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With hydrogenchloride In 1,4-dioxane at 20℃; for 3 h;
Step i: 2-amino-6,7-diriydrothiazolor5,4-clpyridin-4(5H)-one To a 50 mL round bottom flask, were added tert-butyl 2-amino-4-oxo-6,7-dihydrothiazolo[5,4- c]pyridine-5(4H)-carboxylate [intermediate 4 of scheme 11(a)] (0.7 g, 0.0026 mol) and 1,4- dioxane. To the same flask, hydrochloric acid in 1,4-dioxane (10 mL) was added. The reaction mixture was stirred at RT for 3 h. The volatiles were evaporated under reduced pressure to get solid. The solid was washed with diethyl ether to get the title compound [0.4 g, 96 percent]. LC-MS: 169.9 [M+H]+.
95%
With hydrogenchloride In 1,4-dioxane at 20℃; for 0.5 h;
A solution of intermediate 2 (15 g, 55.6 mmol) in a 4M solution of HCl in 1 ,4-dioxane (100 mL) was stirred at room temperature for 30 minutes. The solvent was evaporated in vacuo to yield 10 g (95percent) of intermediate 3 as a yellow powder which was used in the next step without further purification.
With sodium hydrogencarbonate; In ethanol; at 80℃; for 2.5h;
Step iv: tert-butyl 2-amino-4-oxo-6,7-dihvdrothiazolo[5,4-clpyridine-5(4H)-carboxylate To a 50 mL round bottom flask, were added tert-butyl 3-bromo-2,4-dioxopiperidine-l- carboxylate (1 g, 0.0034 mol), thiourea (0.287 g, 0.0038 mol), sodium bicarbonate (0.317 g, 0.0038 mol) and ethanol (15 mL). The reaction mixture was stirred at 80 C for 2.5 h. The volatiles were evaporated under reduced pressure to get residue. The residue was partitioned between ethyl acetate and water. The organic layer was separated, washed with brine and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain the title compound [0.7 g, 76 %]. NMR (300 MHz, CDsOD): delta 4.05 (t, 2H), 2.83 (t, 2H), 1.52 (s, 9H).
66%
With sodium hydrogencarbonate; In ethanol; at 80℃; for 2.5h;
A mixture of intermediate 1 (25 g, 85.6 mmol), thiourea (6.5 g, 85.6 mmol) and NaHC03 (7.2 g, 85.6 mmol) in EtOH (400 mL) was heated at 80C for 2.5 hours. The reaction mixture was then cooled to room temperature and the solids were filtered off. The filtrate was evaporated in vacuo to give a residue that was crystallized from EtOH. The yellow crystals thus obtained were filtered off and dried to yield 15 g (66%) of intermediate 2.
66%
With sodium hydrogencarbonate; In ethanol; at 80℃; for 2.5h;
A mixture of intermediate 2 (25 g, 85.6 mmol), thiourea (6.5 g, 85.6 mmol) and NaHC03 (7.2 g, 85.6 mmol) in EtOH (400 mL) was heated at 80C for 2.5 hours. The reaction mixture was then cooled to room temperature and the solids were filtered off. The filtrate was evaporated in vacuo to give a residue that was crystallized in EtOH. The yellow crystals thus obtained were filtered off and dried to yield 15 g (66%) of intermediate 3.
With sodium hydrogencarbonate; In ethanol; at 80℃; for 2.5h;
A mixture of intermediate 2 (25 g, 85.6 mmol), thiourea (6.5 g, 85.6 mmol) and NaHCO3 (7.2 g, 85.6 mmol) in EtOH (400 mL) was heated at 80 C. for 2.5 hours. The reaction mixture was then cooled to room temperature and the solids were filtered off. The filtrate was evaporated in vacuo to give a residue that was crystallized in EtOH. The yellow crystals thus obtained were filtered off and dried to yield 15 g (66%) of intermediate 3.
200 mg
With sodium hydrogencarbonate; In ethanol; at 80℃; for 2.0h;
[0148] Method H-Step d: Tert-butyl 2-amino-4-oxo-6,7-dihydrothiazolo[5,4-c]pyridine- 5(4H)-carboxylate [0149] A mixture of tert-butyl 3-bromo-2,4-dioxopiperidine-l-carboxylate (292 mg, 1 mmol), thiourea (76 mg, 1 mmol) and NaHCC>3 (84 mg, 1 mmol) in ethanol (4 mL) was heated at 80C for 2 hours. The reaction mixture was then cooled to room temperature and the solids were filtered off. The filtrate was evaporated in vacuo to give a residue that was crystallized from EtOH. The white crystals thus obtained were filtered off and dried to yield 200 mg (74.3% for two steps). *H NMR (400 MHz, DMSO-i5) delta 8.08 (s, 2H), 3.89 (t, J Hz, 2H), 2.75 (t, / = 6.4 Hz, 2H), 1.44 (s, 9H).
With hydrogenchloride; In 1,4-dioxane; at 20℃; for 3.0h;
Step i: 2-amino-6,7-diriydrothiazolor5,4-clpyridin-4(5H)-one To a 50 mL round bottom flask, were added tert-butyl 2-amino-4-oxo-6,7-dihydrothiazolo[5,4- c]pyridine-5(4H)-carboxylate [intermediate 4 of scheme 11(a)] (0.7 g, 0.0026 mol) and 1,4- dioxane. To the same flask, hydrochloric acid in 1,4-dioxane (10 mL) was added. The reaction mixture was stirred at RT for 3 h. The volatiles were evaporated under reduced pressure to get solid. The solid was washed with diethyl ether to get the title compound [0.4 g, 96 %]. LC-MS: 169.9 [M+H]+.
