[7-chloro-5-(2-fluorophenyl)-2,3-dihydro-1H-1,4-benzodiazepin-2-yl]methanamine

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: U.S Pat. No. 4,280,957 (hereinafter the '957 patent) describes a synthetic process for preparing midazolam, which is depicted in Scheme 2 below. This process includes reacting 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-bezodiazepine (II) with acetic anhydride in dichloromethane to produce 2-acetamido-methyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-bezodiazepine (III). The latter is heated with polyphosphoric acid at 150° C. to produce 8-chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of formula (IV), which is purified by column chromatography. Compound IV is then mixed with toluene and manganese dioxide and heated to reflux to afford midazolam base, which is crystallized from ether to yield a product with mp of 152-154° C.

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

Procedure: U.S Pat. No. 4,280,957 (hereinafter the '957 patent) describes a synthetic process for preparing midazolam, which is depicted in Scheme 2 below. This process includes reacting 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-bezodiazepine (II) with acetic anhydride in dichloromethane to produce 2-acetamido-methyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-bezodiazepine (III). The latter is heated with polyphosphoric acid at 150° C. to produce 8-chloro-6-(2-fluorophenyl)-3a,4-dihydro-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of formula (IV), which is purified by column chromatography. Compound IV is then mixed with toluene and manganese dioxide and heated to reflux to afford midazolam base, which is crystallized from ether to yield a product with mp of 152-154° C.

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

Procedure: (iv) 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a] [1.4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: iv. 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro- 5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150°C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo-[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-metnhyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: iv. 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro- 5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150°C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo-[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-metnhyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: (iv) 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: (iv) 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C. for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo-[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: (iv) 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7 -chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methyl-4H-imidazo-[1,5-a] [1,4]benzodiazepine. A mixture of this material with 500 m1 of toluene and 30 g of manganese dioxide was heated to reflux of 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo [1,5-a] [1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recyrstallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated

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

Procedure: iv. 7 ml of acetic anhydride were added to a solution of 6.16 g of crude 2-aminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine in 200 ml of methylene chloride. The solution was layered with 200 ml of saturated aqueous sodium bicarbonate and the mixture was stirred for 20 minutes. The organic layer was separated, washed with sodium bicarbonate solution, dried over sodium sulphate and evaporated to leave 6.2 g of resinous 2-acetaminomethyl-7-chloro-2,3-dihydro-5-(2-fluorophenyl)-1H-1,4-benzodiazepine. This material was heated with 40 g of polyphosphoric acid at 150° C for 10 minutes. The cooled mixture was dissolved in water, made alkaline with ammonia and ice and extracted with methylene chloride. The extracts were dried and evaporated and the residue (5.7 g) was chromatographed over 120 g of silica gel using 20% methanol in methylene chloride. The clear fractions were combined and evaporated to yield resinous 8-chloro-3a,4-dihydro-6-(2-fluorophenyl)-1-methy,-4H-imidazo-[1,5-a][1,4]benzodiazepine. A mixture of this material with 500 ml of toluene and 30 g of manganese dioxide was heated to reflux for 1.5 hours. The manganese dioxide was separated by filtration over Celite. The filtrate was evaporated and the residue crystallised from diethyl ether to yield 8-chloro-6-(2-fluorophenyl)-1-methyl-4H-imidazo[1,5-a][1,4]benzodiazepine of melting point 152°-154° C. An analytical sample was recrystallised from methylene chloride/hexane. The organic layer was separated washed with sodium bicarbonate solution dried over sodium sulphate evaporated