Zur Synthese kondensierter Heterocyclen aus Malonsäurederivaten

摘要

The reaction of 2-substituted benzoxazoles (1 a, 1 c), benzothiazoles (1 b, 1 d) and benzoselenazole (1 e) with 2,4,6-trichlorophenyl malonates (2 a, b) gives—depending on the nature of the alkyl substituent—the fused hydroxypyridones3or their hydroxypyrono derivatives. 2,5-Dimethyl-thiadiazol5reacts in the same way with2 ayielding the pyrono-thiadiazolopyrid