign S6 was increased by a factor of 1.31 from 292 to 382 kg. The only other change was the incorporation of additional cold methanol centrifuge washes for one of the batches, which had an abnormally high regioisomer content in the Stage 3 input. This strategy proved successful as the regioisomer content was reduced from as high as 12.9 area % in the Stage 3 input to less than 1 area % in the Stage 3 a product.Comparison of Yield and Purity for Campaigns S3 to S6.[0076] Table One gives a comparison of yield and purity data for Campaigns S3 to S6.Table One: Stage 3a Yield and Purity Data for Campaigns S3 to S6[0077] The assay-based yields have remained fairly constant across the four campaigns S3 to S6. Laboratory experiments indicate that yields in excess of 90 % should be achieved in the P A T E N T Attorney Docket: SCI5249WOPCT αu&cuι.c ui me meuianoi re-smrry. campaigns S3 and S4 both incorporated the re-slurry, which was undoubtedly the main reason for the low yields observed.[0078] Surprisingly, no improvement in yield was seen in S5, which did not incorporate the re- slurry. Due to the relatively high minimum stir volume in the reaction vessel V3166, it proved necessary to charge additional THF (29 % of original charge) in order to achieve efficient agitation. Although the water quench charge was increased by the same proportion, this change resulted in the Stage 3 a product being isolated from a significantly increased solvent volume. This is probably the main reason for the yield short-fall in S5. However, analysis of the mother liquors did not indicate the presence of significant amounts of product. It has since been shown that the assay method underestimates the amount of Stage 3a present when applied to solutions. In future, liquor samples should be concentrated to dryness before attempting to perform an assay.[0079] The S6 yield was even more disappointing than that obtained in S5. There are two principle reasons for this:[0080] The Stage 3 input for the second batch had an abnormally high level of the regioisomeric impurity (up to 12.9 area %). In order to remove this, additional cold methanol washes were applied during centrifugation of the Stage 3 a product. These proved highly effective in removing the impurity, but undoubtedly had a detrimental effect on yield.[0081] For batch 80012941, additional THF had to be charged in order to mobilise solids remaining in vessel V3166 after transfer of the main batch to VlOOl. The solids were successfully mobilised, but it was necessary to charge additional water as an anti-solvent to compensate for the extra THF. In spite of the additional water charge, it is likely that this deviation will have resulted in some loss of product to the liquors.[0082] To prevent a repetition of the losses observed in S5 and S6, the following measures are proposed or have already been implemented:[0083] Particular attention should be paid to isolation of the Stage 3 product on the centrifuge. Efficient de-liquoring at this point is essential to removing the unwanted regioisomer and thereby avoiding the need for additional methanol washes at Stage 3 a.[0084] Larger agitator blades have been fitted to V3166. The resulting improved agitation should avoid the need to charge additional THF to the reaction mixture as in S5. [0085] The reaction mixture should be quenched with water in V3166 before transfer to VlOOl . This should avoid the problems associated with solids settling out in V3166 during the transfer. Once quenched, the mixture is much more mobile and should be transferred more readily, P A T E N T Attorney Docket: SCI5249WOPCT luυsoj In addition to the above changes, an increased reaction concentration has now been demonstrated at Pilot scale. This will result in a significant improvement in volumetric efficiency and allow a larger batch size to be accommodated. Process Outline[0087] Below is the process outline of the Stage 3a process employed in Campaign S6. Process outlines for Campaigns S3, S4 and S5 are contained in the relevant campaign reports. P A T E N T Attorney Docket: SCI5249WOPCT P A T E N T Attorney Docket: SCI5249WOPCT P A T E N T Attorney Docket: SCI5249WOPCT P A T E N T Attorney Docket: SCI5249WOPCT[0088] Expected dry weight = 333 Kg (81 %)Equipment Train[0089] For Campaigns S3 and S4, Stage 3a manufacture, aqueous work-up and crystallisation were performed in PV351, a 300-gallon glass-lined vessel. The product was isolated in PD351 and PD404, ceramic vat-filters associated with PV351 and dried in PK602, a double cabinet air tray-dryer.[0090] Campaigns S5 and S6 were carried out in the RPS Dudley One Semi-works facility. The reaction chemistry took place in V3166, a 1000-gallon hastelloy reactor. The aqueous quench/crystallisation was performed in VlOOl, a 1000-gallon glass-lined vessel, and the product was isolated on D3353, a hastelloy peeler centrifuge. Drying took place in K3045, a stainless steel vacuum tray dryer.Quality-Critical Parameters[0091] No laboratory work to identify quality-critical parameters has been performed for Stage 3a. The product manufactured in Campaigns S3 to S6 has consistently satisfied specification and no quality-critical parameters have been identified from the processing records. P A T E N T Attorney Docket: SCI5249WOPCT[0092] The quality of the Stage 3a manufactured is largely determined by the quality of the Stage 3 input. In Campaign S3 and one batch of S6, relatively high levels of diiodo-Stage 3 were present in the Stage 3 input. This impurity was partially removed during the Stage 3 a process, but not completely. This is reflected in the low purities for the relevant batches shown in Table One. Clearly, good control over formation of the diiodo impurity at Stage 3 is essential to generating high purity Stage 3a.[0093] The other main impurity observed in Stage 3 a is the Stage 3 a regioisomer. This is the product of acetylation of the corresponding Stage 3 impurity. Efficient centrifugation of the Stage 3 product is the main requirement for controlling the level of this impurity. [0094] As indicated earlier, the Stage 3 a process includes provision for a methanol re-slurry if the wet-cake purity is below 93 area %. In reality, centrifugation results in high purity product and the re-slurry was employed in neither S5 nor S6.Parameters Affecting Yield[0095] In Campaigns S5 and S6, it proved necessary to charge additional THF to the process in order to achieve satisfactory slurry mobility. Although additional water (anti-solvent) was charged pro-rata to compensate for this, it seems likely that the additional solvent resulted in some yield losses. As described above, improved agitation and direct quenching of the batch in V3166 should remove the need for extra THF in future campaigns.[0096] The Stage 3 input for S6 batch 80012941A,B,C contained a high level of the Stage 3 regioisomer. This was acetylated to give the Stage 3a regioisomer and extra methanol centrifuge washes were applied to remove it from the product. These undoubtedly resulted in some yield loss. By ensuring efficient regioisomer removal at Stage 3, it should be possible to prevent such losses in future campaigns.[0097] Conversion of Stage 3 to Stage 3 a is monitored by HPLC analysis of the reaction mixture. Table Two gives a comparison of final in-process levels of Stage 3 and the Stage 3 content of the isolated Stage 3 a product. The current in-process limit for unreacted Stage 3 is 3 area % and this has remained unchanged since the process was introduced to the Dudley site in 2001. P A T E N T Attorney Docket: SCI5249WOPCTTable Two: Comparison of In-process and Intermediate Stage 3 levels for Stage 3a Campaigns S3 to S6[0098] The data in Table Two indicate that in-process levels of unreacted Stage 3 up to 2.5 area % are well tolerated by the process. The S6 batch 80012940 gave a final completion result of 2.5 area % Stage 3, but the batch still had less than 1.0 area % of Stage 3 in the isolated product. It would therefore seem that the unreacted starting material is efficiently removed during isolation. From an economic viewpoint, this represents significant lost yield. It is therefore recommended that the in-process limit be lowered to 1 area %. There should be no difficulty in achieving this level. In fact, the lower limit has already been employed successfully in the recent Pilot Trial.Table Three: Comparison of Stage 3a In-process and Intermediate HPLC Purities for CampaignsS3 to S6 P A T E N T Attorney Docket: SCI5249WOPCTa. Re-s urry performed, even though batch met in-process limit, for consistency with previous batches b. Values shown are simple averages for all centrifuge basket-loads c. Values shown are simple averages for all part-batches (A,B etc.) corresponding to oven charges[0099] All batches from Campaign S4 onwards have readily achieved the in-process limit and have therefore not required re-slurry. However, a re-slurry was employed for the S4 batch for the sake of consistency with earlier batches. The Stage 3a product isolated on the centrifuge in S5 and S6 had generally high purity (>98 area %). Batch 80012940 had atypically low purity (96.6 area %) on account of a high level of the diiodo impurity carried over from Stage 3. The high purity of batch 80012941 was ensured by employing additional methanol centrifuge washes to remove the regioisomeric impurity, which was present at high levels due to inefficient centrifugation of the Stage 3 input.