Abstract
Some new fused heterobicyclic systems, such as thiazolo[3,2-a]-pyrimidin-5-one (3), 2,3-tetrahydrothiazolo[3,2-a]pyrimidin-5-one (5), 2,4-tetrahydrothiazino[3,2-a]pyrimidin-3,6-dione (6), 3-dihydrothiazino[3,2-a]pyrimidin-2,4,6-trione (7), 3-arylidenethiazino[3,2-a]pyrimidin-2,4,6-trione (8) and/or the related nitrogen compounds, such as 2,3-tetrahydroimidazolo[3,2-a]-pyrimidin-5-one (9), 1-aryl-2,3-tetra-hydroimidazolo[3,2-a]pyrimidin-5-one (11), quinazolino[3,2-a]-pyrimidin-6,8-dione (12) and 3-mercapto-1,2,4-triazolo[4,3-a]pyrimidin-5-one (14) have been synthesized by the interaction of 2-mercapto-4-arylidene-5-cyanopyrimidin-6(1H)one (1) with α,β-bifunctional nitrogen, oxygen and/or sulfur compounds. The structures have been characterized by elemental analyses, IR, UV, 1H NMR and mass spectral data. Some newly prepared compounds revealed a moderate effect on the activity of cellobiase produced by Aspergillus nidulans.