The Dimroth rearrangement: synthesis and interconversion of isomeric triazolothienopyrimidines

AA Hamed, ESH El-Ashry, IF Zeid…

Index: Hamed, Atef A.; El-Ashry, El-Sayed H.; Zeid, Ibrahim F.; Badr, Hesham F. Journal of Chemical Research, 2008 , # 6 p. 334 - 339

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Citation Number: 2

Abstract

Triazolo-thieno [3, 2-e] pyrimidines obtained by cyclisation of 4-hydrazino-2-(methylthio) thieno [2, 3-d] pyrimidine with formic acid, acetic acid, cyanogen bromide and carbon disulfide, and by oxidation of the derived aldehyde hydrazones, are found to be the triazolo [4, 3-c] isomers. These [4, 3-c] compounds resist isomerisation in acid, but they undergo Dimroth rearrangement to the [1, 5-c] isomers under basic conditions. The crystal structure ...