Collect. Czech. Chem. Commun. 1984, 49, 1529-1535

Synthesis and reactions of furocondensed systems containing indole skeleton

Anna Koreňová, Alžbeta Krutošíková, Miloslava Dandárová and Jaroslav Kováč

Department of Organic Chemistry, Slovak Institute of Technology, 817 37 Bratislava


The new 1,2,4-triazolo[3''', 4''':6'', 1'']-1,2,4-triazino[4'', 5'':4,5]furo[3,2-b]indoles V and 1-acetyl-9H-pyrrolo[2',3':4,5]furo[3,2-b]indole (IX) were prepared from 1,9-dihydropyrrolo[2',3':4,5]furo[3,2-b]indole-2-carboxhydrazide I and 2-(2-nitrophenyl)-4H-furo[3,2-b]pyrrole-5-carboxylic acid, respectively. Compound I gave with triethyl orthoformate or with triethyl orthoacetate 1,2-dihydro-1,2,4-triazino[4'',5'':1',5']pyrrolo[2',3':4,5]furo[3,2-b]indol-1-one or its methyl analogue II. Substances II afforded with phosphorus pentasulfide thiones III reacting with hydrazine to furnish IV. Cyclization of the latter with triethylorthoformate or orthoacetate led to V. Compounds II and III can also be obtained by a deoxygenative cyclization of VI and VII with triethyl phosphite.