Synthesis of isochroman-fused pyrazolone and pyrimidine derivatives

Unsubstituted 5 , and 2-aryl- 6a-c , or 2-(2-benzothiazolyl)-substituted 1,3-dihydroisochromano[4,3-c]pyrazol-3(2H)-ones 7a-f were prepared by the reactions of 3-ethoxyoxalyl- 2 , or 3-ethoxycarbonylisochroman-4-one 3 with hydrazine derivatives. The reactions with amidines gave 2-substituted 4-hydroxyisochromano[4,3-d]-pyrimidines 8a-c .