Cyclization of 1,5-dinitrile systems with hydrogen halides: A search for the undetected key tautomer

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• 作者：Teixidó ; Jordi ; Borrell ; José ; I. ; Serra ; Blanca ; Colominas ; Carles ; Batllori ; Xavier ; et. al.
• 刊名：Tetrahedron
• 出版年：1997
• 出版时间：March 24, 1997
• 年：1997
• 卷：53
• 期：12
• 页码：4487-4496
• 全文大小：479 K

文摘

The ¹³C NMR spectra of the pyridones 7a-d recorded in DMSO-d₆ show three groups of signals which correspond to the two diastereomers of the 7-exo tautomer and the 7-endo tautomer. The X-ray powder analysis and the molecular structures of 7a-c clearly prove that these compounds, and probably 7d, are present in the solid state as a single diastereomer of the 7-exo tautomer which, on being dissolved, establishes an equilibrium with the other diastereomer through the 7-endo tautomer. This later had been proposed as a key intermediate in the cyclization of the 1,5-dinitrile system present in 7a-d but was not previously detected.