SYNTHESIS OF IMIDAZO[4,5-C] AND TRIAZEPINO|6,5-C]CINNOLINES

Document Type : Original Article

Authors

Department of Organic Chemistry, Faculty of Pharmacy, Cairo University, Kasr-El-Ainy 11562, Cairo, Egypt.

Abstract

Hofmann degradation of 4-amino-8-methylcinnoline-3-carboxamide (1) gave 3,4-diaminocinnoline 2 which was employed to prepare imidazo and 2-substitutedimidazo[4,5-c]cinnolines 3. On the other hand, reaction of 4-aminocinnoline-3-carboxylic acid hydrazides 4 with ethyl chloroformate or potassium O-ethyl dithiocarbonate afforded 2,3,4,5-tetrahydro-1H-1,2,4- triazepino[6,5-c]cinnoline-2,5-diones 6 and the corresponding 2-thiones 7, respectively. Furthermore, reacting 4 with excess orthoesters gave mixtures of 4,5-dihydro-1H-1,2,4-triazepino[6,5-c]cinnolin-5-ones 9 and 3-(ethoxyalkylidenamino) pyrimi-do[5,4-c] cinnoline-4-ones 10 which were separated and characterized.