[00100] With efficient centrifugation and good control over formation of the diiodo impurity at Stage 3, it should be possible to generate Stage 3a product with greater than 98 area % purity. Up to and including Campaign S6, the Stage 3a purity specification was set very low at 'NLT 85 area %'. It has since been tightened to 'NLT 94 area %'. The methanol re-slurry is known to be effective in upgrading the Stage 3a purity by removing the regioisomeric impurity and, to a lesser extent, the diiodo impurity. It would therefore be prudent to retain the in-process analysis, raising the limit to 'NLT 94 area %'. This would allow material which failed to meet the purity specification to be upgraded before drying.Table Four: Comparison of Stage 3a In-process and Intermediate LOD Values for Campaigns S3 to S6 P A T E N T Attorney Docket: SCI5249WOPCTa. In-process sample was composite of parts A and B[00101] Table Four shows good agreement between in-process and intermediate LOD values for Stage 3a. Based on this data, the current in-process limit is judged adequate to ensure that the intermediate specification (NMT 0.5 % w/w) is achieved.Stage 3a HPLC Profile[00102] Table Five shows the Stage 3a HPLC profiles for Campaigns S3 to S6. The overall purity has generally been greater than 94 area %. In fact, when good control over the regioisomer and diiodo impurities is achieved, purity values in excess of 98 area % have been consistently observed. The overall purity of the Stage 3 a product is less important than the levels of the individual impurities. For example, it is known that the diiodo impurity up to a level of 5.8 area % is removed at Stage 4. hi contrast, there is no data to support onward processing of such high levels of the Stage 3 a regioisomer.Stage 3 a Regioisomer[00103] This impurity is formed by acetylation of the 3-iodo regioisomer foϖned as a major side- product at Stage 3. The level of the impurity is therefore determined by the amount of the 3-iodo compound present in the Stage 3 input. This, in turn, is determined by the efficiency of liquor removal and washing on the centrifuge. Good centrifuge technique at Stage 3 is therefore essential to controlling this impurity. If the impurity is detected at high levels in the Stage 3 product, it can be removed by means of an isopropyl alcohol re-slurry. It can also be removed at Stage 3a, by re-slurrying the wet-cake in methanol. P A T E N T Attorney Docket: SCI5249WOPCTDiiodo Impurity[00104] This impurity is generated at Stage 3 as a result of over-iodination. As yet, there is no proven method for removing it, although the Stage 3a methanol re-slurry is partially effective. Levels up to 5.8 area % have been tolerated by the Stage 4 process (Campaign S3). It is thought that the impurity is converted to the bis(TMS acetylene) compound under the Stage 4 conditions and that this is removed during the crystallisation. The current specification is 'Report value'.RRTs 0.83 and 1.09[00105] These impurities have only been detected in two part-batches. Their identity is not known.'Table Five: Stage 3a HPLC Profiles for Campaigns S3 to S6
73.6%	With pyridine In tetrahydrofuran at 10 - 30℃; for 4h;	1; 4.4 EXAMPLE 1; Synthesis of 2-Chloro-4-acetamido-5-iodobenzoic Acid Methyl Ester; The methyl ester of 2-chloro-4-amino-5-iodobenzoic acid (ca. 362 kg) was mixed with tetrahydrofuran (THF: 826 kg) and stirred. Pyridine (138 kg) and more THF (92 kg) were added, and the mixture was cooled to 10-20° C. Acetyl chloride (119 kg) was added at a rate that permitted the temperature to be maintained below 25° C.; THF (92 kg) was used to rinse the acetyl chloride into the reaction vessel. The reaction mixture was stirred for 4 hours or until at least 97% consumption of starting material was achieved as judged by HPLC analysis. The mixture was cooled to 10-15° C., and water (2520 L) was added in 3 batches, while the temperature was maintained at 10-25° C. The solids were then collected by processing the mixture in five batches with a centrifuge: each batch was washed with water (91 L), water (91 L), and methanol (91 L). After this, each batch was suspended in methanol (2500 L) and refluxed for one hour, and was then cooled to 0-5° C. Product was collected by centrifugation and dried at 35-45° C. If analysis of a batch shows a significant amount of the regioisomeric iodide or the diiodide carried through from the iodination step (e.g., if the product constitutes less than about 93% of the material detected by HPLC), the solids may be slurried with cold methanol and re-centrifuged to remove much of those impurities. Repeating this reaction at about this scale several times provided a reproducible yield of 78-81%, and the product was an off-white to light brown or light pink solid that was 97-99% homogenous by HPLC.; EXAMPLE 4; The Stage 3a process has undergone a number of changes since Campaign S2. These are summarised briefly below: For Campaigns S2 and S3, an optional methanol re-slurry was included in the Stage 3a process, dependent on the HPLC purity of the crude wet-cake. If the wet-cake purity was below 93 area % then the re-slurry was performed. This was the case for both S2 and S3 and it was decided that the re-slurry should be made mandatory for S4 for the sake of process consistency. In the event, the crude Stage 3a product was much purer than in previous campaigns (97.6 area %) and the re-slurry upgraded it to 99.9 area %. Mass balance studies indicated that the re-slurry resulted in a yield loss of around 5%. For Campaign S5, the Stage 3a process was transferred to the RPS Dudley One Semi-works facility. The batch size (Stage 3 input) was increased by a factor of 2.3 from 127 to 292 kg. Isolation of the product was carried out using a peeler centrifuge in place of the ceramic vat-filter employed in the Pilot Campaigns. As the S5 product was to be isolated on a centrifuge, it was anticipated that the crude material would have a greater purity than that seen in earlier campaigns and that the methanol re-slurry would therefore not be required. This proved to be the case and all the crude wet-cake from both batches was found to have purity in excess of 93 area %. In fact, eight out of ten of the centrifuge baskets had purities greater than 98%. Centrifugation was clearly more efficient at liquor removal than vat-filtration. The batch size (Stage 3a input) for Campaign S6 was increased by a factor of 1.31 from 292 to 382 kg. The only other change was the incorporation of additional cold methanol centrifuge washes for one of the batches, which had an abnormally high regioisomer content in the Stage 3 input. This strategy proved successful as the regioisomer content was reduced from as high as 12.9 area % in the Stage 3 input to less than 1 area % in the Stage 3a product. Comparison of Yield and Purity for Campaigns S3 to S6. Table One gives a comparison of yield and purity data for Campaigns S3 to S6. TABLE ONE Stage 3a Yield and Purity Data for Campaigns S3 to S6 Camp'n Stage 3a Camp'n Assay- HPLC Stage 3a Physical based Purity Stage 3a Batch Stage 3 Input Output Yield Yield (Area Campaign Number (kg) (kg) (%) (%) %) S3 80009407A, B 122.7 102.5 73.6 Data not 94.4 available S4 80010873A, B 127.0 114.7 79.6 83.8 99.9 S5 80012347A, B 291.9 274.1 80.8 82.4 99.1 80012348A, B, C 291.9 261.2 98.7 S6 80012940A, B, C 374.0 343.6 78.0 81.6 96.6 80012941A, B, C 391.0 333.8 99.0 The assay-based yields have remained fairly constant across the four campaigns S3 to S6. Laboratory experiments indicate that yields in excess of 90% should be achieved in the absence of the methanol re-slurry. Campaigns S3 and S4 both incorporated the re-slurry, which was undoubtedly the main reason for the low yields observed. Surprisingly, no improvement in yield was seen in S5, which did not incorporate the re-slurry. Due to the relatively high minimum stir volume in the reaction vessel V3166, it proved necessary to charge additional THF (29% of original charge) in order to achieve efficient agitation. Although the water quench charge was increased by the same proportion, this change resulted in the Stage 3a product being isolated from a significantly increased solvent volume. This is probably the main reason for the yield short-fall in S5. However, analysis of the mother liquors did not indicate the presence of significant amounts of product. It has since been shown that the assay method underestimates the amount of Stage 3a present when applied to solutions. In future, liquor samples should be concentrated to dryness before attempting to perform an assay. The S6 yield was even more disappointing than that obtained in S5. There are two principle reasons for this: The Stage 3 input for the second batch had an abnormally high level of the regioisomeric impurity (up to 12.9 area %). In order to remove this, additional cold methanol washes were applied during centrifugation of the Stage 3a product. These proved highly effective in removing the impurity, but undoubtedly had a detrimental effect on yield. For batch 80012941, additional THF had to be charged in order to mobilise solids remaining in vessel V3166 after transfer of the main batch to V1001. The solids were successfully mobilised, but it was necessary to charge additional water as an anti-solvent to compensate for the extra THF. In spite of the additional water charge, it is likely that this deviation will have resulted in some loss of product to the liquors. To prevent a repetition of the losses observed in S5 and S6, the following measures are proposed or have already been implemented: Particular attention should be paid to isolation of the Stage 3 product on the centrifuge. Efficient de-liquoring at this point is essential to removing the unwanted regioisomer and thereby avoiding the need for additional methanol washes at Stage 3a. Larger agitator blades have been fitted to V3166. The resulting improved agitation should avoid the need to charge additional THF to the reaction mixture as in S5. The reaction mixture should be quenched with water in V3166 before transfer to V1001. This should avoid the problems associated with solids settling out in V3166 during the transfer. Once quenched, the mixture is much more mobile and should be transferred more readily, In addition to the above changes, an increased reaction concentration has now been demonstrated at Pilot scale. This will result in a significant improvement in volumetric efficiency and allow a larger batch size to be accommodated. Process Outline Below is the process outline of the Stage 3a process employed in Campaign S6. Process outlines for Campaigns S3, S4 and S5 are contained in the relevant campaign reports. Step Description 1. Charge N-methyl indole acid Stage 3 (362 Kg) to vessel V3166 via the solids charging chute. 