Originator
Domar ,Zambeletti, Italy,1975
Uses
Pinazepam is a is a benzodiazepine. Pinazepam possesses anxiolytic, anticonvulsant, sedative and skeletal muscle relaxant properties. Pinazepam is less toxic than Diazepam.
This is a contolled substance (depressant). Anxiolytic.
Manufacturing Process
46.3 g (0.2 mol) of 2-amino-5-chlorobenzophenone were dissolved in 100 ml (1.28 mols) of propargyl bromide and the mixture refluxed for 4 hours. Thereafter, the whole was evaporated to dryness and the residue recrystallized from methanol to give 32.4 g (60.2%) of the desired 2-propargylamino-5chlorobenzophenone; melting point 92°C to 93°C.
2.7 g (0.01 mol) of the 2-propargylamino-5-chlorobenzophenone obtained as above and 2.23 g (0.01 mol) of phthalimidoacetyl chloride were added to 30 ml of chloroform and the whole was refluxed overnight. Thereafter, the reaction mixture was evaporated to dryness and the residue recrystallized from methanol to give 2.66 g (58.3%) of the desired 2-(Npropargyl)phthalimidoacetamide-5-chlorobenzophenone. Melting point: 176°C.
A suspension of 22.8 g (0.05 mol) of 2-(N-propargyl)-phthalimidoacetamido5-chlorobenzophenone in 250 ml ethanol containing 7.5 g hydrazine hydrate (0.15 mol) was heated under reflux for 2 hours, at the end of which time the reaction mixture was set aside overnight at ambient (25°C) temperature. Thereafter, the crystalline phthalyl hydrazide which had precipitated out was removed by filtration and washed with 3 x 50 ml aliquots of chloroform. The filtrate and washings were diluted with water and exhaustively extracted with chloroform. The chloroform extract was then evaporated and the residue washed with 100 ml hexane to promote crystallization. The crude 7-chloro-1propargyl-3H-1,4-benzodiazepine-2(1H)-one was recrystallized from a methanol-water mixture to give 10.5 g (71.4%) of the pure product. Melting point: 140°C to 142°C.