95%
With hydrogenchloride; In 1,4-dioxane; at 20℃; for 0.5h;
A solution of intermediate 2 (15 g, 55.6 mmol) in a 4M solution of HCl in 1 ,4-dioxane (100 mL) was stirred at room temperature for 30 minutes. The solvent was evaporated in vacuo to yield 10 g (95%) of intermediate 3 as a yellow powder which was used in the next step without further purification.
With hydrogenchloride; In 1,4-dioxane; at 20℃; for 0.5h;
A solution of intermediate 3 (15 g, 55.6 mmol) in a 4M solution of HCl in 1,4-dioxane (100 mL,) was stirred at room temperature for 30 minutes. The solvent was evaporated in vacuo to yield 10 g (95%) of intermediate 4 as a yellow powder which was used in the next step without further purification.
With hydrogenchloride; In 1,4-dioxane; at 20℃; for 0.5h;
A solution of intermediate 3 (15 g, 55.6 mmol) in a 4M solution of HCl in 1,4-dioxane (100 mL) was stirred at room temperature for 30 minutes. The solvent was evaporated in vacuo to yield 10 g (95%) of intermediate 4 as a yellow powder which was used in the next step without further purification.
With copper(ll) bromide; isopentyl nitrite; In N,N-dimethyl-formamide; at 0 - 40℃; for 0.5h;
[0150] Method H-Step e: Tert-butyl 2-bromo-4-oxo-6,7-dihydrothiazolo[5,4-c]pyridine- 5(4H)-carboxylate [0151] To a solution of isopentyl nitrite (176 mg, 1.5 mmol) and CuBr2 (268 mg, 1.2 mmol) in 2.5 mL of DMF was added tert-butyl 2-amino-4-oxo-6,7-dihydrothiazolo[5,4-c]pyridine- 5(4H)-carboxylate (269 mg, 1 mmol) at 0 C. The mixture was stirred at 40 C for 30 min. It was added to 20 mL of brine and extracted with ethyl acetate (30 mLx2). The combined organics were washed with brine (10 mLx2) and dried over Na2S04. Concentrated and purified by silica gel column chromatography (petroleum ether: EtO Ac = 20:1) to give the title compound (150 mg, 45%) as a white solid. *H NMR (400 MHz, CDC13) delta 4.12 (t, J = 6.4 Hz, 2H), 3.10 (t, / = 6.4 Hz, 2H), 1.56 (s, 9H).
tert-butyl 2-(methylthio)-5-oxo-7,8-dihydropyrido[4,3-d]pyrimidine-6(5H)-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
[0194] Method L-Step a: Tert-butyl 2-(methylthio)-5-oxo-7,8-dihydropyrido[4,3- d]pyrimidine-6(5H)-carb [0195] Tert-butyl 2,4-dioxopiperidine-l-carboxylate (2.45 g, 11.5 mmol) was dissolved in 10 mL of DMF-DMA. The mixture was stirred at 100 C for 40 min. After cooling, the mixture was evaporated and added to the solution of 2-methyl-2-thiopeudourea sulfate (2.6 g, 13.8 mmol) and sodium ethanolate (1.88 g, 27.6 mmol) in 30 mL of ethanol. The reaction mixture was stirred at room temperature for 0.5 h and then heated to 80 C overnight. After the mixture was evaporated, the residue was diluted with brine (30 mL) and extracted with ethyl acetate (30 mLx2). The combined organics were dried over Na2S04 and concentrated to obtain the crude compound (2.5 g) as a brown oil that was used without further purification in the subsequent step. *H NMR (300 MHz, CDC13) delta 9.09 (s, 1H), 4.04 (t, J = 6.4 Hz, 2H), 3.07 (t, J = 6.4 Hz, 2H), 2.61 (s, 3H), 1.58 (s, 9H).
tert-butyl 2-(2-(4-(ethylsulfonyl)phenyl)acetamido)-4-oxo-6,7-dihydrothiazolo[5,4-c]pyridine-5(4H)-carboxylate[ No CAS ]
Yield
Reaction Conditions
Operation in experiment
22%
With benzotriazol-1-ol; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; In dichloromethane; at 20℃; for 12.0h;Inert atmosphere;
Step v: tert-butyl 2-(2-(4-(ethylsulfonyl)phenyl)acetamido)-4-oxo-6,7-dihydrothiazolor5,4- clpyridine-5(4H)-carboxylate To a 25 mL round bottom flask, were added tert-butyl 2-amino-4-oxo-6,7-dihydrothiazolo[5,4- c]pyridine-5(4H)-carboxylate (0.25 g, 0.0009 mol), 2-(4-(ethylsulfonyl)phenyl)acetic acid (0.318 g, 0.0014 mol) and dichloromethane (10 mL). To the same flask, EDCI.HCl (0.265 g, 0.0014 mol) and HOBt (0.188 g, 0.0014) were added. The reaction mixture was stirred under nitrogen atmosphere at RT for 12 h. The reaction mixture was diluted with dichloromethane and washed with water. The organic layer was separated, washed with water followed by saturated aqueous sodium bicarbonate and dried over anhydrous sodium sulfate. The solvent was evaporated under reduced pressure to obtain crude product. The crude product was purified by column chromatography using 60-120 silica gel and 100 % ethyl acetate to get the title compound [O.lg, 22 %]. LCMS: 379.8 [M-Boc+H]+.
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