2. Charge tetrahydrofuran (56 Kg) to vessel V3166 via solids charge chute as a rinse. 3. Charge tetrahydrofuran (770 Kg) to vessel V3166 via drums. 4. Start V3166 agitator. 5. Charge pyridine (138 Kg) to vessel V3166 via drums. 6. Charge tetrahydrofuran (92 Kg) to vessel V3166, via drums, as a line-wash. 7. Cool contents of vessel V3166 to 10-20° C. 8. Charge acetyl chloride (119 Kg) to dispenser R3173. 9. Transfer contents of dispenser R3173 to vessel V3166 at a rate that maintains the batch temperature in the range 10 to 25° C. 10. Charge tetrahydrofuran (92 Kg) to vessel V3166, via dispenser R3173, as a line wash. 11. Stir contents of vessel V3166 at 20 to 30° C. for NLT 4 hours. 12. Sample contents of vessel V3166 for completion (DI/SD469/306). Limit: NMT 3% Stage 3 by HPLC area %. If complete, continue processing at Step 21. If incomplete, continue processing at Step 13. 13. Stir contents of vessel V3166 at 20 to 30° C. for NLT 2 hours. 14. Sample contents of vessel V3166 for completion (DI/SD469/306). Limit: NMT 3% Stage 3 by HPLC area %. If complete, continue processing at Step 21. If incomplete, continue processing at Step 15. 15. Charge pyridine (quantity specified by chemist) to vessel V3166 via dispenser R3173 maintaining the batch temperature in the range 20 to 30° C. 16. Charge tetrahydrofuran (45 Kg) to vessel V3166 via dispenser R3173. 17. Charge acetyl chloride (quantity specified by chemist) to vessel V3166 via dispenser R3173 maintaining the batch temperature in the range 20 to 30° C. 18. Charge tetrahydrofuran (45 Kg) to vessel V3166 via dispenser R3173. 19. Stir contents of vessel V3166 at 20 to 30° C. for NLT 2 hours. 20. Sample contents of vessel V3166 for completion (DI/SD469/306). Limit: NMT 3% Stage 3 by HPLC area %. If complete, continue processing at Step 21. If incomplete, consult chemist. 21. Transfer contents of vessel V3166 to vessel V1001. 22. Charge tetrahydrofuran (92 Kg) to vessel V3166 via drums. 23. Transfer contents of vessel V3166 to vessel V1001 as a line rinse. 24. Cool contents of vessel V1001 to 10 to 15° C. 25. During the cool back, charge water (631 L) to vessel V1 via bulk supply. 26. Charge contents of V1 to vessel V1001 over NET 1 hour, maintaining the batch temperature in the range 10 to 25° C. 27. Charge water (1261 L) to vessel V3166 via bulk supply and stir for NLT 30 minutes. 28. Transfer contents of V3166 to vessel V1001 maintaining the batch temperature in the range 10 to 25° C. 29. Charge water (631 L) to vessel V3166 via bulk supply and stir for NLT 30 minutes. 30. Transfer contents of V3166 to vessel V1001 maintaining the batch temperature in the range 10 to 25° C. 31. Agitate contents of vessel V1001 at 20-25° C. for NLT 2 hours. 32. Transfer approximately one fifth of the contents of vessel V1001 to centrifuge D3353. Collect liquors in receiver R3350. 33. Charge water (91 L) to header A3160 via drums. 34. Transfer contents of header A3160 to centrifuge D3353 as a cake wash, collecting liquors in receiver R3350. 35. Charge water (91 L) to header A3160 via drums. 36. Charge methanol (91 L) to header A3160 via bulk supply. Circulate to mix. 37. Transfer contents of header A3160 to centrifuge D3353 as a cake wash, collecting liquors in receiver R3350. 38. Drum up contents of receiver R3350 for disposal. 39. Discharge solids from centrifuge D3353 to kegs. 40. Repeat steps 32 to 39 three more times. 41. Transfer remaining contents of vessel V1001 to centrifuge D3353. Collect liquors in receiver R3350. 42. Charge water (91 L) to vessel V1001 via drums. 43. Transfer contents of vessel V1001 to centrifuge D3353 as a cake wash and line rinse, collecting liquors in receiver R3350. 44. Charge water (91 L) to header A3160 via drums. 45. Charge methanol (91 L) to header A3160 via bulk supply. Circulate to mix. 46. Transfer contents of header A3160 to centrifuge D3353 as a cake wash, collecting liquors in receiver R3350. 47. Drum up contents of receiver R3350 for disposal. 48. Discharge solids from centrifuge D3353 to kegs. 49. Sample wet cake for purity. (DI/SD469/307). Limit: NLT 93 area % Stage 3a If the analysis passes, continue at Step 83. If the analysis fails, and this is the first batch of the campaign, continue at step 50. If the analysis fails, and this is the second batch of the campaign, continue at step 50, but omit steps 74-82. 50. Charge wet cake to vessel V3166 via the charge chute. 51. Charge methanol (204 L, 1 full drum) to vessel V3166 via solids charge chute as a line rinse. 52. Charge bulk methanol (1453 L) to vessel V3166. 53. Start agitator and stir contents of V3166 for at least 15 minutes. 54. Transfer contents of V3166 to V1001. 55. Start V1001 agitator. 56. Charge bulk methanol (854 L) to vessel V3166, and stir for at least 15 minutes. 57. Transfer contents of V3166 to V1001 as vessel rinse. 58. Heat contents of vessel V1001 to reflux (65-67° C.). 59. Stir contents of vessel V1001 at reflux for NLT 1 hour. 60. Cool contents of vessel V1001 to 0 to 5° C. over about 2 hours. 61. Stir contents of vessel V1001 at 0 to 5° C. for NLT 1 hour. 62. During coolback charge bulk methanol (700 L) to header A3160 63. Cool contents of header A3160 to 0 to 5° C. 64. Transfer approximately one fifth of the contents of vessel V1001 to centrifuge D3353. Collect liquors in receiver R3350. 65. Transfer methanol (approximately 130 L) from header A3160 to centrifuge D3353 as a cake wash, collecting the liquors in receiver R3350. 66. Spin dry and discharge solids from centrifuge D3353 to kegs. 67. Repeat steps 64 to 66 three more times 68. Transfer remaining contents of vessel V1001 to centrifuge D3353. Collect liquors in receiver R3350. 69. Charge methanol (130 L) to vessel V1001 via bulk supply. 70. Cool contents of vessel V1001 to 0 to 5° C. 71. Transfer the contents of vessel V1001 to centrifuge D3353 as a cake wash and line rinse, collecting the liquors in receiver R3350. 72. Spin dry and discharge solids from centrifuge D3353 to kegs. 73. Transfer remaining contents of header A3160 directly to receiver R3350 and drum up R3350 contents for disposal. 74. V3166 Boil-out Between Batches Charge tetrahydrofuran (573 L -3 full drums) to vessel V3166 via drums. 75. Start agitator and set contents of vessel V3166 to reflux. 76. Allow contents of vessel V3166 to reflux for NLT 1 hour. 77. Cool contents of vessel V3166 to 25 to 30° C. 78. Transfer contents of vessel V3166 to vessel V1001. 79. Bake vessel V3166 dry under vacuum 80. Transfer contents of V1001 to receiver R3350. 81. Cool contents of vessel V1001 to 15 to 25° C. 82. Drum up contents of receiver R3350 for disposal. 83. Charge wet-cake to dryer K3045, keeping baskets separate. 84. Dry wet-cake in dryer K3045 at 35 to 45° C. until an LOD of NMT 0.5% is achieved. 85. Discharge product from dryer K3045 to drums. Expected dry weight = 333 Kg (81%) Equipment Train For Campaigns S3 and S4, Stage 3a manufacture, aqueous work-up and crystallisation were performed in PV351, a 300-gallon glass-lined vessel. The product was isolated in PD351 and PD404, ceramic vat-filters associated with PV351 and dried in PK602, a double cabinet air tray-dryer. Campaigns S5 and S6 were carried out in the RPS Dudley One Semi-works facility. The reaction chemistry took place in V3166, a 1000-gallon hastelloy reactor. The aqueous quench/crystallisation was performed in V1001, a 1000-gallon glass-lined vessel, and the product was isolated on D3353, a hastelloy peeler centrifuge. Drying took place in K3045, a stainless steel vacuum tray dryer. Quality-Critical Parameters No laboratory work to identify quality-critical parameters has been performed for Stage 3a. The product manufactured in Campaigns S3 to S6 has consistently satisfied specification and no quality-critical parameters have been identified from the processing records. The quality of the Stage 3a manufactured is largely determined by the quality of the Stage 3 input. In Campaign S3 and one batch of S6, relatively high levels of diiodo-Stage 3 were present in the Stage 3 input. This impurity was partially removed during the Stage 3a process, but not completely. This is reflected in the low purities for the relevant batches shown in Table One. Clearly, good control over formation of the diiodo impurity at Stage 3 is