145549-76-4|tert-Butyl 3-oxocyclobutanecarboxylate| Ambeed

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Quality Control of [ 145549-76-4 ] Purity: 95% SDS Specification

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Product Details of [ 145549-76-4 ]

CAS No. :	145549-76-4
Formula :	C₉H₁₄O₃
M.W :	170.21
SMILES Code :	CC(C)(C)OC(=O)C1CC(=O)C1
MDL No. :	MFCD12827541
InChI Key :	JINYZTGTQXDUQR-UHFFFAOYSA-N
Pubchem ID :	10261520

Safety of [ 145549-76-4 ]

GHS Pictogram:
Signal Word:	Warning
Hazard Statements:	H302-H315-H319
Precautionary Statements:	P261-P305+P351+P338

Computational Chemistry of [ 145549-76-4 ] Show Less

Physicochemical Properties

Num. heavy atoms	12
Num. arom. heavy atoms	0
Fraction Csp3	0.78
Num. rotatable bonds	3
Num. H-bond acceptors	3.0
Num. H-bond donors	0.0
Molar Refractivity	44.79
TPSA ? Topological Polar Surface Area: Calculated from Ertl P. et al. 2000 J. Med. Chem.	43.37 Å²

Lipophilicity

Log P_o/w (iLOGP)? iLOGP: in-house physics-based method implemented from Daina A et al. 2014 J. Chem. Inf. Model.	2.0
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	0.52
Log P_o/w (WLOGP)? WLOGP: Atomistic method implemented from Wildman SA and Crippen GM. 1999 J. Chem. Inf. Model.	1.31
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.	0.9
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	1.64
Consensus Log P_o/w? Consensus Log P_o/w: Average of all five predictions	1.27

Water Solubility

Log S (ESOL):? ESOL: Topological method implemented from Delaney JS. 2004 J. Chem. Inf. Model.	-1.02
Solubility	16.1 mg/ml ; 0.0944 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	Very soluble
Log S (Ali)? Ali: Topological method implemented from Ali J. et al. 2012 J. Chem. Inf. Model.	-1.0
Solubility	17.0 mg/ml ; 0.0996 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	Very 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	-1.54
Solubility	4.9 mg/ml ; 0.0288 mol/l
Class? Solubility class: Log S scale Insoluble < -10 < Poorly < -6 < Moderately < -4 < Soluble < -2 Very < 0 < Highly	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	No
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	No
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.	-6.97 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	1.0
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	0.0 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)	1.95

Application In Synthesis of [ 145549-76-4 ]

* 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 [ 145549-76-4 ]

[ 145549-76-4 ] Synthesis Path-Downstream 1~35

1
[ 35160-95-3 ]
[ 145549-76-4 ]
[ 145549-80-0 ]

References: [1]Journal of Organic Chemistry,1993,vol. 58,p. 100 - 110.

2
[ 1449-46-3 ]
[ 145549-76-4 ]
tert-butyl (+/-)-3-(phenylmethylene)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Journal of Organic Chemistry,1993,vol. 58,p. 100 - 110.

3
[ 23761-23-1 ]
[ 75-65-0 ]
[ 145549-76-4 ]

