Original scientific paper

Base-Catalyzed Rearrangement of 2- Vinylpyrazolium Salts into 1,2- Dihydropyrimidines

Jose Elguero ; Instituto de Quimica Medica, C.S.I.C., Juan de la ,Cierva 3, 28006 Madrid, Spain
Antonio de la Hoz ; Departamento de Quimica Organica, Facultad de Quimica, Universidad Complutense, 28040 Madrid, Spain
Carmen Pardo ; Departamento de Quimica Organica, Facultad de Quimica, Universidad Complutense, 28040 Madrid, Spain

Abstract

The ring transformation of 2-viny1pyrazolium salts into dihydropyrimidines is the last step of a process which starts from
neutra1 pyrazoles. Globally,it results in the insertion of a :'CE-
-CHOH-E (E = C02Me) fragment between the two nitrogen atoms of a l-substituted pyrazole. The dihydropyrimidines formed were identified spectroscopically (iH and i3C NMR) and the relative configuration of the two chiral centres established by the X-ray structure analysis of a picrate. Finally, a plausible mechanism for the formation and epimerization of dihydropyrimidines is proposed.

Keywords

Hrčak ID:

177584

URI

https://hrcak.srce.hr/177584

Publication date:

16.5.1986.

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