Synthesis of novel pyrazolino[3', 4':5,4]cyclopent[b]indoles

Several new pyrazolino[3',4';5,4]cyclopent[b]indoles 2a-e have been synthesized from the reaction of 2-(4'-methoxy)benzyl-idene-1-ox-1H, 8H-2,3-dihydrocyclopent[b]indoles la-e with hydrazine hydrate in ethanol in good yield.