essential to generating high purity Stage 3a. The other main impurity observed in Stage 3a is the Stage 3a regioisomer. This is the product of acetylation of the corresponding Stage 3 impurity. Efficient centrifugation of the Stage 3 product is the main requirement for controlling the level of this impurity. As indicated earlier, the Stage 3a process includes provision for a methanol re-slurry if the wet-cake purity is below 93 area %. In reality, centrifugation results in high purity product and the re-slurry was employed in neither S5 nor S6. Parameters Affecting Yield In Campaigns S5 and S6, it proved necessary to charge additional THF to the process in order to achieve satisfactory slurry mobility. Although additional water (anti-solvent) was charged pro-rata to compensate for this, it seems likely that the additional solvent resulted in some yield losses. As described above, improved agitation and direct quenching of the batch in V3166 should remove the need for extra THF in future campaigns. The Stage 3 input for S6 batch 80012941A,B,C contained a high level of the Stage 3 regioisomer. This was acetylated to give the Stage 3a regioisomer and extra methanol centrifuge washes were applied to remove it from the product. These undoubtedly resulted in some yield loss. By ensuring efficient regioisomer removal at Stage 3, it should be possible to prevent such losses in future campaigns. Conversion of Stage 3 to Stage 3a is monitored by HPLC analysis of the reaction mixture. Table Two gives a comparison of final in-process levels of Stage 3 and the Stage 3 content of the isolated Stage 3a product. The current in-process limit for unreacted Stage 3 is 3 area % and this has remained unchanged since the process was introduced to the Dudley site in 2001. TABLE TWO Comparison of In-process and Intermediate Stage 3 levels for Stage 3a Campaigns S3 to S6 Final In-process Stage 3 in Isolated Stage 3 Stage 3a Campaign Batch (HPLC Area %) (HPLC Area %) S3 80009407A, B 1.0 A - ND B - ND S4 80010873A, B ND A - ND B - ND S5 80012347A, B ND A - ND B - ND 80012348A, B, C ND A - ND B - ND C - 0.9 S6 80012940A, B, C 2.5 A - ND B - ND C - 0.9 80012941A, B, C 0.3 A - ND B - ND C - 0.2 The data in Table Two indicate that in-process levels of unreacted Stage 3 up to 2.5 area % are well tolerated by the process. The S6 batch 80012940 gave a final completion result of 2.5 area % Stage 3, but the batch still had less than 1.0 area % of Stage 3 in the isolated product. It would therefore seem that the unreacted starting material is efficiently removed during isolation. From an economic viewpoint, this represents significant lost yield. It is therefore recommended that the in-process limit be lowered to 1 area %. There should be no difficulty in achieving this level. In fact, the lower limit has already been employed successfully in the recent Pilot Trial. TABLE THREE Comparison of Stage 3a In-process and Intermediate HPLC Purities for Campaigns S3 to S6 In-Process Intermediate Methanol HPLC Purity HPLC Purity Re-slurry Campaign Batch (Area %) (Area %) Employed? S3 80009407A, B 89.4 94.4 Yes S4 80010873A, B 97.6 99.9Yesa S5 80012347A, B99.0b 99.1c No 80012348A, B, C97.5b 98.7c No S6 80012940A, B, C96.8b 96.6c No 80012941A, B, C99.3b 99.0c No aRe-slurry performed, even though batch met in-process limit, for consistency with previous batches bValues shown are simple averages for all centrifuge basket-loads cValues shown are simple averages for all part-batches (A, B etc.) corresponding to oven charges All batches from Campaign S4 onwards have readily achieved the in-process limit and have therefore not required re-slurry. However, a re-slurry was employed for the S4 batch for the sake of consistency with earlier batches. The Stage 3a product isolated on the centrifuge in S5 and S6 had generally high purity (>98 area %). Batch 80012940 had atypically low purity (96.6 area %) on account of a high level of the diiodo impurity carried over from Stage 3. The high purity of batch 80012941 was ensured by employing additional methanol centrifuge washes to remove the regioisomeric impurity, which was present at high levels due to inefficient centrifugation of the Stage 3 input. With efficient centrifugation and good control over formation of the diiodo impurity at Stage 3, it should be possible to generate Stage 3a product with greater than 98 area % purity. Up to and including Campaign S6, the Stage 3a purity specification was set very low at ‘NLT 85 area %’. It has since been tightened to ‘NLT 94 area %’. The methanol re-slurry is known to be effective in upgrading the Stage 3a purity by removing the regioisomeric impurity and, to a lesser extent, the diiodo impurity. It would therefore be prudent to retain the in-process analysis, raising the limit to ‘NLT 94 area %’. This would allow material which failed to meet the purity specification to be upgraded before drying. TABLE FOUR Comparison of Stage 3a In-process and Intermediate LOD Values for Campaigns S3 to S6 Final In-process Intermediate LOD Campaign Batch LOD (% w/w) (% w/w) S3 80009407A, B0.2a A - ND B - ND S4 80010873A, B0.1a A - 0.1 B - 0.1 S5 80012347A 0.05 ND 80012347B 0.13 0.02 80012348A 0.14 ND 80012348B 0.12 0.05 80012348C 0.06 0.36 S6 80012940A ND 0.05 80012940B ND 0.04 80012940C 0.1 0.04 80012941A ND 0.04 80012941B 0.1 0.05 80012941A 0.1 0.04 aIn-process sample was composite of parts A and B Table Four shows good agreement between in-process and intermediate LOD values for Stage 3a. Based on this data, the current in-process limit is judged adequate to ensure that the intermediate specification (NMT 0.5% w/w) is achieved. Stage 3a HPLC Profile Table Five shows the Stage 3a HPLC profiles for Campaigns S3 to S6. The overall purity has generally been greater than 94 area %. In fact, when good control over the regioisomer and diiodo impurities is achieved, purity values in excess of 98 area % have been consistently observed. The overall purity of the Stage 3a product is less important than the levels of the individual impurities. For example, it is known that the diiodo impurity up to a level of 5.8 area % is removed at Stage 4. In contrast, there is no data to support onward processing of such high levels of the Stage 3a regioisomer. Stage 3a Regioisomer This impurity is formed by acetylation of the 3-iodo regioisomer formed as a major side-product at Stage 3. The level of the impurity is therefore determined by the amount of the 3-iodo compound present in the Stage 3 input. This, in turn, is determined by the efficiency of liquor removal and washing on the centrifuge. Good centrifuge technique at Stage 3 is therefore essential to controlling this impurity. If the impurity is detected at high levels in the Stage 3 product, it can be removed by means of an isopropyl alcohol re-slurry. It can also be removed at Stage 3a, by re-slurrying the wet-cake in methanol. Diiodo Impurity This impurity is generated at Stage 3 as a result of over-iodination. As yet, there is no proven method for removing it, although the Stage 3a methanol re-slurry is partially effective. Levels up to 5.8 area % have been tolerated by the Stage 4 process (Campaign S3). It is thought that the impurity is converted to the bis(TMS acetylene) compound under the Stage 4 conditions and that this is removed during the crystallisation. The current specification is ‘Report value’. RRTs 0.83 and 1.09 These impurities have only been detected in two part-batches. Their identity is not known.’ TABLE FIVE Stage 3a HPLC Profiles for Campaigns S3 to S6 Component (Area %) Stage 3a RRT Regio- Diiodo Campaign Batch Stage 3 0.83 isomer RRT 1.09 Stage 3a Impurity S3 80009407A ND ND ND ND 94.2 5.8 80009407B ND ND ND ND 94.5 5.5 S4 80010873A ND ND ND ND 100.0 ND 80010873B ND 0.21 <0.1 ND 99.7 ND S5 80012347A ND ND ND ND 99.13 0.87 80012347B ND ND ND ND 99.12 0.88 80012348A ND ND ND ND 99.25 0.75 80012348B ND ND ND ND 99.24 0.76 80012348C 0.9 ND 0.12 ND 97.9 1.1 S6 80012940A ND ND <0.1 ND 97.6 2.4 80012940B ND ND <0.1 ND 97.0 2.9 80012940C 0.9 ND <0.1 0.58 95.3 3.2 80012941A ND ND 0.4 ND 99.6 ND 80012941B ND ND 0.5 ND 99.2 0.7 80012941C ND ND 0.8 ND 98.2 1.0

References: [1]Current Patent Assignee: SCIOS - US2004/142940, 2004, A1 Location in patent: Page/Page column 14.
[2]Current Patent Assignee: SCIOS - WO2008/79105, 2008, A1 Location in patent: Page/Page column 21; 24-36.
[3]Current Patent Assignee: SCIOS - US2007/66833, 2007, A1 Location in patent: Page/Page column 9; 10-15.

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Yield	Reaction Conditions	Operation in experiment
86%	With copper(l) iodide In dichloromethane at 20℃; for 16h; Cooling with ice; Inert atmosphere;	57.1 ep 1: Preparation of methyl-2-chloro-4-acetamido-5-(2-trimethylsilylethynyl)-benzoate. To a stirred solution of 2-Chloro-4-acetamido-5-iodobenzoic acid methyl ester (2.5 g, 2.8 mmol) in dichloromethane (15.0 mL) were cuprous iodide (0.135 g, 0.71 mmol) and dichloro(bistriphenylphosphine)palladium(II) (0.25 g, 0.31 mmol). The mixture was cooled in an ice bath and added ethynyltrimethylsilane (0.825 g, 8.4 mmol). The resulting mixture was stirred under nitrogen at room temperature for 16 h. The mixture was diluted with dichloromethane (15.0 mL), washed with 5% citric acid, followed by water and dried (MgSO4). After the removal of the solvent, mixture was purified by silica gel flash chromatography using 20% ethyl acetate in heptane to afford the title compound as a light brown powder (1.9 g, 86%), m/z=252(MH+ -SiMe3).
