Heterocycles from aroylacetic aldehydes and SH-containing hydrazides
В. В. ПакальнисSt. Petersburg State University, St. Petersburg, 198504, RussiaИ. В. ЗероваSt. Petersburg State University, St. Petersburg, 198504, RussiaS. I. YakimovichSt. Petersburg State University, St. Petersburg, 198504, RussiaА. Yu. ErshovInstitute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, RussiaИ. В. Лагода
2009en
ABI
Abstract
Condensation products of aroylacetic aldehydes with hydrazides of thioglycolic, 3-mercaptopropionic and 2-mercaptobenzoic acids exist in cyclic 1,3,4-thiadiazine, 1,3,4-thiadiazepine, or 1,3,4-benzothiadiazepine forms arising at the intramolecular addition of the mercapto group to the C=N bond of the initially formed hydrazone tautomer. The appearance of an alternative 5-hydroxy-2-pyrazoline form is favored by introduction of a strong electron-acceptor substituent into the aromatic ring of the 1,3-ketoaldehyde or by going over to benzoylacetone derivatives. In solutions the derivatives of aroylacetic aldehydes and of benzoylacetone show no tendency to tautomeric transition into linear hydrazine or enhydrazine forms.
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