7
1. 8. 1997.
Transformation of 5-Oxo Substituted Fused Pyran-2-ones. Lactam Versus Hydrazone Formation
Abstract 6, 7-Dihydrocyclopenta[b]pyran-2, 5-dione 1 was converted with hydrazines to fused pyridine-2(1H)-ones of type a. In contrast, 2H-1-benzopyran-2, 5-diones 2–4 gave under the same reaction conditions 5-hydrazonobenzopyrans of type b. Calculated heats of formation matched experimental findings.