Yield	Reaction Conditions	Operation in experiment
89%	With dicyclohexyl-carbodiimide; In dichloromethane; at 20℃;	To a solution of commercially available 3-oxocyclobutanecarboxylic acid (11.4 g, 100 mmol) in anhydrous DCM (100 mL) was added DCC (31 g, 150 mmol) and 2 methylpropan-2-ol (8.9 g, 120 mmol), then the mixture was stirred at room temperature overnight. The mixture was quenched withaqueous H20, extracted with DCM, the organic layer was washed with brine, dried over anhydrous Na2SO4, filtered and concentrated in vacuo. The residue was purified by column to give reagent R-28b (15.1 g, 89percent yield).
	With dmap; dicyclohexyl-carbodiimide; In dichloromethane; at 20℃; for 20h;	Reference Example 4 Tert-butyl 3-oxocyclobutane carboxylate To dichloromethane solution (1.6 L) comprising 3-oxocyclobutane carboxylic acid obtained from Reference example 3, tert-butanol (429 g), 4-dimethylaminopyridine (283 g), dichloromethane solution (700 mL) comprising DCC (656 g) was added and the mixture was stirred at room temperature for twenty hours. Upon the completion of stirring, the reaction solution was filtered using Celite, and washed with 1N hydrochloric acid solution. The organic layer was washed with saturated sodium bicarbonate solution, and then dried over magnesium sulfate. Solids were removed, and the filtrate was dried under reduced pressure to obtain the title compound (530 g). 1H-NMR (CDCl3): 3.28 (4H, m), 1.48 (9H, s).
250 g	With dmap; dicyclohexyl-carbodiimide; In tetrahydrofuran; at 10 - 35℃; for 16.5h;	To a solution of 3-oxocyclobutanecarboxylic acid (250 g) in THF (1.5 L) were added tert-butanol (228 g) and 4-dimethylaminopyridine (148 g) at room temperature, and a solution of N,N'-dicyclohexylcarbodiimide (497 g) in THF (0.5 L) was added dropwise thereto over 30 min, and the reaction mixture was stirred at room temperature for 16 hr. The reaction mixture was filtered through Celite, and the filtrate was concentrated under reduced pressure. The residue was diluted with ethyl acetate, and the mixture was washed with 1M hydrochloric acid, saturated aqueous sodium hydrogencarbonate solution and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was diluted with petroleum ether, the mixture was filtered through Celite, and the filtrate was concentrated under reduced pressure to give the title compound (250 g). 1H NMR (500 MHz, CDCl3) delta 1.48 (9H, s), 3.12-3.14 (1H, m), 3.21-3.27 (2H, m), 3.33-3.35 (2H, m).

References: [1]Patent: WO2014/131855,2014,A1 .Location in patent: Page/Page column 77.
[2]Journal of Medicinal Chemistry,2016,vol. 59,p. 8967 - 9004.
[3]Journal of Organic Chemistry,1993,vol. 58,p. 100 - 110.
[4]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.
[5]Patent: US2009/298894,2009,A1 .Location in patent: Page/Page column 44.
[6]Patent: US2017/283406,2017,A1 .Location in patent: Paragraph 0685; 0686.

4
[ 145549-76-4 ]
(+/-)-3-(phenylmethylene)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Journal of Organic Chemistry,1993,vol. 58,p. 100 - 110.

5
[ 145549-76-4 ]
(+/-)-3-(2-naphthalenylmethylene)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Journal of Organic Chemistry,1993,vol. 58,p. 100 - 110.

6
[ 463-82-1 ]
[ 23761-23-1 ]
[ 145549-76-4 ]

Yield	Reaction Conditions	Operation in experiment
	With sulfuric acid; magnesium sulfate; In dichloromethane; at 20℃; for 60h;	A Concentrated sulfuric acid (5 ML, 90 mmol) was added to a vigorously stirred suspension of anhydrous MGS04 (42 g, 350 mmol) in DCM (250 mL). The mixture was stirred for 15 minutes before Intermediate 1 (10 g, 88 mmol) was added followed by tert-butanol (42.5 ML, 438 mmol). The reaction flask was stoppered tightly and stirred at room temperature for 60 hours. Saturated NaHC03 solution was added and the resulting mixture was stirred until the reaction mixture became clear as all MGS04 dissolved. The organic layer was separated and washed with brine, dried over anhydrous MGS04, and concentrated in vacuo. The crude product was used in next step.

References: [1]Patent: WO2004/82682,2004,A1 .Location in patent: Page 78.

