Synthesis of substituted 2,3,5,6,7,8-hexahydropyrazolo[4,3-d][1,2]diazepine-8-carboxylates

Substituted 2,3,5,6,7,8-hexahydropyrazolo[4,3-d][1,2]diazepine-8-carboxylates were obtained from ethyl (2E)-3-(dimethylamino)-2-{(4Z)-4-[(dimethylamino)-methylidene]-5-oxo-1-phenyl-4,5-dihydro-1H-pyrazol-3-yl}propenoate, via substitution of both dimethylamino groups with 1,2-dialkylhydrazines.