Hydrazinecarboxaldehyde → Estazolam

Participants

Reaction Steps

A mixture of 5.74 g. (0.020 mole) of 7-chloro-1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-thione, 3.6 g. (0.060 mole) of formic acid hydrazide and 200 ml. of 1-butanol was refluxed for 3.75 hours with a slow stream of nitrogen bubbling through the mixture. The mixture was concentrated, the residue was suspended in water, and the suspension was filtered. The filter cake consisted principally of unchanged starting material. The filtrate was concentrated, ethyl acetate and Skellysolve B hexanes being added during the concentration, giving crude product (2.54 g.) of melting point 220.5°-225° C. Recrystallization of this material from ethyl acetate-Skellysolve B hexanes gave 8-chloro-6-phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepine of melting point 228°-229° C. The ultraviolet spectrum (ethanol) had end absorption λ max. 222 (ε = 40,950) and inflections at 245 (ε = 16,200) and 285 mμ(ε = 3,500).

Provenance & Evidence