Synthesis of new 1,2,4-oxadiazolidin-5-ylthiophenes and thienopyrimidine derivatives by aza-Wittig reaction using a thienyl carbodiimide

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• 作者：Afaf M. Abdel Hameed ^{afafabdelhamid1@yahoo.com}
• 关键词：Carbodiimide ; Cycloaddition ; 1 ; 2 ; 4-Oxadiazolidin-5-ylideneaminothiophene derivatives ; Thienopyrimidine ; Aza-Wittig reaction
• 刊名：Chinese Chemical Letters
• 出版年：2012
• 出版时间：April, 2012
• 年：2012
• 卷：23
• 期：4
• 页码：411-414
• 全文大小：268 K

文摘

Azidation of aminothiophene derivative 1 afforded the corresponding azido derivative 2. The latter reacted with triphenylphosphine to afford iminophosphorane derivatives 3. Reacting 3 with phenylisocyanate gave the highly reactive carbodiimide intermediate 4, which was reacted with different nitrones to afford new 1,2,4-oxadiazolidin-5-ylidene-aminothiophenes 5a-c. Treatment of 4 with absolute EtOH at room temperature gave methyleneamino-5-(methylthio)thiophene 7, (methylthio)-3-(3-phenylureidothiophene)-2-carboxylate 8 or thienopyrimidine 9 and 10 at refluxing temperature. Finally reaction of carbodiimide intermediate 4 with different secondary amines gave the new thienopyrimidines 11a-c.