Dimroth rearrangement-based synthesis of novel derivatives of [1,3]selenazolo[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine as a new class of selenium-containing heterocyclic architecture.

As a part of our ongoing endeavor towards developing novel heterocyclic architectures, a number of novel Se-containing tricyclic heterocycles of the type [1,3]selenazolo[5,4-e][1,2,4]triazolo[1,5-c]pyrimidine have been synthesized through heteroannulation of a newly produced hydrazino derivative of selenazolo[4,5-d]pyrimidine with either orthoesters or carbon disulfide in pyridine followed by S-alkylation. Moreover, the multistep protocol employed in this investigation provides a new insight into the Dimroth rearrangement in both acidic and basic media as a means for the cyclocondensation of triazole on the selenazolopyrimidine framework leading to selenazolotriazolopyrimidines. The synthesis of new derivatives of novel selenazolotriazolopyrimidines via Dimroth rearrangement in both acidic and basic media is presented.