7
[ 145549-76-4 ]
[ 149-73-5 ]
[ 766513-46-6 ]

Yield	Reaction Conditions	Operation in experiment
64.3%Chromat.	With toluene-4-sulfonic acid; In methanol; dichloromethane; at 20℃; for 1h;	B The product from Step A (15 g, 88 mmol) was dissolved in DCM (100 ML) and MeOH (100 mL) first before trimethyl orthoformate (96 ML, 880 mmol) was added. TSOH (1.7 g, 8.8 mmol) was added last. The reaction mixture was stirred at room temperature for 1 hour before being concentrated IN VACUO. The concentrate was diluted with ether, quenched with saturated NAHC03, washed with brine, dried over anhydrous MGS04, and concentrated to dryness. The crude product was purified by MPLC (10: 90, EtOAc: hexanes) to yield the desired product (12.21g, 64.3percent for last two steps). 1H NMR (400 MHz, CDC13) 8 3.17 (d, J=6.4 Hz, 6H), 2.80 (p, J=8.8 Hz, 1H), 2.43-2. 31 (m, 4H), 1.47 (s, 9H).

References: [1]Patent: WO2004/82682,2004,A1 .Location in patent: Page 78-79.

8
[ 145549-76-4 ]
[ 1311166-10-5 ]

Yield	Reaction Conditions	Operation in experiment
		Reference Example 5; Tert-butyl 3-azidecyclobutane carboxylate; Step 1:; To ethanol solution (2.9 L) comprising <strong>[145549-76-4]tert-butyl 3-oxocyclobutane carboxylate</strong> (490 g) obtained from Reference example 4, ethanol suspension (1.8 L) comprising sodium borohydride (54.4 g) was added while maintaining the temperature at 5° C. After stirring for one hour, the reaction solution was added with ammonium chloride solution to terminate the reaction. The mixture was extracted with dichloromethane and the organic layer was dried over magnesium sulfate. Solids were removed, and the filtrate was dried under reduced pressure.
	With sodium tetrahydroborate; In tetrahydrofuran; methanol; at 0 - 5℃; for 2h;	A mixture of tert-butyl 3- oxocyclobutanecarboxylate (15, 1.50 g, 8.8 mmol) in THF:MeOH (3 : 1 , 16 mL) was added dropwise to a stirring slurry of sodium borohydride (0.167 g, 4.4 mmol) in THF (8 mL) in round bottom flask cooled in an ice bath. The mixture was stirred at 0-5 °C for two hours. Water was added dropwise (10 mL) followed by aq. Na2C03, and the mixture was extracted with ethyl acetate. The combined organic layers were washed with brine and dried over sodium sulfate. After filtration, the organic layer was concentrated to give the crude tert-butyl 3- hydroxycyclobutanecarboxylate (16) as a white semi-solid (2.3 g, 100percent), which was used in the next step without purification. p-Toluenesulphonyl chloride (4.201 g, 0.022 moles) was added to a stirring solution of crude tert-butyl 3 -hydroxycyclobutanecarboxylate (16, 2.30 g, 8.8 mmol) in dry pyridine (10 mL) and CH2C12 (20 mL) at 0 °C. The mixture was allowed to warm to room temperature and stirred under nitrogen overnight. The solvent was then removed under reduced pressure and the residue was partitioned between ethyl ether (100 mL) and 0.5 N aq. HC1 (20 mL). The organic layer was separated and washed with saturated NaHC03 and brine, and dried (Na2S04). After filtration, the solvent was removed under reduced pressure and the residue purified by silica gel flash chromatography (0-50percent EtOAc-hexane) to afford tert-butyl 3- (tosyloxy)cyclobutanecarboxylate (17) as a colorless oil that slowly solidified at room temperature (2.6 g, 90percent yield over 2 steps). 1H NMR (300 MHz, CDC13): delta 7.79 (d, 2H, J = 8.4 Hz), 7.35 (d, 2H, J = 8.1 Hz), 4.72 (m, 1H), 2.60-2.30 (m, 8H), 1.44 (s, 9H).
	With sodium tetrahydroborate; In tetrahydrofuran; methanol; at 0 - 5℃; for 2h;	A mixture of tert-butyl 3- oxocyclobutanecarboxylate (1, 1.50 g, 8.8 mmol) in THF:MeOH (3 : 1 , 16 mL) was added dropwise to a stirring slurry of sodium borohydride (0.167 g, 4.4 mmol) in THF (8 mL) in round bottom flask cooled in an ice bath. The mixture was stirred at 0-5 °Cfor two hours. Water was added dropwise (10 mL) followed by aq. Na2CO3, and the mixture was extracted with ethyl acetate. The combined organic layers were washed with brine and dried over sodium sulfate.After filtration, the organic layer was concentrated to give the crude tert-butyl 3- hydroxycyclobutanecarboxylate (2) as a white semi-solid (2.3 g, 100percent),

