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Die 2-Amino-3-cyan-4,5-dihydrofurane 1a–c dimerisieren beim Erhitzen in Formamid zu den 2-(Furan-3-yliden)furo[2,3-d]pyrimidinen 3a–c; daneben findet eine neuartige Trimerisierung zu 4,4-Bis(furo[2,3-d]pyrimidin-2-yl)-2-butanolen 4b–e statt. Die Konstitution von 4d wird durch Rontgenstrukturanalyse ermittelt. Heterocyclic β-Enamino Esters, 40. About Dimerizates and Trimerizates of 2-Amino-3-cyano-4,5-dihydrofurans in Formamide. X-ray Analysis of a 4,4-Bis(furo[2,3-d]pyrimidin-2-yl)-2-butanol Upon heating in formamide the 2-amino-3-cyano-4,5-dihydrofurans 1a–c undergo dimerization reaction to 2-(furan-3-ylidene)furo[2,3-d]pyrimidines 3a–c; additionally, a novel trimerization reaction to the 4,4-bis(furo[2,3-d]pyrimidin-2-yl)-2-butanols 4b–e is observed. The structure of 4d is established by X-ray diffraction. |
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