84%	With copper(l) iodide; triethylamine In ethyl acetate at 28 - 42℃; for 4h; Industry scale;	2; 5 Example 2 Preparation of 2-Chloro-4-acetamido-5-(2-trimethylsilylethvnyl)-benzoic Acid Methyl Ester[0061] 2-Chloro-4-acetamido-5-iodobenzoic acid methyl ester (ca. 370 kg), bis(triphenylphosphine)Pd(II) chloride (3.84 kg), and copper (I) iodide (1.06 kg) were combined in a reaction vessel, and ethyl acetate (2048 kg) was added. The mixture was held at 28-32 0C while trimethylsilyl acetylene (122 kg) was added; this was rinsed in with 100 kg ethyl acetate. Triethylamine (126 kg) was then added, with the temperature kept below 40 0C, and the mixture was stirred at 38-42 0C for 4 hours or until less than 1% starting material remained by HPLC.[0062] The mixture was then cooled to 15-25 0C, and water (1100 L) was added; after stirring for 30 minutes, the aqueous layer was removed and discarded, and the aqueous wash was repeated with another 1100 L portion of water.[0063] It appears that treatment of this solution with Cuno carbon may be useful to reduce the amount of palladium residue remaining in the product and to improve the purity and color at later stages in the reaction sequence. In addition, an aqueous EDTA wash can be used at this stage to remove most of the copper salts present. [0064] The organic layer was then vacuum distilled without heating above 35 0C until the volume reached about 720 L. Heptane (937 kg) was added, and the vacuum distillation was repeated until the volume reached about 1400 L, removing most of the ethyl acetate present and crystallizing out the product. A second addition of heptanes and vacuum distillation may be added at this stage to further reduce the amount of ethyl acetate present, which may improve the yield without adversely affecting purity. [0065] This mixture was then cooled to 0-5 0C, and processed in five batches for product isolation. Each batch was spun down in a centrifuge, and was then rinsed with 186 L heptane. The wet cakes were combined for a yield of 84-87% averaged over several repetitions at about this scale (260-330 kg). The product was an off-white to brown powder that was 97-99+% pure as judged by HPLC.; Example 5 P A T E N T Attorney Docket: SCI5249WOPCTStage 3a Stage 4C10H9ClNO3I C15H18ClNO3Si F.W. 353.54 RW. 323.85 SCI-0216434 SCI-0216435[00106] For Campaign S3, the reaction stir-out period was extended from 4 to 8 hours in order to ensure complete consumption of the 3,5-diiodo impurity, which was present at an atypically high level (5.7 area %) in the Stage 3a product. The change was successful, in that the isolated Stage 4 product contained no detectable diiodo impurity. The change was purely temporary, due to the abnormal nature of the Stage 3a input. Subsequent campaigns reverted to the 4-hour reaction period.[00107] For Campaign S4, the product isolation procedure was modified to eliminate problems observed in Campaigns S2 and S3. The first vacuum distillation was terminated at a higher residual volume to prevent 'caking' of the product on the vessel walls as seen in S2. Heptane was then charged and a second vacuum distillation was performed to remove residual ethyl acetate. By ensuring adequate removal of ethyl acetate, it was anticipated that the yield losses seen in S3 would be avoided. The change proved highly successful. An excellent physical yield (96.0 %) was achieved in S4 and very little product adhered to the vessel walls during the isolation procedure. Satisfactory product purity was maintained.[00108] Stage 4 manufacture for Campaign S5 was scaled up by a factor of 2.33 from 115 to 268 kg.[00109] Campaign S6 was increased further by a factor of 1.26 to 338 kg (Stage 3a input). The only other change was a modification to the control software to maintain adequate agitation of the product slurry during the latter stages of transfer to the centrifuge. P A T E N T Attorney Docket: SCI5249WOPCT[00110] For both S5 and S6, the product was isolated on a centrifuge in place of the vat filter employed for S3 and S4. This resulted in more efficient liquor removal, which was reflected in improved product assay.Comparison of Yield and Purity for Campaigns S3 to S6.[00111] Table One gives a comparison of yield and purity data for Campaigns S3 to S6 inclusiveTable One: Stage 4 Yield and Purity Data for Campaigns S3 to S6a. Average value of part-batches[00112] A dramatic increase in Stage 4 physical yield was observed between Campaigns S3 and S4. The main reason for this was the modified isolation procedure, in which an additional heptane charge and vacuum distillation were incorporated. This lowered the proportion of ethyl acetate present in the supernatant liquors and thus lowered the product solubility in the liquors thereby improving the yield.[00113] The S5 yield was disappointing compared with S4. Several possible reasons for the shortfall were identified: P A T E N T Attorney Docket: SCI5249WOPCT iuiu 14j Jtimuisitieα material was observed throughout the aqueous layers during the phase separations. However, examination of this material in the laboratory showed mat it contained only small amounts of product.[00115] Mass balance studies indicated that the main losses were to the mother liquors. It appears that insufficient ethyl acetate was removed during the second vacuum distillation, despite the improvements made prior to S4. It is possible that the high yield observed in S4 was due to'over-stripping' as all volumes were estimated visually. In S5, volumes were measured more accurately by means of radar devices.[00116] Some of the losses may have resulted from poor centrifugation technique. If the product slurry or washes are fed too rapidly on to the centrifuge, physical losses may occur.[00117] On transferring the first S5 batch to the centrifuge, a significant quantity of solids remained in the crystallization vessel. Additional heptane had to be charged in order to mobilize this material and this will have had some detrimental effect on yield.[00118] For Campaign S6, attempts were made to avoid the losses highlighted in (3) and (4) above. Particular attention was paid to operation of the centrifuge in order to avoid overflow of the basket. Agitation was maintained throughout transfer of the product slurry to the centrifuge in order to prevent solids settling out. These efforts were successful in improving the yield although not to the S4 level.[00119] In general, the assay-based yields have been slightly lower than the physical yields reflecting the fact that the Stage 4 product generally has a lower assay than the Stage 3a input.Some variation in HPLC purity (area %) is seen across the campaigns (97.1 to 99.5 area %) although all batches have processed onward to give satisfactory purities in the downstream stages.Process Outline[00120] Below is the process outline of the Stage 4 process employed in Campaign S6. Process outlines for Campaigns S3, S4 and S5 are contained in the relevant campaign reports. The actual S6 charges were somewhat lower than those shown in the outline. P A T E N T Attorney Docket: SCI5249WOPCT P A T E N T Attorney Docket: SCI5249WOPCTStep DescriptionSample contents of vessel V3166 for completion (DI/SD469/401).Limit: NMT 1% Stage 3 A.23.If complete, continue processing at Step 26.If incomplete, continue processing at Step 24.24. Stir contents of vessel V3166 at 38 to 42 0C for NLT 2 hours.Sample contents of vessel V3166 for completion (DI/SD469/401).Limit: NMT 1% Stage 3A.25.If complete, continue processing at Step 26.If incomplete, consult chemist.26. Cool contents of vessel V3166 to 15 to 25 0C.Transfer approximately half the contents of VlOOl to vessel V3166 keeping the27. batch temperature in the range 15 to 25 0C.28. Stir contents of vessel V3166 at 15 to 25 0C for NLT 30 minutes.29. Allow contents of vessel V3166 to settle at 15 to 25 0C for NLT 30 minutes.Separate lower, aqueous layer to receiver R1002, retaining any interfacial material30. with the batch layer31. Drum up contents of receiver Rl 002 for disposal.Transfer remaining contents of VlOOl to vessel V3166 keeping the batch32. temperature in the range 15 to 25 0C.33. Stir contents of vessel V3166 at 15 to 25 °C for NLT 30 minutes.34. Allow contents of vessel V3166 to settle at 15 to 25 0C for NLT 30 minutes.35. Separate lower, aqueous layer and any interfacial material to receiver R1002.36. Drum up contents of receiver Rl 002 for disposal.37. Transfer contents of vessel V3166 to vessel VlOOl.Vacuum-distil solvent from vessel VlOOl to receiver R3350 until a residual38. volume of approximately 723 L is reached.Maximum batch temperature = 35 0C.Release vacuum to nitrogen and charge heptane (937 Kg) to vessel VlOOl from39. drums.Vacuum-distil solvent from vessel VlOOl to receiver R3350 until a residual40. volume of approximately 1408 L is reached.Maximum batch temperature = 35 0C.41. Cool contents of vessel VlOOl to 0 to -5 0C.42. Drum up contents of receiver R3350 for disposal. P A T E N T Attorney Docket: SCI5249WOPCTExpected dry weight = 285 kg (84 %)Equipment Train[00121] For Campaigns S3 and S4, Stage 4 aqueous work-up and crystallisation were performed in PV351, a 300-gallon glass-lined vessel. The product was isolated in PD351, a ceramic vat- filter associated with PV351 and dried in PK601, a single cabinet air tray-dryer. [00122] Campaigns S5 and S6 were carried out in V3166, a 1000-gallon hastelloy reactor. Crystallisation was performed in VlOOl, a 1000-gallon glass-lined vessel and the product was P A T E N T Attorney Docket: SCI5249WOPCT isolated on D3353, a hastelloy peeler centrifuge. Drying took place in K3045, a stainless steel vacuum tray dryer.Quality-Critical Parameters[00123] No laboratory work to identify quality-critical parameters has been performed for Stage 4.The product manufactured in Campaigns S3 to S6 has consistently met specification and no quality-critical parameters have been identified from the processing records. [00124] The main quality issue for Stage 4 has been the residual level of heavy metals (palladium and copper) in the isolated product. A substantial amount of work has been directed towards reducing the levels of these metals in the Stage 4 product and thus in subsequent stages. This work is described in detail in a separate report. The 'low-palladium' Stage 4 to 7 process has now been successfully demonstrated in the Pilot Plant on approximately 10 % of the full manufacturing scaleParameters Affecting Yield[00125] Four main factors affecting yield have been identified based on processing observations: [00126] During the work-up in Campaigns S5 and S6, significant amounts of emulsified material were found throughout the aqueous layer. This material was sampled and found to contain very little product. However, for the sake of process robustness, it was decided to evaluate filtering the two-phase mixture prior to separating the layers. This was demonstrated in the recent Pilot Campaign and gave rise to very clean separations.