References: [1]Patent: US2009/298894,2009,A1 .Location in patent: Page/Page column 44-45.
[2]Patent: WO2014/165307,2014,A2 .Location in patent: Paragraph 0306.
[3]Patent: WO2016/26978,2016,A1 .Location in patent: Page/Page column 37.

9
[ 1355090-65-1 ]
[ 145549-76-4 ]
[ 1355091-44-9 ]

Yield	Reaction Conditions	Operation in experiment
	With sodium tris(acetoxy)borohydride; at 20℃;	Compound 251. 3-{6-[(2,6-Dichlorophenyl)methoxy]-2H-spiro[l- benzofuran-3,4'-piperidine]-l'-yl}cyclobutane-l-carboxylic acid hydrochloride. To a mixture of 6-[(2,6-dichlorophenyl)methoxy]-2H-spiro[l- benzfuran-3,4'-piperidine] (0.5 g; 1.25 mmol) in dichloroethane (30 mL), was added tert-butyl 3-oxocyclobutane-l-carboxylate (276 mg; 1.62 mmol), sodiumtriacetoxyborohydride (423 mg; 2 mmol) and the resulting mixture was stirred at RT overnight. Subsequently, the mixture was diluted with EtOAc, washed with 5percent aqueous NaHC03, dried (Na2S04), and filtered. The residue was purified by column chromatography (S1O2, Et20:hexanes 1:1) to afford Tert butyl 3-{6-[(2,6-dichlorophenyl)methoxy]-2H-spiro[l-benzofuran-3,4'- piperidine]-l'-yl}cyclobutane-l-carboxylate (0.42 g; 65percent). Rt 1.50 min (System B), [M+H]+ 518.0, which was hydrolyzed using the 4M solution of HC1 in 1,4- dioxane conditions, affording the product (340 mg; 80percent). NMR (400 MHz, DMSO- de) delta ppm 12.5 (bs, 1H), 10.10 (bs, 1H), 7.55 -7.58 (m, 2H), 7.47 (dd, J =8.1 and 6.2 Hz, 1H), 6.98 - 7.02 (m, 1H), 6.56 - 6.62 (m, 2H), 5.18 (s, 2H),4.48 (bs, 2H), 3.57 - 3.62 (m, 1H), 3.26 - 3.44 (m, 2H), 2.78 - 2.93 (m, 3H), 2.35 - 2.53 (m, 2H), 1.78 - 2.18 (m, 4H). Rt 1.33 min (System B), [M+H]+ 461.9.

References: [1]Patent: WO2012/4378,2012,A1 .Location in patent: Page/Page column 208.

