Structure of 171178-50-0
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| CAS No. : | 171178-50-0 |
| Formula : | C6H3F2NO2 |
| M.W : | 159.09 |
| SMILES Code : | O=C(O)C1=C(F)N=C(F)C=C1 |
| MDL No. : | MFCD08064047 |
| InChI Key : | IEVMFAWRTJEFCF-UHFFFAOYSA-N |
| Pubchem ID : | 10583070 |
| GHS Pictogram: |
|
| Signal Word: | Warning |
| Hazard Statements: | H302-H315-H319-H332-H335 |
| Precautionary Statements: | P261-P280-P305+P351+P338 |
| Num. heavy atoms | 11 |
| Num. arom. heavy atoms | 6 |
| Fraction Csp3 | 0.0 |
| Num. rotatable bonds | 1 |
| Num. H-bond acceptors | 5.0 |
| Num. H-bond donors | 1.0 |
| Molar Refractivity | 31.11 |
| TPSA ? Topological Polar Surface Area: Calculated from |
50.19 Ų |
| Log Po/w (iLOGP)? iLOGP: in-house physics-based method implemented from |
0.94 |
| Log Po/w (XLOGP3)? XLOGP3: Atomistic and knowledge-based method calculated by |
1.25 |
| Log Po/w (WLOGP)? WLOGP: Atomistic method implemented from |
1.9 |
| Log Po/w (MLOGP)? MLOGP: Topological method implemented from |
-0.24 |
| Log Po/w (SILICOS-IT)? SILICOS-IT: Hybrid fragmental/topological method calculated by |
1.6 |
| Consensus Log Po/w? Consensus Log Po/w: Average of all five predictions |
1.09 |
| Log S (ESOL):? ESOL: Topological method implemented from |
-1.95 |
| Solubility | 1.78 mg/ml ; 0.0112 mol/l |
| Class? Solubility class: Log S scale |
Very soluble |
| Log S (Ali)? Ali: Topological method implemented from |
-1.9 |
| Solubility | 1.99 mg/ml ; 0.0125 mol/l |
| Class? Solubility class: Log S scale |
Very soluble |
| Log S (SILICOS-IT)? SILICOS-IT: Fragmental method calculated by |
-1.95 |
| Solubility | 1.81 mg/ml ; 0.0114 mol/l |
| Class? Solubility class: Log S scale |
Soluble |
| 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) |
No |
| CYP1A2 inhibitor? Cytochrome P450 1A2 inhibitor: SVM model built on 9145 molecules (training set) |
No |
| CYP2C19 inhibitor? Cytochrome P450 2C19 inhibitor: SVM model built on 9272 molecules (training set) |
No |
| CYP2C9 inhibitor? Cytochrome P450 2C9 inhibitor: SVM model built on 5940 molecules (training set) |
No |
| CYP2D6 inhibitor? Cytochrome P450 2D6 inhibitor: SVM model built on 3664 molecules (training set) |
No |
| CYP3A4 inhibitor? Cytochrome P450 3A4 inhibitor: SVM model built on 7518 molecules (training set) |
No |
| Log Kp (skin permeation)? Skin permeation: QSPR model implemented from |
-6.38 cm/s |
| Lipinski? Lipinski (Pfizer) filter: implemented from |
0.0 |
| Ghose? Ghose filter: implemented from |
None |
| Veber? Veber (GSK) filter: implemented from |
0.0 |
| Egan? Egan (Pharmacia) filter: implemented from |
0.0 |
| Muegge? Muegge (Bayer) filter: implemented from |
1.0 |
| Bioavailability Score? Abbott Bioavailability Score: Probability of F > 10% in rat |
0.56 |
| PAINS? Pan Assay Interference Structures: implemented from |
0.0 alert |
| Brenk? Structural Alert: implemented from |
1.0 alert: heavy_metal |
| Leadlikeness? Leadlikeness: implemented from |
No; 1 violation:MW<1.0 |
| Synthetic accessibility? Synthetic accessibility score: from 1 (very easy) to 10 (very difficult) |
1.73 |
* 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.

| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 62.9% | To a solution of 2,6-difluoropyridine (25.0 g, 217 mmol) in tetrahydrofuran (300 ml) was added dropwise 1.6 N n-butyllithium-hexane solution (163 ml) at -70 C., and the mixture was stirred at -70 C. for 1 hr. Dry ice (14.5 g, 330 mmol) was added at -70 C., and the mixture was stirred at -70 C. for 30 min, and then under ice-cooling for 1 hr. The reaction mixture was poured into ice water, and washed with ethyl acetate. The aqueous layer was adjusted to pH=3 with 3N hydrochloric acid, and extracted with ethyl acetate. The extract was washed with water, and dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was recrystallized from a mixed solvent of diethyl ether and hexane to give the object product (21.7 g, 62.9%) as a solid. 1H-NMR (CDCl3) δ; 6.89-6.94 (1H, m), 8.48-8.57 (1H, m). | |
| Synthesis of 2,6-difluoronicotinic acid A 2.62 M solution of n-butyllithium in THF (29.1 mL) was added dropwise to a solution of diisopropylamine (11.7 mL) in tetrahydrofuran (310 mL) under ice-cooling in a nitrogen atmosphere, and the reaction solution was stirred under ice-cooling for one hour. After cooling the reaction solution to -78C, a solution of 2,6-difluoropyridine [CAS# 1513-65-1] (8 g) in tetrahydrofuran (10 mL) was added dropwise to the reaction solution, and the reaction solution was stirred at -78C for three hours. Then, an excessive amount of crushed dry ice was added to the reaction solution in a nitrogen stream, and the reaction solution was stirred at -78C for 20 minutes and at room temperature for three hours. Water and diethyl ether were added to the reaction solution, and the aqueous layer was separated. The aqueous layer was adjusted to pH 1 with concentrated hydrochloric acid. Then, ethyl acetate was added and the organic layer was separated. The ethyl acetate layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to obtain 10.4 g of a crude product of the title compound. The property values of the compound are as follows. 1H-NMR (CD3OD) δ (ppm): 7.08 (dd, J = 8.4, 2.8 Hz, 1H) 8.58 (dd, J = 17.2, 8.4 Hz, 1H). | ||
| To a stirring -78 0C solution of LDA (91.34 ml of 1.8 M in heptane/THF/ethylbenzene, 164.41 mmol) and TBDF (201 ml) was added slowly over 20 min. a solution of 2,6- difluoropyridine (18.92 g, 164.41 mmol) in THF (20 ml) so that the internal temperature stayed below -70 0C. After the addition, the reaction was stirred for 3 h at -78 0C. Dry ice (about 22 g) was treated with a stream of N2 gas before being added to the mixture over a 5 min. period. The internal temperature rose to -50 0C as a result of an exothermic reaction. Once the internal temperature stabilized back to -78 0C, it was stirred for 30 min before being gradually warmed to RT arid then stirred for 18 h. The solution was acidified to pH 2.5 with HCl (10% aqueous solution). The organic solvents were removed under vacuum, and the aqueous layer was extracted twice with EtOAc. The combined organic layers were dried over Na2SO4, decanted, and concentrated under vacuum. The crude was treated with cold Et2O. The beige solid was isolated by filtration and washed twice with small amounts of cold diethyl ether to yield title compound. |
