A Novel Synthesis of Imidazo[2,1-d][1,2,4]triazine and Imidazo[2,1-d][1,2,5]triazepine Derivatives via Ketene-N,N-acetal

Abstract

The ketene-S,S-acetal Iwas preparedunder phase-transfer catalysis (PTC) in benzene-carbonate two phase system using tetrabutylammonium bromide as thecatalyst. Upon treatment with 1,2-diaminoethane, followed by hydrolysis with sodium methoxide, I gave 2-(2-oxopropylidene)imidazoline III. Bromination of III and replacement of bromine by hydrazine afforded 2-(1-hydazino-1,2-oxopropylidene)imidazoline V. Compound V was used as a precursor for the preparation of the previously unreported fused nitrogen heterocyclic ring system of imidazotriazine VI, VIII, XI, XII and imidazotriazepine IX, X.

Key Words:

• Imidazotriazine
• Imidazotriazepine
• Ketene-N,N-acetal