10
[ 145549-76-4 ]
[ 939768-64-6 ]

Yield	Reaction Conditions	Operation in experiment
98.83%	With methanol; sodium tetrahydroborate; In tetrahydrofuran; at 0 - 20℃; for 2.33333h;Inert atmosphere;	A 1L three-neck bottle was charged with nitrogen, 00 condition, to the suspension of Sodium borohydride (2.389 g, 63.158 mmol) in THF (108 mL, 0.886 g/mL, 1327.029 mmol) was added the solution of 3 -oxocyclobutanecarboxylate (21.5 g, 126.316 mmol) in MeOH (52 mL, 0.791 g/mL, 1283.684 mmol) and THF (160 mL, 0.886 g/mL, 1965.969 mmol) drop by drop in 20 minutes under nitrogen atmosphere. jCaution Gasemitting reactionJ jMonitor the inner reaction system tempearture no more than20.J The reaction mixture was stirred at 00 for 2 hours, TLC (3:1 = HEX: EA) to show the consumption of all starting material. The mixture was concentrated at reduced pressure to give a residue, which was added saturated Na2CO3 solution (200 mL) and extracted with EA (300mL X 3). The combined organic layers were washed with brine,dried over Na2 S04, filtered and the filtrate was concentrated to give a crude product (21.5 g, yield 98.83%) which was used without further purification for next step. ?H NIVIR (300 1VIHz, CDC13) 4.73 -4.69 (m, 1H), 4.16 -4.14 (m, 1H), 2.64 -2.40 (m, 3H), 2.27 - 2.06 (m, 2H), 1.44 (s, 9H).
70%	With sodium tetrahydroborate; ethanol; at 20 - 30℃; for 2h;	Preparation No.37: 3-Hydroxy-cyclobutanecarboxylic acid teri-butyl ester; A solution of teri-butyl 3-oxocyclobutanecarboxylate (prepared according to R.P. Lemieux, J. Org. Chem. (1993), Vol. 58, No. 1, pp. 100-110) (10.5g, 61.7 mmol) in EtOH (110 mL) was treated with sodium borohydride (2.173 mL, 61.7 mmol) portion wise at RT (cold water bath used to maintain reaction temperature below about 30 C) and the reaction was stirred at room temperature for about 2 h. The reaction was diluted with saturated NaCl solution (300 mL) and extracted with EtOAc (300 mL). The EtOAc layer was washed with saturated salt solution (3 x 200 mL), dried over sodium sulfate, filtered and concentrated. The crude product was further purified by distillation, taking the fraction that boils at about 88-90C at 3 Torr to yield 3-hydroxy-cyclobutanecarboxylic acid tert-butyl ester (7.37g, 70%) as colorless oil.LC/MS (Table 1, Method a), Rt = no peak, no parent ion; .H NMR (400 MHz, DMSO-d6) delta ppm 5.12 (d, J= 6.9, 1H), 3.97-3.88 (m, 1H), 2.46-2.29 (m, 3H), 1.94-1.86 (m, 2H), 1.39 (s, 9H).
	With sodium tetrahydroborate; In methanol; at -30℃; for 2.5h;Inert atmosphere;	A mixture of <strong>[145549-76-4]tert-butyl 3-oxocyclobutanecarboxylate</strong> (70.0 g, 411 mmol) in MeOH (700 mL) was added NaBH4 (15.6 g, 411 mmol) at -30 C under N2 over 2 h. The reaction mixture was stirred at -30 C for 0.5 h. The reaction mixture was quenched by the addition of with ice with sat. NH4C1 (700 mL) slowly at 0 C over 30 mm. The reaction mixture was concentrated under reduced pressure to leave the aqueous phase that was extracted with EtOAc (3 x 300 mL). The combined organics were washed with brine (300 mL), dried over anhydrous Na2SO4, filtered, and concentrated. Isolated as a mixture of diastereomers in favor of the c/s-product. ?H-NMR (400 MHz, CDC13): 4.23-4.04 (m, 1H), 2.79 (br s, 1H), 2.60 -2.43 (m, 3H), 2. 14-2.05 (m, 2H), 1.43 (s, 9H).