| 12.3 ml of N,N-diisopropylamine was mixed with 100 ml of THF. Thereafter, 50 ml of a hexane solution containing 1.6 mol/liter n-butyllithium was mixed therewith at -78C. The obtained mixture was stirred at -78C for 20 minutes. Thereafter, 10.1 g of 2,6-difluoropyridine dissolved in 50 ml of THF was added to the reaction mixture at -78C over 10 minutes. The obtained mixture was stirred for 30 minutes. Thereafter, dry ice was added to the reaction mixture, and the obtained mixture was stirred for 4 hours, while the temperature thereof was gradually raised to a room temperature. Thereafter, water was added to the reaction mixture, followed by partition with MTBE. Subsequently, concentrated hydrochloric acid was added to the water layer, so that the pH thereof was adjusted to pH 1, followed by extraction with ethyl acetate. The organic layer was washed with a saturated saline solution, and it was then dried over sodium sulfate, followed by concentration under reduced pressure. The obtained residue was washed with a mixed solvent of hexane and MTBE, so as to obtain 8.69 g of 2,6-difluoronicotinic acid.2,6-difluoronicotinic acid [Show Image] 1H-NMR (DMSO-D6) δ: 7.30 (1H, dd, J = 8.2, 2.4 Hz), 8.59 (1H, dd, J = 8.2, 4.1 Hz). | ||
| Example 8; Synthesis of Aldehyde ReagentsAldehyde reagents that are used in making compounds are prepared according to the following protocols. In these reactions, the unprotected aldehyde isolated after step 5, or the subsequently Boc-protected aldehyde may be used in preparation of compounds.(6-ethoxy-pyridin-3-yl)-(6-fluoro-5-formyl-pyridin-2-yl)-carbamic acid tert-butyl ester 57 is prepared in six steps from 2,6-difluoro-pyridine 39 as shown in Scheme 8. Step 1-Preparation of 2,6-difluoro-nicotinic acid (51)In a round bottom flask, to 2,6-difluoro-pyridine (39, 7.10 g, 61.7 mmol) in 150.0 mL of tetrahydrofuran under an atmosphere of nitrogen at -78 C., n-butyllithium (26.0 mL, 2.50 M in hexane, 65.0 mmol) is slowly added. After 30 minutes, 3.0 g of dry ice is added and an hour later the reaction is allowed to warm to room temperature. The reaction is poured into water, extracted with ethyl acetate and the aqueous layer is adjusted to pH 4-5 with 1 N hydrochloric acid. This is extracted with ethyl acetate and the organic layer is dried over sodium sulfate, filtered and the filtrate concentrated under vacuum to provide the desired compound (51, 5.6 g). |

| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 3.05 g | With thionyl chloride; In 1,2-dichloro-ethane; at 70℃; for 3h; | To a dichloroethane solution (28.0 mL) of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (3.41 g) was added thionyl chloride (9.16 mL) at room temperature, and the reaction mixture was stirred at 70C for 3 h After cooling to room temperature, the solvent was evaporated under reduced pressure. To a diethyl ether solution (46.0 mL) of the residue was added 28% aqueous ammonia (4.60 mL) at 0C and the mixture was stirred for 10 min. Saturated aqueous sodium hydrogen carbonate solution was added and the mixture was extracted with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated to give the title compound (3.05 g). MS(ESI)m/z; 159[M+H]+ |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| With thionyl chloride; In dichloromethane; for 3h;Heating / reflux; | 2,6-Difluoro-nicotinoyl chloride. A mixture of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (6.2 g), thionyl chloride (15 mL) and CH2Cl2 (100 mL) was heated to reflux for 3 h. The mixture was evaporated to dryness, CH2Cl2, was added and evaporated to dryness to afford 1.1 g of the <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> chloride. This material used without further purification. | |
| With thionyl chloride; In dichloromethane; for 1.5h;Heating / reflux; | EXAMPLE 1 Synthesis of 2-(2-fluoro,5-chloro)phenyl-7-fluoro-pyrido-8-pyrimidone. (Entry 7, Table II) 2,6 difluoronicotinic acid, (0.479 g, 3.012 mmol) was suspended in 30 mL dry methylene chloride and treated with thionyl chloride (2.5 mL, 34.27 mmol), under reflux for 90 minutes. The reaction mixture was cooled to room temperature and the solvents removed under reduced pressure on a rotary evaporator, the residue obtained was further dried under high vacuum to give 2,6 difluoronicotinoyl chloride. | |
