Selective and efficient transformation of 5,6,7,8-tetrahydro-2H-1-benzopyran-2,5-diones with hydrazines to 5-hydrazono-2H-1-benzopyran-2-ones and quinoline-2,5-diones. Extension to related systems

✍ Scribed by Polonca Trebše; Slovenko Polanc; Marijan Kočevar; Tomaž Šolmajer; Simona GoličGrdadolnik

• Book ID: 104207427
• Publisher: Elsevier Science
• Year: 1997
• Tongue: French
• Weight: 474 KB
• Volume: 53
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(96)01050-2

✦ Synopsis

Highly selective transformations of 5,6,7,8-tetrahydro-2H-l-benzopyran-2,5-diones I-3 and 5acetyl-2H-pyran-2-one derivative 14 with hydrazides, phenylhydrazines and heterocyclic hydrazines as nitrogen-containing nucleophiles were investigated. The benzopyran-2,5-diones were converted to the corresponding 5-hydrazono-2H-I-benzopyrans of type a and further to quinolines of type b. In the 2Hpyran-2-one series the corresponding hydrazone 15 and pyrazole 16 were obtained. In some cases, using interatomic distances obtained from the NOESY spectra, conformational analysis was performed and heats of formation were calculated.