Abstract
4-(4-Methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-furan-dione (1) reacted with N-aryl substituted phenyl-hydrazones (3a-h) via the p,p'-dimethoxydibenzoylketene intermediate (2) giving the proponohydrazide derivatives (5a-h). In addition, compounds 5a-h were converted into corresponding pyrazolone derivatives (7i, j) by the reactions of hydrolysis in acidic solution. The structures of these compounds were determined by C-13 NMR, H-1 NMR and IR spectroscopic data and elemental analysis.