Acetic Acid → 5,10-Dihydro-5-(4-amino-2-chlorobenzoyl)-4H-pyrazolo[5,1-c][1,4]benzodiazepine

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Reaction Steps

A mixture of 0.553 g of 5,10-dihydro-5-(4-nitro-2-chlorobenzoyl)-4H-pyrazolo[5,1-c][1,4]benzodiazepine, 1.70 g of stannous chloride dihydrate in 20 ml of ethanol is heated at 70°-80° C. for 1 hour. The mixture is chilled, made basic with 1M NaHCO3 and then stirred at room temperature for 0.5 hour. The mixture is brought to pH 5 with acetic acid and extracted (several times) with ethyl acetate. The combined extracts are dried (Na2SO4) and passed through a pad of hydrous magnesium silicate. The filtrate is evaporated and the residue dissolved in dichloromethane and the solution passed through a thin pad of hydrous magnesium silicate. The filtrate is evaporated in vacuo to give 0.40 g of a glass, m.p. 98°-117° C.; Anal. Calc'd: C, 62.9; H, 4.7; N, 16.3; Cl, 11.6. Found: C, 62.4; H, 4.3; N, 15.6; Cl, 11.7.

Provenance & Evidence