[00127] The Stage 4 product is crystallised by performing a solvent-exchange from ethyl acetate to heptane. Residual ethyl acetate solubilises the product resulting in loss of yield to the mother liquors. Varying degrees of efficiency in removing ethyl acetate are thought to be responsible for some of the yield variations observed in recent campaigns. In order to ensure consistently low levels of ethyl acetate, the effect of an additional heptane charge and vacuum distillation have been investigated. These modifications have consistently given physical yields in excess of 90 % at 10-L scale and in the recent Pilot Campaign.[00128] In the first batch of Campaign S5, a significant quantity of Stage 4 product remained in the crystalliser after transfer of the batch to the centrifuge. This was because the process-control software stopped agitation when the slurry reached a low volume in order to prevent splashing. The software has since been modified to continue stirring throughout the transfer, thereby preventing solids from settling out. P A T E N T Attorney Docket: SCI5249WOPCT[00129] Centrifuge technique is an important factor in preventing yield loss at each stage of the process. While none of the losses at Stage 4 have been directly attributed to poor centrifugation, it is important to ensure that the slurry and washes are applied at the correct rate in order to prevent product from spilling over the sides of the basket.Stage 4 Reaction Completion[00130] Conversion of Stage 3a to Stage 4 is monitored by HPLC analysis of the reaction mixture. Table Two gives a comparison of final in-process levels of Stage 3a and the Stage 3a content of the isolated Stage 4 product. The current in-process limit for unreacted Stage 3a is 1.0 area % and this has remained unchanged since Campaign S2. For Campaigns S3 to S6 inclusive, there was no intermediate specification for residual Stage 3 a. After S 6, a specification of 'NMT 1.0 area %' was introduced, based on the historical data shown in Table Two. All batches from S3 to S6 satisfied the 1.0 % limit with ease. However, the data in Table Two indicate that the in- process analysis underestimates the level of residual Stage 3 a relative to the intermediate analysis. This effect was even more pronounced in the Pilot Campaign (batch 800141090). Here, the final in-process analysis showed no Stage 3 a detected while one part-batch of the isolated product contained 1.16 area % and thereby failed to meet the specification. No satisfactory explanation has yet been put forward for this discrepancy.[00131] For safety reasons, the Pilot batch was cooled to -5 to 0 0C and the agitator was stopped before sampling. This contrasts with the earlier batches, where sampling was performed at the reaction temperature (38 to 42 0C) with agitation. Unreacted Stage 3a may have precipitated on cooling and settled to the base of the vessel in the absence of agitation. If this were the case, sampling the batch solution would not have given a true reflection of the Stage 3a level. [00132] The initial analysis performed on the Pilot batch 800141090 showed Stage 3a levels up to around 6 area %. Moreover, the apparent levels of Stage 3 a in a particular Stage 4 sample increased with time while the sample was stored as an acetonitrile solution in a glass vial. No similar increase was observed when the samples were prepared in PTFE vials. After an extensive analytical investigation, it was concluded that Stage 4 in acetonitrile degrades in glass vials to give an impurity that co-elutes with the Stage 3 a product. (It is highly improbable, from a chemical viewpoint, that the Stage 4 product actually reverts to Stage 3a). However, this sample degradation does not account for the apparent high level of Stage 3 a recorded for batch 800141090 (1.16 area %) since this value was obtained using PTFE vials. P A T E N T Attorney Docket: SCI5249WOPCT[00133] The intermediate analysis of S6 batches 80013029 A,B and 80013031A,B,C show high levels (up to 1 %) of an impurity which is distinct from Stage 3a but runs close to it, separated by about 0.1 minutes. It is possible that more than one impurity runs in this region. However, this still does not explain why the S6 completion analysis does not show any significant peaks in this region.[00134] Further work is clearly necessary to establish the reason(s) for the discrepancy between the intermediate and in-process residual Stage 3a levels. At present, the in-process test does not appear to be a reliable predictor of the Stage 3 a level in the isolated product.Table Two: Comparison of In-process and Intermediate Stage 3a levels for Stage 4 Campaigns S3 to S6Table Three: Comparison of In-process and Intermediate Stage 4 LOD Values for Campaigns S4 to S6 P A T E N T Attorney Docket: SCI5249WOPCTStage 3 a[00135] Residual Stage 3a runs between RRT 0.69 and 0.73. The data in Table Four show some variation in RRT values for this impurity. For this reason, it would be worthwhile re-analysing the retained S3 to S6 samples using the same HPLC equipment on the same day. Levels of Stage 3a recorded to date range from 0.1 to 0.56 area %. However, the recent Pilot Campaign yielded Stage 4 containing up to 1.16 area % Stage 3a. This failed the current specification (NMT 1.0 % Stage 3a), but was usage-tested to give Stages 5 and 7 with excellent purity and satisfying all specifications. It would therefore appear that the current specification is too tight and that it should be revised upwards, possibly with the aid of spiking experiments. The data in Table Four indicate that more than one impurity is found in the region RRT 0.69 to 0.73. One of these impurities apparently increases when Stage 4 samples are stored in acetonitrile in glass vials. Further work is required to determine the nature of this impurity and to achieve better separation from residual Stage 3a. Stage 4 Regioisomer[00136] The Stage 4 regioisomer is derived from the product of iodination at the 3-position, formed during the Stage 3 reaction. An authentic sample of the impurity has been synthesised and used as a reference standard to quantify levels in recent batches. Stage 4 batches from Campaigns S5 and S6 were analysed and the regioisomer was not detected at levels higher than 0.1 area %. Although the Stage 3 reaction generates up to 25 % of the regioisomeric iodo compound, it is largely removed during the isolation from DMF/water and the subsequent isopropyl alcohol centrifuge washes. In one batch of Campaign S6, a high level of the regioisomer was found in the isolated Stage 3 product and this was attributed to inefficient washing on the centrifuge. The impurity was readily removed at Stage 3a by employing additional methanol centrifuge washes during the isolation. Clearly, efficient centrifugation and washing at Stage 3 are vital to achieving good control over this impurity. Levels of Stage 4 regioisomer in excess of 0.1 area % have not been carried forward to Stage 5. It is therefore not possible to set a meaningful specification for this impurity at the present time. P A T E N T Attorney Docket: SCI5249WOPCTTable Jour: Stage 4 JHFJLCJ JfrotUes tor Campaigns S3 to S6
72.6%	With triethylamine In ethyl acetate at 28 - 42℃; for 4h;	2; 5.4 EXAMPLE 2; Preparation of 2-Chloro-4-acetamido-5-(2-trimethylsilylethynyl)-benzoic Acid Methyl Ester; 2-Chloro-4-acetamido-5-iodobenzoic acid methyl ester (ca. 370 kg), bis(triphenylphosphine)Pd(II) chloride (3.84 kg), and copper (I) iodide (1.06 kg) were combined in a reaction vessel, and ethyl acetate (2048 kg) was added. The mixture was held at 28-32° C. while trimethylsilyl acetylene (122 kg) was added; this was rinsed in with 100 kg ethyl acetate. Triethylamine (126 kg) was then added, with the temperature kept below 40° C., and the mixture was stirred at 38-42° C. for 4 hours or until less than 1% starting material remained by HPLC. The mixture was then cooled to 15-25° C., and water (1100 L) was added; after stirring for 30 minutes, the aqueous layer was removed and discarded, and the aqueous wash was repeated with another 1100 L portion of water. It appears that treatment of this solution with Cuno carbon may be useful to reduce the amount of palladium residue remaining in the product and to improve the purity and color at later stages in the reaction sequence. In addition, an aqueous EDTA wash can be used at this stage to remove most of the copper salts present. The organic layer was then vacuum distilled without heating above 35° C. until the volume reached about 720 L. Heptane (937 kg) was added, and the vacuum distillation was repeated until the volume reached about 1400 L, removing most of the ethyl acetate present and crystallizing out the product. A second addition of heptanes and vacuum distillation may be added at this stage to further reduce the amount of ethyl acetate present, which may improve the yield without adversely affecting purity. This mixture was then cooled to 0-5° C., and processed in five batches for product isolation. Each batch was spun down in a centrifuge, and was then rinsed with 186 L heptane. The wet cakes were combined for a yield of 84-87% averaged over several repetitions at about this scale (260-330 kg). The product was an off-white to brown powder that was 97-99+% pure as judged by HPLC.; EXAMPLE 5 