| With thionyl chloride; for 2h;Inert atmosphere; Reflux; | 2,6-Difluoronicotinic acid (10.6 g, 66.6 mmol) and thionyl chloride (35 mF, 480 mmol) were combined under nitrogen and heated to gentle reflux for 2 h. The solution was concentrated to dryness under reduced pressure. Toluene (100 mF) was added to the crude and it was evaporated to dryness once more. The crude acid chloride was dissolved in DCM (50 mF) under nitrogen and cooled in an ice bath. A mixture of triethylamine (25 mF, 180 mmol) and benzyl alcohol (7.25 ml, 70.1 mmol) in DCM (50 mF) was added dropwise over 10 min. 0.1 N HC1 (100 mF) was added and the phases mixed and separated. The organic was dried with magnesium sulfate and evaporated to dryness under reduced pressure to provide benzyl 2,6-difluoronicotinate (50A) which was used without purification. m/z (ESI): 250.0 (M+H)+. |
| With thionyl chloride; for 2h;Inert atmosphere; Reflux; | 2,6-Difluoronicotinic acid (10.6 g, 66.6 mmol) and thionyl chloride (35 mL, 480 mmol) were combined under nitrogen and heated to gentle reflux for 2 h. The solution was concentrated to dryness under reduced pressure. Toluene (100 mL) was added to the crude and it was evaporated to dryness once more. The crude acid chloride was dissolved in DCM (50 mL) under nitrogen and cooled in an ice bath. A mixture of triethylamine (25 mL, 180 mmol) and benzyl alcohol (7.25 mL, 70.1 mmol) in DCM (50 mL) was added dropwise over 10 min, and the mixture was stirred at rt for 30 min. Then, 0.1 N HCl (100 mL) was added and the phases mixed and separated. The organic phase was taken, dried with magnesium sulfate, and evaporated to dryness under reduced pressure to provide benzyl 2,6-difluoronicotinate which was used without purification. m/z (ESI): 250.0 (M+H)+. |

| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| Step 2-Preparation of 2,6-difluoro-nicotinic acid methyl ester (52)In a round bottom flask, 2,6-difluoro-nicotinic acid (51, 5.60 g, 35.2 mmol), 60.0 mL of methanol and sulfuric acid (1.0 mL, 19.0 mmol) are combined and heated to reflux overnight. The reaction is poured into water, adjusted to pH around 9 with 1M aqueous potassium carbonate, and extracted with ethyl acetate. The organic layer is dried over sodium sulfate, filtered and the filtrate concentrated under vacuum to provide the desired compound as a yellow oil (52, 3.5 g). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 97% | With CO2; lithium diisopropyl amide; In tetrahydrofuran; cyclohexane; | EXAMPLE 64 4-(3-Bromoanilino)-7-fluoropyrido[2,3-d]pyrimidine 2,6-Difluoronicotinic acid. 2,6-Difluoropyridine (7.89 mL, 0.087 mmol) is added dropwise under N2 at 78 C. to a stirred solution of lithium diisopropylamide (59.0 mL of a 1.5N solution in cyclohexane, 0.089 mmol) in THF (250 mL). After 2 h at 78 C., a stream of dry CO2 is passed through the solution and the mixture is diluted with water and washed with EtOAc. The aqueous portion is neutralized with 3N HCl, extracted with EtOAc and worked up to give 2,6-difluoronicotinic acid (13.4 g, 97%). 1 H NMR (DMSO) δ 8.59 (1H, dd, J=9.2, 8.2 Hz), 7.30 (1H, dd, J=8.2, 2.1 Hz), 4.03 (1H, brs). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| With EDAC; benzotriazol-1-ol; N-ethyl-N,N-diisopropylamine; In dichloromethane; | EXAMPLE 154 Step A-Preparation of N-(4-tert-butyl-phenyl)-2,6-difluoro-nicotinamide A solution of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (3.2 g, 20 mmol), t-butylaniline (3.0 g, 20 mmol), HOBt (2.6 g, 20 mmol), EDAC (8 g, 40 mmol), and DIEA (8 mL) in CH2Cl2 (80 mL) was stirred at RT for 1 h. The mixture was washed with aq. NaHCO3 and brine. The organic solution was dried over Na2SO4 and concentrated in vacuo. The residue was purified via flash chromatography on silica (Hex:EtOAc=4:1) to give a light yellow flaky crystal as desired product. | |
