1-piperazin-1-ylethanone;hydrochloride

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-7-[3-tert-Butoxycarbonylamino-4-(2,4,5-trifluoro-phenyl)-butyryl]-3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-carboxylic acid 2a (150 mg, 0.27 mmol), 1-piperazin-1-yl-ethanone hydrochloride (90 mg, 0.54 mmol) and bis(2-oxo-3-oxazolidinyl)phosphonic chloride (0.138 g, 0.54 mmol) were dissolved in 8 mL of dichloromethane under stirring, and triethylamine (0.25 mL, 1.62 mmol) was then added to the solution. The reaction mixture was reacted at room temperature overnight and monitored by thin layer chromatography until the disappearance of the starting materials. The reaction mixture was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound (R)-[3-[1-(4-acetyl-piperazine-1-carbonyl)-3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl]-3-oxo-1-(2,4,5-trifluoro-benzyl)-propyl]-carbamic acid tert-butyl ester 17a (80 mg, yield 45%) as a white solid. The reaction mixture was reacted at room temperature overnight The reaction mixture was concentrated under reduced pressure The resulting residue was purified by silica gel column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1-Acetyl-4-chlorocarbonylpiperazine can be prepared by the action of phosgene (9.9 g.) on 1-acetylpiperazine (25.6 g.) in anhydrous toluene (75 cc.) for 1 hour at 2° C. The 1-acetylpiperazine hydrochloride formed during the reaction is filtered off and washed with anhydrous toluene (50 cc.). The toluene filtrate is evaporated to dryness under reduced pressure (20 mm.Hg) to give 1-acetyl-4-chlorocarbonylpiperazine (14.0 g.) in the form of an oil.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-7-[3-tert-Butoxycarbonylamino-4-(2,4,5-trifluoro-phenyl)-butyryl]-3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-carboxylic acid 2a (150 mg, 0.27 mmol), 1-piperazin-1-yl-ethanone hydrochloride (90 mg, 0.54 mmol) and bis(2-oxo-3-oxazolidinyl)phosphonic chloride (0.138 g, 0.54 mmol) were dissolved in 8 mL of dichloromethane under stirring, and triethylamine (0.25 mL, 1.62 mmol) was then added to the solution. The reaction mixture was reacted at room temperature overnight and monitored by thin layer chromatography until the disappearance of the starting materials. The reaction mixture was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound (R)-[3-[1-(4-acetyl-piperazine-1-carbonyl)-3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl]-3-oxo-1-(2,4,5-trifluoro-benzyl)-propyl]-carbamic acid tert-butyl ester 17a (80 mg, yield 45%) as a white solid. The reaction mixture was reacted at room temperature overnight The reaction mixture was concentrated under reduced pressure The resulting residue was purified by silica gel column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 1-Acetyl-4-chlorocarbonylpiperazine can be prepared by the action of phosgene (9.9 g.) on 1-acetylpiperazine (25.6 g.) in anhydrous toluene (75 cc.) for 1 hour at 2° C. The 1-acetylpiperazine hydrochloride formed during the reaction is filtered off and washed with anhydrous toluene (50 cc.). The toluene filtrate is evaporated to dryness under reduced pressure (20 mm.Hg) to give 1-acetyl-4-chlorocarbonylpiperazine (14.0 g.) in the form of an oil.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (R)-7-[3-tert-Butoxycarbonylamino-4-(2,4,5-trifluoro-phenyl)-butyryl]-3-trifluoromethyl-5,6,7,8-tetrahydro-imidazo[1,5-a]pyrazine-1-carboxylic acid 2a (150 mg, 0.27 mmol), 1-piperazin-1-yl-ethanone hydrochloride (90 mg, 0.54 mmol) and bis(2-oxo-3-oxazolidinyl)phosphonic chloride (0.138 g, 0.54 mmol) were dissolved in 8 mL of dichloromethane under stirring, and triethylamine (0.25 mL, 1.62 mmol) was then added to the solution. The reaction mixture was reacted at room temperature overnight and monitored by thin layer chromatography until the disappearance of the starting materials. The reaction mixture was concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography to obtain the title compound (R)-[3-[1-(4-acetyl-piperazine-1-carbonyl)-3-trifluoromethyl-5,6-dihydro-8H-imidazo[1,5-a]pyrazin-7-yl]-3-oxo-1-(2,4,5-trifluoro-benzyl)-propyl]-carbamic acid tert-butyl ester 17a (80 mg, yield 45%) as a white solid. The reaction mixture was reacted at room temperature overnight The reaction mixture was concentrated under reduced pressure The resulting residue was purified by silica gel column chromatography

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: In 2 ml of methylene chloride was suspended 70 mg of N-acetylpiperazine monohydrochloride, and 80 mg of triethylamine was added thereto to form a solution. Subsequently, 200 mg of ethyl 1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-7-(2,4,6-triisopropylbenzenesulfonyloxy)-1,8-naphthyridine-3-carboxylate was added thereto, and the resulting mixture was subjected to reaction at room temperature for 2 hours. To the reaction mixture were added 8 ml of methylene chloride and 10 ml of water, and the organic layer was separated, washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution, and then dried over anhydrous magnesium sulfate. The solvent was removed by distillation under reduced pressure, and to the residue thus obtained was added 5 ml of diethyl ether, after which the crystals thus deposited were collected by filtration to obtain 140 mg (yield 93.1%) of ethyl 7-(4-acetyl-1-piperazinyl)-1-(2,4-difluorophenyl)-6-fluoro-1,4-dihydro-4-oxo-1,8-naphthyridine-3-carboxylate having a melting point of 217°-219° C. The physical properties of this compound were identical with those of the compound obtained in Example 39. was added to form a solution the resulting mixture was subjected to reaction at room temperature for 2 hours the organic layer was separated washed successively with 10 ml of water and 10 ml of saturated aqueous sodium chloride solution dried over anhydrous magnesium sulfate The solvent was removed by distillation under reduced pressure to the residue thus obtained after which the crystals thus deposited were collected by filtration