For Campaign S3, the reaction stir-out period was extended from 4 to 8 hours in order to ensure complete consumption of the 3,5-diiodo impurity, which was present at an atypically high level (5.7 area %) in the Stage 3a product. The change was successful, in that the isolated Stage 4 product contained no detectable diiodo impurity. The change was purely temporary, due to the abnormal nature of the Stage 3a input. Subsequent campaigns reverted to the 4-hour reaction period. For Campaign S4, the product isolation procedure was modified to eliminate problems observed in Campaigns S2 and S3. The first vacuum distillation was terminated at a higher residual volume to prevent ‘caking’ of the product on the vessel walls as seen in S2. Heptane was then charged and a second vacuum distillation was performed to remove residual ethyl acetate. By ensuring adequate removal of ethyl acetate, it was anticipated that the yield losses seen in S3 would be avoided. The change proved highly successful. An excellent physical yield (96.0%) was achieved in S4 and very little product adhered to the vessel walls during the isolation procedure. Satisfactory product purity was maintained. Stage 4 manufacture for Campaign S5 was scaled up by a factor of 2.33 from 115 to 268 kg. Campaign S6 was increased further by a factor of 1.26 to 338 kg (Stage 3a input). The only other change was a modification to the control software to maintain adequate agitation of the product slurry during the latter stages of transfer to the centrifuge. For both S5 and S6, the product was isolated on a centrifuge in place of the vat filter employed for S3 and S4. This resulted in more efficient liquor removal, which was reflected in improved product assay. Comparison of Yield and Purity for Campaigns S3 to S6. Table One gives a comparison of yield and purity data for Campaigns S3 to S6 inclusive TABLE ONE Stage 4 Yield and Purity Data for Campaigns S3 to S6 Camp'n Stage 4 Camp'n Assay- HPLC Stage 3a Physical based Purity Stage 4 Input Stage 4 Output Yield Yield (Area Campaign Batch Number (kg) (kg) (%) (%) %) S3 800094080 102.5 68.2 72.6 Data not 97.5 available S4 800109390 114.5 96.0 96.0 93.2 98.9 S5 80012463A 274.1 202.2 84.2 81.6 99.5 80012465A 261.2 210.5 99.5 S6 80013029A, B 343.6 266.2 87.0 85.298.5a 80013131A, B, C 333.8 273.4 97.1a aAverage value of part-batches A dramatic increase in Stage 4 physical yield was observed between Campaigns S3 and S4. The main reason for this was the modified isolation procedure, in which an additional heptane charge and vacuum distillation were incorporated. This lowered the proportion of ethyl acetate present in the supernatant liquors and thus lowered the product solubility in the liquors thereby improving the yield. The S5 yield was disappointing compared with S4. Several possible reasons for the shortfall were identified: Emulsified material was observed throughout the aqueous layers during the phase separations. However, examination of this material in the laboratory showed that it contained only small amounts of product. Mass balance studies indicated that the main losses were to the mother liquors. It appears that insufficient ethyl acetate was removed during the second vacuum distillation, despite the improvements made prior to S4. It is possible that the high yield observed in S4 was due to ‘over-stripping’ as all volumes were estimated visually. In S5, volumes were measured more accurately by means of radar devices. Some of the losses may have resulted from poor centrifugation technique. If the product slurry or washes are fed too rapidly on to the centrifuge, physical losses may occur. On transferring the first S5 batch to the centrifuge, a significant quantity of solids remained in the crystallization vessel. Additional heptane had to be charged in order to mobilize this material and this will have had some detrimental effect on yield. For Campaign S6, attempts were made to avoid the losses highlighted in (3) and (4) above. Particular attention was paid to operation of the centrifuge in order to avoid overflow of the basket. Agitation was maintained throughout transfer of the product slurry to the centrifuge in order to prevent solids settling out. These efforts were successful in improving the yield although not to the S4 level. In general, the assay-based yields have been slightly lower than the physical yields reflecting the fact that the Stage 4 product generally has a lower assay than the Stage 3a input. Some variation in HPLC purity (area %) is seen across the campaigns (97.1 to 99.5 area %) although all batches have processed onward to give satisfactory purities in the downstream stages. Process Outline Below is the process outline of the Stage 4 process employed in Campaign S6. Process outlines for Campaigns S3, S4 and S5 are contained in the relevant campaign reports. The actual S6 charges were somewhat lower than those shown in the outline. Step Description 1. Charge N-Methyl Indole Acid Stage 3A (370 Kg) to vessel V3166 via the solids charge chute. 2. Charge dichlorobis(triphenylphosphine)palladium(II) (3.84 Kg) to vessel V3166 via the seed pot. 3. Charge copper (I) iodide (1.06 Kg) to vessel V3166 via the seed pot. 4. Charge ethyl acetate (2048 Kg) to vessel V3166 via drums. 5. Start agitator. 6. Purge vessel V3166 three times with nitrogen. 7. Heat contents of vessel V3166 to 28 to 32° C. 8. Charge (trimethylsilyl)acetylene (122 Kg) to dispenser R3173. 9. Transfer contents of dispenser R3173 to V3166 keeping the batch temperature in the range 28 to 32° C. 10. Charge ethyl acetate (100 Kg) to dispenser R3173. 11. Transfer contents of dispenser R3173 to V3166 keeping the batch temperature in the range 28 to 32° C. 12. If necessary, adjust batch temperature to 28 to 32° C. 13. Charge triethylamine (126 Kg) to dispenser R3173. 14. Transfer contents of dispenser R3173 to V3166 keeping the batch temperature in the range 28 to 40° C. 15. Charge ethyl acetate (100 Kg) to dispenser R3173. 16. Transfer contents of dispenser R3173 to V3166 keeping the batch temperature in the range 28 to 40° C. 17. Heat contents of vessel V3166 to 38 to 42° C. 18. Stir contents of vessel V3166 at 38 to 42° C. for NLT 4 hours. 19. During stir-out charge water (2228 L) to vessel V1001 via bulk supply. 20. Start V1001 agitator. 21. Sparge contents of vessel V1001 through dip pipe with nitrogen for NLT 30 minutes. 22. Hold contents of V1001 until needed at Step 27/32 23. Sample contents of vessel V3166 for completion (DI/SD469/401). Limit: NMT 1% Stage 3A. If complete, continue processing at Step 26. If incomplete, continue processing at Step 24. 24. Stir contents of vessel V3166 at 38 to 42° C. for NLT 2 hours. 25. Sample contents of vessel V3166 for completion (DI/SD469/401). Limit: NMT 1% Stage 3A. If complete, continue processing at Step 26. If incomplete, consult chemist. 26. Cool contents of vessel V3166 to 15 to 25° C. 27. Transfer approximately half the contents of V1001 to vessel V3166 keeping the batch temperature in the range 15 to 25° C. 28. Stir contents of vessel V3166 at 15 to 25° C. for NLT 30 minutes. 29. Allow contents of vessel V3166 to settle at 15 to 25° C. for NLT 30 minutes. 30. Separate lower, aqueous layer to receiver R1002, retaining any interfacial material with the batch layer 31. Drum up contents of receiver R1002 for disposal. 32. Transfer remaining contents of V1001 to vessel V3166 keeping the batch temperature in the range 15 to 25° C. 33. Stir contents of vessel V3166 at 15 to 25° C. for NLT 30 minutes. 34. Allow contents of vessel V3166 to settle at 15 to 25° C. for NLT 30 minutes. 35. Separate lower, aqueous layer and any interfacial material to receiver R1002. 36. Drum up contents of receiver R1002 for disposal. 37. Transfer contents of vessel V3166 to vessel V1001. 38. Vacuum-distil solvent from vessel V1001 to receiver R3350 until a residual volume of approximately 723 L is reached. Maximum batch temperature = 35° C. 39. Release vacuum to nitrogen and charge heptane (937 Kg) to vessel V1001 from drums. 40. Vacuum-distil solvent from vessel V1001 to receiver R3350 until a residual volume of approximately 1408 L is reached. Maximum batch temperature = 35° C. 41. Cool contents of vessel V1001 to 0 to -5° C. 42. Drum up contents of receiver R3350 for disposal. 43. Stir contents of vessel V1001 at 0 to -5° C. for NLT 1 hour. 44. Charge heptane (547 Kg) to header A3160. 45. Cool contents of header A3160 to 0 to -5° C. 46. Transfer approximately one quarter of the contents of vessel V1001 to peeler centrifuge D3353 taking liquors to receiver R3350. 47. Transfer approximately 186 L of heptane from header A3160 to peeler centrifuge D3353 as a cake wash, taking liquors to receiver R3350. 48. Spin dry and discharge solid to kegs. 49. Repeat steps 46-48 two more times. 50. Transfer remaining contents of vessel V1001 to peeler centrifuge D3353 taking liquors to receiver R3350. 51. Charge heptane (127 Kg) to vessel V1001. 52. Cool contents of vessel V1001 to 0 to -5° C. 53. Transfer contents of vessel V1001 to Peeler centrifuge D3353 as a cake wash, taking liquors to receiver R3350. 54. Spin dry and discharge solid to kegs. 55. Drum up contents of receiver R3350 for disposal. 56. Charge wet-cake to dryer K3045. 57. Dry wet-cake in dryer K3045 at 25 to 35° C. until an LOD of NMT 1.0% is achieved. 