Study on the Reactions of 3‐Benzoyl‐2,4,5‐pyrrolidinetrione with aliphatic diamines, phenylhydrazine, semicarbazide and guanidine derivatives

Abstract

3‐Benzoyl‐2,4,5‐pyrrolidinetrione (1a,b) with aliphatic diamines, phenylhydrazine, semicarbazide, and guanidine derivatives yields mono and binary salts (4, 7, 10, 11‐14), enamines (2, 3), imine (5), pyrrolo[3,4‐c]pyrazole (6) and pyrrolo [3,4‐e][1,4]diazepine (8), respectively. The influence of the reagents basicity on the route of cyclocondensation is studied.

Pyrrolidinetrione Derivatives: Synthesis And Applications in Heterocyclic Chemistry

“…Pyrrolo[3,4-c]pyrazole, Pyrrolo[3,4-c]-1,4-diazepine and Pyrrolo[3,4-f]-1,5-diazocine A general route to pyrrolo[3,4-c]pyrazoles 49 and 50, 51,52 pyrrolo[3,4-e]-1,4-diazepines 51 and 52,[53][54][55] as well as pyrrolo[3,4-f]-1,5-diazocines 53 and 54 56 is based on regioselective attack of binucleophiles at positions C-6 and C-3 under conditions excluding competitive formation of the appropriate salts 48. The pyrrolo[3,4-c]pyrazole derivatives 49 and 50 were obtained by cyclocondensation of the appropriate pyrrolidinetrione with phenyl hydrazine in boiling ethanol.51,52 Pyrrolo[3,4-f]-1,4-diazepines 51 and 52 were prepared in a similar way by reaction of 22 or 33 with ethylene diamine, but at room temperature in ethanol. This method also facilitated the synthesis of diazocine derivatives 53 and 54, but the presence of catalytic amounts of toluene sulfonic acid was necessary.56 In addition, this facile procedure was very useful for the synthesis of 1,5-perhydrobenzodiazepine derivatives 55 and 56, obtained by heterocyclization of 22 or 33 with trans-1,2-diaminocyclohexane in a boiling mixture of DMF-ethanol (Scheme 18) 58.…”