SYNTHESIS OF NOVEL HETEROAROMATIC POLYFUSED AS-TRIAZINES BY RING TRANSFORMATION

Ring transformation of the tricyclic furo-fused as-triazinium salt 1 in the presence of nucleophilic reagents (e.g. sodium hydrogensulfide, sodium salts of malonic ester, ethyl cyanoacetate, acetylacetone, dimedone, or malononitrile) leads to the two new heteroaromatic ring systems thieno[2,3-e]pyrido[1,2-b]-as-triazinium salt (5) and differently substituted cyclopenta[e]pyrido[1,2-b]-as-triazine compounds (8, 9, 10, 11, and 13).