58. Discharge product from dryer K3045 to drums. Expected dry weight = 285 kg (84%) Equipment Train For Campaigns S3 and S4, Stage 4 aqueous work-up and crystallisation were performed in PV351, a 300-gallon glass-lined vessel. The product was isolated in PD351, a ceramic vat-filter associated with PV351 and dried in PK601, a single cabinet air tray-dryer. Campaigns S5 and S6 were carried out in V3166, a 1000-gallon hastelloy reactor. Crystallisation was performed in V1001, a 1000-gallon glass-lined vessel and the product was isolated on D3353, a hastelloy peeler centrifuge. Drying took place in K3045, a stainless steel vacuum tray dryer. Quality-Critical Parameters No laboratory work to identify quality-critical parameters has been performed for Stage 4. The product manufactured in Campaigns S3 to S6 has consistently met specification and no quality-critical parameters have been identified from the processing records. The main quality issue for Stage 4 has been the residual level of heavy metals (palladium and copper) in the isolated product. A substantial amount of work has been directed towards reducing the levels of these metals in the Stage 4 product and thus in subsequent stages. This work is described in detail in a separate report. The ‘low-palladium’ Stage 4 to 7 process has now been successfully demonstrated in the Pilot Plant on approximately 10% of the full manufacturing scale Parameters Affecting Yield Four main factors affecting yield have been identified based on processing observations: During the work-up in Campaigns S5 and S6, significant amounts of emulsified material were found throughout the aqueous layer. This material was sampled and found to contain very little product. However, for the sake of process robustness, it was decided to evaluate filtering the two-phase mixture prior to separating the layers. This was demonstrated in the recent Pilot Campaign and gave rise to very clean separations. The Stage 4 product is crystallised by performing a solvent-exchange from ethyl acetate to heptane. Residual ethyl acetate solubilises the product resulting in loss of yield to the mother liquors. Varying degrees of efficiency in removing ethyl acetate are thought to be responsible for some of the yield variations observed in recent campaigns. In order to ensure consistently low levels of ethyl acetate, the effect of an additional heptane charge and vacuum distillation have been investigated. These modifications have consistently given physical yields in excess of 90% at 10-L scale and in the recent Pilot Campaign. In the first batch of Campaign S5, a significant quantity of Stage 4 product remained in the crystalliser after transfer of the batch to the centrifuge. This was because the process-control software stopped agitation when the slurry reached a low volume in order to prevent splashing. The software has since been modified to continue stirring throughout the transfer, thereby preventing solids from settling out. Centrifuge technique is an important factor in preventing yield loss at each stage of the process. While none of the losses at Stage 4 have been directly attributed to poor centrifugation, it is important to ensure that the slurry and washes are applied at the correct rate in order to prevent product from spilling over the sides of the basket. Stage 4 Reaction Completion Conversion of Stage 3a to Stage 4 is monitored by HPLC analysis of the reaction mixture. Table Two gives a comparison of final in-process levels of Stage 3a and the Stage 3a content of the isolated Stage 4 product. The current in-process limit for unreacted Stage 3a is 1.0 area % and this has remained unchanged since Campaign S2. For Campaigns S3 to S6 inclusive, there was no intermediate specification for residual Stage 3a. After S6, a specification of ‘NMT 1.0 area %’ was introduced, based on the historical data shown in Table Two. All batches from S3 to S6 satisfied the 1.0% limit with ease. However, the data in Table Two indicate that the in-process analysis underestimates the level of residual Stage 3a relative to the intermediate analysis. This effect was even more pronounced in the Pilot Campaign (batch 800141090). Here, the final in-process analysis showed no Stage 3a detected while one part-batch of the isolated product contained 1.16 area % and thereby failed to meet the specification. No satisfactory explanation has yet been put forward for this discrepancy. For safety reasons, the Pilot batch was cooled to -5 to 0° C. and the agitator was stopped before sampling. This contrasts with the earlier batches, where sampling was performed at the reaction temperature (38 to 42° C.) with agitation. Unreacted Stage 3a may have precipitated on cooling and settled to the base of the vessel in the absence of agitation. If this were the case, sampling the batch solution would not have given a true reflection of the Stage 3a level. The initial analysis performed on the Pilot batch 800141090 showed Stage 3a levels up to around 6 area %. Moreover, the apparent levels of Stage 3a in a particular Stage 4 sample increased with time while the sample was stored as an acetonitrile solution in a glass vial. No similar increase was observed when the samples were prepared in PTFE vials. After an extensive analytical investigation, it was concluded that Stage 4 in acetonitrile degrades in glass vials to give an impurity that co-elutes with the Stage 3a product. (It is highly improbable, from a chemical viewpoint, that the Stage 4 product actually reverts to Stage 3a). However, this sample degradation does not account for the apparent high level of Stage 3a recorded for batch 800141090 (1.16 area %) since this value was obtained using PTFE vials. The intermediate analysis of S6 batches 80013029A,B and 80013031A,B,C show high levels (up to 1%) of an impurity which is distinct from Stage 3a but runs close to it, separated by about 0.1 minutes. It is possible that more than one impurity runs in this region. However, this still does not explain why the S6 completion analysis does not show any significant peaks in this region. Further work is clearly necessary to establish the reason(s) for the discrepancy between the intermediate and in-process residual Stage 3a levels. At present, the in-process test does not appear to be a reliable predictor of the Stage 3a level in the isolated product. TABLE TWO Comparison of In-process and Intermediate Stage 3a levels for Stage 4 Campaigns S3 to S6 Final In-process Stage 3a in Isolated Stage 3a Stage 4 Campaign Batch (HPLC Area %) (HPLC Area %) S3 800094080 0.2 0.3 S4 800109390 0.06 0.09 S5 80012463A 0.1 0.39 80012465A 0.2 0.56 S6 80013029A, B ND 0.12 80013031A, B, C ND 0.39 TABLE THREE Comparison of In-process and Intermediate State 4 LOD Values for Campaigns S4 to S6 Final In- process Intermediate LOD (% LOD (% Campaign Batch w/w) w/w) S3 800094080 0.1 0.9 S4 800109390 0.3 0.1 S5 80012463A 0.04 0.02 80012465A ND ND S6 80013029A 0.2 0.07 80013029B 0.1 0.06 80013031A 0.1 0.06 80013031B 0.2 0.06 80013031C ND 0.06 Stage 3a Residual Stage 3a runs between RRT 0.69 and 0.73. The data in Table Four show some variation in RRT values for this impurity. For this reason, it would be worthwhile re-analysing the retained S3 to S6 samples using the same HPLC equipment on the same day. Levels of Stage 3a recorded to date range from 0.1 to 0.56 area %. However, the recent Pilot Campaign yielded Stage 4 containing up to 1.16 area % Stage 3a. This failed the current specification (NMT 1.0% Stage 3a), but was usage-tested to give Stages 5 and 7 with excellent purity and satisfying all specifications. It would therefore appear that the current specification is too tight and that it should be revised upwards, possibly with the aid of spiking experiments. The data in Table Four indicate that more than one impurity is found in the region RRT 0.69 to 0.73. One of these impurities apparently increases when Stage 4 samples are stored in acetonitrile in glass vials. Further work is required to determine the nature of this impurity and to achieve better separation from residual Stage 3a. Stage 4 Regioisomer The Stage 4 regioisomer is derived from the product of iodination at the 3-position, formed during the Stage 3 reaction. An authentic sample of the impurity has been synthesised and used as a reference standard to quantify levels in recent batches. Stage 4 batches from Campaigns S5 and S6 were analysed and the regioisomer was not detected at levels higher than 0.1 area %. Although the Stage 3 reaction generates up to 25% of the regioisomeric iodo compound, it is largely removed during the isolation from DMF/water and the subsequent isopropyl alcohol centrifuge washes. In one batch of Campaign S6, a high level of the regioisomer was found in the isolated Stage 3 product and this was attributed to inefficient washing on the centrifuge. The impurity was readily removed at Stage 3a by employing additional methanol centrifuge washes during the isolation. Clearly, efficient centrifugation and washing at Stage 3 are vital to achieving good control over this impurity. Levels of Stage 4 regioisomer in excess of 0.1 area % have not been carried forward to Stage 5. It is therefore not possible to set a meaningful specification for this impurity at the present time. TABLE FOUR Stage 4 HPLC Profiles for Campaigns S3 to S6 RRT Campaign Batch 0.13 0.69 0.70 0.71 0.73 0.85 1.00 1.17 S3 800094080 0.49 ND 0.34 0.32 ND ND 97.49 1.20 S4 800109390 ND ND ND 0.1 0.61 ND 98.69 ND S5 80012463A ND 0.39 ND ND ND ND 99.56 ND 80012465A ND 0.56 ND ND ND 0.39 99.05 ND S6 80013029A ND ND ND ND ND ND ND 98.5 ND 80013029B ND ND ND ND ND ND ND 98.5 ND 80013031A ND 0.7 0.5 ND ND ND ND 97.2 ND 80013031B ND 1.0 0.4 ND ND ND ND 96.7 ND 80013031C ND 0.5 0.3 ND ND ND ND 97.3 ND Current specification NLT 94

With triethylamine In dichloromethane at 0 - 20℃; for 12h;

3.C To a solution of compound 4-acetylamino-5-iodo-2-chloro-benzoic acid methyl ester (95 g, 269 mmol) in 51 mL Et3N and 290 mL CH2Cl2 was added CuI (0.50 g) and (Ph3P)2PdCl2 (1.05 g). It was then cooled to 0° C. and trimethylsilylacetylene (30.0 g) was added slowly. The temperature was raised to RT and stirring continued for 12 h. The mixture was poured into EtOAc and washed with water and brine. The organic layer was dried with Na2SO4 and concentrated. The residue was purified by column chromatography using EtOAc and hexane to give the product. M+H+(324).

References: [1]Current Patent Assignee: ACLARIS THERAPEUTICS - US2012/142696, 2012, A1 Location in patent: Page/Page column 29-30.
[2]Current Patent Assignee: SCIOS - WO2008/79105, 2008, A1 Location in patent: Page/Page column 22; 37-47.
[3]Current Patent Assignee: SCIOS - US2007/66833, 2007, A1 Location in patent: Page/Page column 9; 16-20.
[4]Current Patent Assignee: SCIOS - US2004/142940, 2004, A1 Location in patent: Page/Page column 14.

3
4-acetylamino-5-iodo-2-chloro-benzoic acid methyl ester [ No CAS ]
[ 162100-83-6 ]