Anisylidine pyruvic acid in heterocyclic synthesis

A series of substituted pyran, pyridine, thiin (3), (4), (5) and (6) were prepared from anisylidine pyruvic acid (1a). The indenopyran (7) was also prepared from (1a) via Michael addition reaction. Compound (1a) condensed with o-phenylenediamine and o-aminophenol to give (8) and (9). Reaction of (1a) with thiosemicarbazide afforded (10) which cyclized to give the triazine (11). Compound (1b) was subjected to react with o-phenylenediamine, o-aminophenol and diamino-arylazopyrazole derivatives to yield the Schiff bases (12, 13) and (14) respectively. Addition of malononitrile (1 mole) to (1b) gave (15) while addition of (2 moles) of malononitrile gave (16). Reaction of (1b) with urea yielded the pyrrolopyrimidine (17). The structures of the products were confirmed by their correct analytical data.