| With EDAC; benzotriazol-1-ol; N-ethyl-N,N-diisopropylamine; In dichloromethane; | Step A-Preparation of N-(4-tert-butyl-phenyl)-2,6-difluoro-nicotinamide A solution of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (3.2 g, 20 mmol), t-butylaniline (3.0 g, 20 mmol), HOBt (2.6 g, 20 mmol), EDAC (8 g, 40 mmol), and DIEA (8 mL) in CH2Cl2 (80 mL) was stirred at RT for 1 h. The mixture was washed with aq. NaHCO3 and brine. The organic solution was dried over Na2SO4 and concentrated in vacuo The residue was purified via flash chromatography on silica (Hex:EtOAc=4:1) to give a light yellow flaky crystal as desired product. | |
| With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine; In dichloromethane; at 20℃; for 1h; | Step A-Preparation of N-(4-tert-butyl-phenyl)-2,6-difluoro-nicotinamide A solution of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (3.2 g, 20 mmol), t-butylaniline (3.0 g, 20 mmol), HOBt (2.6 g, 20 mmol), EDAC (8 g, 40 mmol), and DIEA (8 mL) in CH2Cl2 (80 mL) was stirred at RT for 1 h.The mixture was washed with aq. NaHCO3 and brine.The organic solution was dried over Na2SO4 and concentrated in vacuo. The residue was purified via flash chromatography on silica (Hex:EtOAc=4:1) to give a light yellow flaky crystal as desired product. |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 2,6-Difluoro-nicotinic acid. To a solution of anhydrous THF (50 mL) and diisopropyl amine (14.02 mL) cooled to-78C was added n-BuLi (2M, 50 mL). The mixture was allowed to warm to O0C for 30 min and was cooled to -780C. 2,6-Di- fluoropyridine (11.5 g) dissolved in THF (200 mL) was added to the LDA mixture at -780C. The mixture stirred at -780C for 2h, the ice bath was removed and the mixture stirred at O0C for 10 min. The mixture was cooled to -780C and a stream of CO2(g) was passed through the mixture for 15 minutes until the mixture became clear. The mixture stirred for 1 h at -780C and H2O (100 mL) was added. The ice bath was removed and the mixture warmed to rt. The THF was removed under reduced pressure and H2O (200 mL) was added followed by acidification to pH 3.5 with HCl. The mixture was extracted with EtOAc (3 x 150 mL). The combined organics were dried over MgSO4, filtered and evaporated to afford the 2,6-difluoronicotinic acid (9.4 g). Material used without further purification. | ||
| Synthesis of 2,6-difluoronicotinic acid; A solution of n-butyl lithium in THF (2.62 M, 29.1 mL) was added dropwise to a solution of diisopropylamine (11.7 mL) in tetrahydrofuran (310 mL) under ice-cooling in a nitrogen atmosphere. The reaction solution was stirred under ice-cooling for one hour and then cooled to -78 C. A solution of 2,6-difluoropyridine (8 g) in tetrahydrofuran (10 mL) was added dropwise to the reaction solution. The reaction solution was stirred at -0.78 C. for three hours. Then, an excess amount of crushed dry ice was added in a nitrogen stream, and the reaction solution was stirred at -78 C. for 20 minutes and at room temperature for three hours. Water and diethyl ether were added to the reaction solution, and the aqueous layer was separated. The aqueous layer was adjusted to pH 1 by concentrated hydrochloric acid. Ethyl acetate was added to the aqueous layer, and the organic layer was separated. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure to obtain 10.4 g of the title compound. 1H-NMR (CD3OD) δ (ppm): 7.08(dd,J=8.4,2.8 Hz,1H), 8.58(dd,J=17.2,8.4 Hz,1H). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| In tetrahydrofuran; (2S)-N-methyl-1-phenylpropan-2-amine hydrate; | (1) Fifty (50) g of 2,6-difluoropyridine was dissolved in 200 ml of tetrahydrofuran, and into the solution 326 ml of 1.6M n-butyl lithium-tetrahydrofuran solution was added dropwise at -70 C., followed by an hour's stirring at the same temperature. To the reaction mixture 29 g of dry ice blocks were added little by little, followed by 30 minutes' stirring at the same temperature. Raising the temperature to about 5 C., 500 ml of ice water was added. The reaction mixture was washed twice with ethyl acetate, and the aqueous layer was adjusted to pH 3 with conc. hydrochloric acid. The aqueous layer was then extracted with chloroform. The extract was washed with saturated saline water, dried over anhydrous magnesium sulfate, and the solvent was concentrated under reduced pressure. The crystalline precipitate was collected by filtration, and recrystallized from diethyl ether-n-hexane to provide 63 g of 2,6-difluoro-3-pyridinecarboxylic acid (m.p. 170-171 C.). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 76% | With thionyl chloride; ammonia; In diethyl ether; 1,2-dichloro-ethane; N,N-dimethyl-formamide; | 2,6-Difluoronicotinamide. A solution <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (7.4 g, 0.046 mmol) and SOCl2 (20 mL) in 1,2-dichloroethane (60 mL) containing DMF (1 drop) is heated under reflux for 4 h, then concentrated to dryness under reduced pressure. The residue is dissolved in Et2 O (100 mL), cooled to 0 C., and treated dropwise with concentrated ammonia (10.0 mL, 0.17 mmol). After 10 min the solution is washed with aqueous NaHCO3 and worked up to give 2,6-difluoronicotinamide (5.61 g, 76%). 1 H NMR (CDCl3) δ 8.70 (1H, dd, J=9.6, 8.3 Hz), 7.00 (1H, ddd, J=8.3, 2.9, 1.1 Hz), 6.71, 6.55 (1H, 1H, 2 brs). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 42% | With O-(benzotriazol-1-yl)-N,N,N',N'-tetramethyluronium tetrafluoroborate; triethylamine; In N,N-dimethyl-formamide; at 20℃; | To a solution of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (4.16 g, 26.2 mmol) and l-(4- fluorobenzyl)-2S,5R-dimethyl piperazine (4.8 g, 21.8 mmol) in dimethylformamide was added TBTU (10.5 g, 32.7 mmol) followed by triethylamine (9 mL, 65.4 mmol). The reaction mixture was stirred overnight at RT and then poured into ice water. The precipitate formed was filtered and dissolved in dichloromethane. Two scoops of silica gel were added to the solution. The mixture was concentrate under reduced pressure. The residue was dry loaded on silica gel column eluting with EtOAc:hexane(4:6) to give 4 g (42%) of the desired product as a white solid. M+H+(364). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 73% | With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine; In N,N-dimethyl-formamide; at 20℃; for 16h;Inert atmosphere; | A mixture of <strong>[171178-50-0]2,6-difluoropyridine-3-carboxylic acid</strong> (3.0 g, 18.9 mmol), N-methoxymethanamine hydrochloride (12.9 g, 132.0 mmol) hydroxybenzotriazole (10.2 g, 75.4 mmol), diisopropylethylamine (3.70 g, 28.7 mmol, 5.01 mL) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (7.20 g, 37.5 mmol) in N,N-dimethylformamide (50 mL) was stirred at 20 C for 16 h under a nitrogen atmosphere. The reaction mixture was diluted with water (30 mL) and extracted with dichloromethane (20 mL x 3). The combined organic phases were washed with saturated aqueous sodium chloride solution (20 mL x 3), dried overanhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 2,6-difluoro-N- methoxy-N-methyl-pyridine-3-carboxamide (2.80 g, 13.9 mmol, 73%) as a solid. |
