Pyrrolo [3,4-e][1,2,3]triazolo[1,5-a]pyrimidine and pyrrolo[3,4-d][1,2,3]triazolo[1,5-a]pyrimidine. New tricyclic ring systems of biological interest

Derivatives of the new ring system pyrrolo[3,4-e][1,2,3] triazolo[1,5-a]pyr imidine 6 were prepared in high yields in one step by reaction of 3-azidopy rrole 3 and substituted acetonitriles. Compound 6b rearranged, upon heating in dimethyl sulfoxide in the presence of water, to pyrrolo[3,4-d]1,2,3]tri azolo[1,5-a]pyrimidine 7.