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 pyrrolo3,4‐e]1,2,3] triazolo1,5‐a]pyrimidine 6 were prepared in high yields in one step by reaction of 3‐azidopyrrole 3 and substituted acetonitriles. Compound 6b rearranged, upon heating in dimethyl sulfoxide in the presence of water, to pyrrolo3,4‐d]1,2,3]triazolo‐1,5‐a]pyrimidine 7.