With methanol; sodium tetrahydroborate; at -30℃; for 2.5h;Inert atmosphere;

A mixture of tert-butyl 3- oxocyclobutanecarboxylate (70.0 g, 411 mmol) in MeOH (700 mL) was added NaBH4 (15.6 g, 411 mmol) at -30 °C under N2 over 2 h. The reaction mixture was stirred at -30 °C for 0.5 h. The reaction mixture was quenched by the addition of ice and aq. sat. NH4CI (700 mL) slowly at 0 °C over 30 min. The reaction mixture was concentrated under reduced pressure to leave the aqueous phase that was extracted with EtOAc (3 x 300 mL). The combined organics were washed with brine (300 mL), dried over anhydrous Na2S04, filtered, and concentrated. Mixture of diastereomers in favor of the cA-product. 'H-NMR (400 MHz, CDCI3): d 4.23-4.04 (m, 1H), 2.79 (br s, 1H), 2.60 -2.43 (m, 3H), 2.14-2.05 (m,2H), 1.43 (s, 9H).

References: [1]Patent: WO2019/1420,2019,A1 .Location in patent: Page/Page column 93; 121; 122.
[2]Patent: WO2011/71570,2011,A1 .Location in patent: Page/Page column 162.
[3]Patent: WO2019/32743,2019,A1 .Location in patent: Paragraph 0218; 0239.
[4]Patent: WO2019/183589,2019,A1 .Location in patent: Paragraph 0222.

11
[ 145549-76-4 ]
tert-butyl cis-3-(3-chloro-4-cyanophenoxy)cyclobutanecarboxylate [ No CAS ]

References: [1]Patent: WO2011/71570,2011,A1 .

12
[ 145549-76-4 ]
[ 939768-64-6 ]
[ 1311158-43-6 ]

References: [1]Organic Process Research and Development,2013,vol. 17,p. 666 - 671.

13
[ 145549-76-4 ]
3-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6H-pyrazolo[4,3-d]pyrimidin-5-yl)phenyl]cyclobutanecarboxylic acid [ No CAS ]

References: [1]Patent: WO2014/131855,2014,A1 .
[2]Journal of Medicinal Chemistry,2016,vol. 59,p. 8967 - 9004.

14
[ 145549-76-4 ]
3-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6H-pyrazolo[4,3-d]pyrimidin-5-yl)phenyl]cyclobutanecarbohydroxamic acid [ No CAS ]

References: [1]Patent: WO2014/131855,2014,A1 .
[2]Journal of Medicinal Chemistry,2016,vol. 59,p. 8967 - 9004.

15
[ 145549-76-4 ]
cis-3-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6H-pyrazolo[4,3-d]pyrimidin-5-yl)phenyl]cyclobutanecarbohydroxamic acid [ No CAS ]
trans-3-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6H-pyrazolo[4,3-d]pyrimidin-5-yl)phenyl]cyclobutanecarbohydroxamic acid [ No CAS ]

References: [1]Patent: WO2014/131855,2014,A1 .

16
[ 1491216-01-3 ]
[ 145549-76-4 ]
tert-butyl 3-[4-ethoxy-3-(1-methyl-7-oxo-3-propyl-6H-pyrazolo[4,3-d]pyrimidin-5-yl)phenyl]-3-hydroxy-cyclobutanecarboxylate [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
26%		n-BuLi (2.6 mL, 6.5 mmol) was added to a stirred suspension of intermediate I-94a (2.63 g, 6.0 mmol) in THE (60 mL) at 7O0C over a period of 5 mins under nitrogen. The resulting solution was stirred at 4O0C for 1 hr, and then then R-28b: <strong>[145549-76-4]tert-butyl 3-oxocyclobutanecarboxylate</strong> (1 .1 g, 6.5 mmol) in THE(10 mL) was added over a period of 5 mins under nitrogen. The resulting solution was stirred at room temperature for 15 hrs. The reaction was quenched aq.NH4CI and then extracted with EtOAc. The combined organic phase was washed with saturated brine, dried over anhydrous Na2SO4, filtered and concentrated in vacuo. The residue was purified by column togive the pure intermediate I-167a (830 mg, 26percent yield). ESI-MS (Mi-i): 483.2 calc. for C26H34N405: 482.2.