| With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine; In N,N-dimethyl-formamide; at 20℃; for 48h; | Synthesis of 2,6-difluoro-N-methoxy-N-methylnicotinamide N,O-dimethylhydroxylamine hydrochloride (14.7 g), WSC (28.9 g), and HOBt (20.4 g) were added to a solution of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (6 g) and diisopropylethylamine (10 mL) in DMF (100 mL), and the reaction solution was stirred at room temperature for two days. Water and ethyl acetate were added to the reaction solution, and the organic layer was separated. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The resulting residue was purified by silica gel column chromatography (carrier: Chromatorex NH; elution solvent: ethyl acetate) to obtain 7.01 g of the title compound. 1H-NMR (CDCl3) δ (ppm): 3.37(s,3H), 3.58(brs,3H), 6.90(dd,J=8.0,2.8 Hz,1H), 8.02(dd,J=16.0,8.0 Hz,1H). | |
| With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; N-ethyl-N,N-diisopropylamine; In N,N-dimethyl-formamide; at 20℃; for 48h; | Synthesis of 2,6-difluoro-N-methoxy-N-methylnicotinamide N,O-dimethylhydroxylamine hydrochloride (14.7 g), HOBT (20.4 g) and EDC (28.9 g) were sequentially added to a solution of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (6 g) and IPEA (10 mL) in DMF (100 mL), and the reaction solution was stirred at room temperature for two days. Water and ethyl acetate were added to the reaction solution, and the organic layer was separated. The organic layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography using NH silica gel (elution solvent: ethyl acetate) to obtain 7.01 g of the title compound. The property values of the compound are as follows. 1H-NMR (CDCl3) δ (ppm): 3.37 (s, 3H), 3.58 (brs, 3H), 6.90 (dd, J = 8.0, 2.8 Hz, 1H) 8.02 (dd, J = 16.0, 8.0 Hz, 1H). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| In a 100 ml RBF were combined <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (1.47 g, 9.24 mmol), (IH- pyrrolo[2,3-]pyridin-4-yl)methanamine (1.36 g, 9.24 mmol), DIEA (2.39 g, 18.48 mmol), and TηF (35 ml). The mix was heated at 80 0C for 9 h. A beige solid was removed by filtration. The filtrate was concentrated under vacuum and then treated with CH2Cl2 to yield more beige solid, which was also isolated by filtration. The two batches of beige solid were combined and dissolved into 1 NNaOH (aq). The aqueous solution was extracted once with CH2Cl2 and then with EtOAc before being acidified to pH 4.5. The ensuing yellow precipitate was isolated by filtration and dried under vacuum to yield the titled compound. |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 83% | To a solution of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (1.0 g, 6.3 mmol) in THF (20 mL) at -78 0C was addedLiHMDS, 0.9M in methylcyclohexane (7.7 mL, 6.9 mmol) and the reaction was stirred at -78 0C for 1 hour. In a separate flask, a solution of (2R,6S)-2,6-dimethylmorpholine (0.78 mL, 6.3 mmol) in THF (20 mL) was cooled to -78 0C. LiHMDS, 0.9M in methylcyclohexane (7.7 mL,6.9 mmol) was added and the reaction was stirred for 1 hour. The contents of the second flask were added slowly to the first flask, maintaining the temperature at -78 C. LC/MS after stirring overnight indicates reaction is complete. The reaction mixture was diluted with IN HCl and extracted three times with ethyl acetate. The combined organic extracts were dried over magnesium sulfate, filtered and evaporated to a yellow solid (1.3g, 83% yield).MS (ES) MH+: 255 for Ci2Hi5FN2O31H NMR: 1.1 (d, 6H), 2.6 (dd, 2H), 3.6 (m, 4H), 6.4 (d, IH), 8.1 (t, IH). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| 50.3% | A mixture of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (1.00 g, 6.28 mmol) and thionyl chloride (10 ml) was stirred at 85 C. for 2 hr, and the solvent was evaporated under reduced pressure. The residue was added to a solution of tert-butyl 3-(hydroxymethyl)piperazine-1-carboxylate (1.00 g, 4.62 mmol) and triethylamine (1.29 ml, 9.24 mmol) in tetrahydrofuran (10 ml) under ice-cooling, and the mixture was stirred at room temperature for 1 hr. The reaction mixture was poured into water, and the mixture was extracted with ethyl acetate. The extract was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=1:1) to give the object product (830 mg, 50.3%) as a solid. 1H-NMR (CDCl3) δ; 1.47 (9H, s), 3.01 (3H, br s), 3.31-3.38 (1H, m), 3.61 (1H, br s), 3.78 (1H, br s), 4.12 (2H, br s), 4.45-4.48 (1H, m), 4.82 (1H, br s), 6.90-6.96 (1H, m), 7.94-8.06 (1H, m). |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| ~ 70% | The acid was suspended in 40 mL DCM and brought to reflux. During reflux a clear solution was obtained. After 3 hours the reaction mixture was cooled to room temperature and the reaction mixture concentrated on a rotary evaporator. The residue was dried on a vacuum pump for 30 minutes. To this dry residue was added 30 mL acetonitrile, the amidine and DIPEA. The mixture was brought to reflux under nitrogen and maintained at reflux for 70 minutes. Analysis of the reaction mixture at this time (LCMS), showed one major peak, mass 294. The reaction mixture was cooled to room temperature and concentrated on a rotary evaporator to give a dry residue. 30 mL of methanol was added to this residue and a precipitate formed. The solid was filtered and washed with ether and dried under vacuum to give a solid, 0.8 g. This material was dissolved in DMF to obtain a clear solution and analyzed by LCMS. One major peak, mass 294. The filtrate was concentrated to a solid and then suspended in 50 mL water. A precipitate forms. This suspension was acidified to pH 1-2, with 10% HCl. The solid that separates was filtered and washed with ether and dried under high vacuum. The analysis of this product shows it to be identical to the solid obtained from the first crop. (2) 0.58 g of solid was obtained in this fashion. Both batches of solid were combined and used for further reactions. 1.38 g total yield. Approximate yield 70%. |
| Yield | Reaction Conditions | Operation in experiment |
|---|---|---|
| To a mixture of <strong>[171178-50-0]2,6-difluoronicotinic acid</strong> (20.0 g), DMF (4 mL) and toluene (400 mL) was added oxalyl dichloride (11.9 mL) at 0C. The mixture was stirred at room temperature for 1 hr, and the solvent was evaporated under reduced pressure. THF (120 mL) was added to the residue, and a solution of N-benzylethanolamine (20.9 g) in THF was added. 8M Aqueous sodium hydroxide solution (40 mL) was added at 0C, and the resulting mixture was stirred at room temperature for 16 hr. Ethyl acetate and water were added, and the organic layer was washed with water and saturated brine and dried, and the solvent was evaporated under reduced pressure. THF (100 mL) was added to the obtained residue (34.5 g), and a suspension of sodium hydride (5.70 g) in THF (400 mL) was added dropwise at 0C. The mixture was stirred at room temperature for 16 hr, and water was added. The resulting product was extracted with ethyl acetate, the organic layer was washed with water and saturated brine and dried, and the solvent was evaporated under reduced pressure. The residue was purified by silica gel column chromatography (solvent gradient; 50→100% ethyl acetate/hexane) to give 4-benzyl-8-fluoro-3,4-dihydropyrido[3,2-f][1,4]oxazepin-5(2H)-one (11.2 g, 33%) as a yellow oil. 1H-NMR(CDCl3):δ3.61-3.64(2H,m), 4.38-4.41(2H,m), 4.82(2H,s), 6.74(1H,dd,J=3.4,8.3Hz), 7.20-7.40(5H,m), 8.67(1H,t,J=8.3Hz) |

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