References: [1]Journal of Medicinal Chemistry,2016,vol. 59,p. 8967 - 9004.
[2]Patent: WO2014/131855,2014,A1 .Location in patent: Page/Page column 134; 135.

17
[ 145549-76-4 ]
tert-butyl 3-(tosyloxy)cyclobutanecarboxylate [ No CAS ]

References: [1]Patent: WO2014/165307,2014,A2 .
[2]Patent: WO2016/26978,2016,A1 .

18
[ 145549-76-4 ]
cis-tert-butyl 3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylate [ No CAS ]

References: [1]Patent: WO2014/165307,2014,A2 .

19
[ 145549-76-4 ]
trans-tert-butyl 3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylate [ No CAS ]

References: [1]Patent: WO2014/165307,2014,A2 .

20
[ 145549-76-4 ]
cis-3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Patent: WO2014/165307,2014,A2 .

21
[ 145549-76-4 ]
trans-3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Patent: WO2014/165307,2014,A2 .

22
[ 145549-76-4 ]
trans-tert-butyl 3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylate [ No CAS ]
cis-tert-butyl 3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylate [ No CAS ]

References: [1]Patent: WO2016/26978,2016,A1 .

23
[ 145549-76-4 ]
trans-3-(3,6-dichloro-9H-carbazol-9-yl)cyclobutanecarboxylic acid [ No CAS ]

References: [1]Patent: WO2016/26978,2016,A1 .

24
[ 145549-76-4 ]
3-(4-bromo-3-fluorophenyl)-3-hydroxy cyclobutane-1-carboxylic acid [ No CAS ]

References: [1]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.
[2]Patent: WO2019/55808,2019,A1 .

25
[ 145549-76-4 ]
3-(4-bromo-3-fluorophenyl)cyclobutane-1-carboxylic acid [ No CAS ]

References: [1]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.
[2]Patent: WO2019/55808,2019,A1 .

26
[ 145549-76-4 ]
6-bromo-7-fluoro-2,3-dihydro-1H-1,3-methanonaphthalen-4-one oxime [ No CAS ]

References: [1]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.

27
[ 145549-76-4 ]
6-bromo-7-fluoro-2,3-dihydro-1H-1,3-methanonaphthalen-4-one [ No CAS ]

References: [1]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.

28
[ 136434-77-0 ]
[ 145549-76-4 ]
tert-butyl 3-(4-bromo-3-fluorophenyl)-3-hydroxycyclobutane-1-carboxylate [ No CAS ]

Yield	Reaction Conditions	Operation in experiment
54%		To a 100 mL 3 -necked round-bottom flask was added a solution of l-bromo-2-fluoro-4- iodobenzene 40a (1 g, 3.32 mmol, 1.00 equiv.) in tetrahydrofuran (10.4 mL). A 2M solution of i-PrMgCl in THF (1.7 mL, 1.00 equiv) was added dropwise with stirring at 0°C during a 30 min period. The reaction mixture was stirred for another 3h at 0°C, then cooled to -70°C, and added with tert-Butyl 3-oxocyclobutane-l-carboxylate 40b (570 mg, 3.35 mmol, 1.00 equiv.) dropwise in 10 min. The resulting mixture was stirred at -78°C for lh, and continued at room temperature overnight. Water was added, the mixture was extracted with ethyl acetate (250 mL x 2), and the combined organic extracts were washed with a saturated H4CI aqueous solution (250 mL x 3), dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was purified by silica gel column chromatography eluting with ethyl acetate/petroleum ether (1 : 15) to afford tert-butyl 3 -(4-bromo-3-fluorophenyl)-3 -hydroxy cyclobutane-l-carboxylate 40c (620 mg, 54percent) as a light yellow oil.

References: [1]Patent: WO2019/55808,2019,A1 .Location in patent: Page/Page column 168.
[2]Journal of Medicinal Chemistry,2017,vol. 60,p. 627 - 640.

29
[ 145549-76-4 ]
C₁₄H₂₃NO₄ [ No CAS ]