The Dimroth Rearrangement: Synthesis and Interconversion of Isomeric Triazolothienopyrimidines
作者:Atef A. Hamed、El-Sayed H. El-Ashry、Ibrahim F. Zeid、Hesham F. Badr
DOI:10.3184/030823408x327875
日期:2008.6
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
三唑并噻吩并[3,2-e]嘧啶通过4-肼基-2-(甲硫基)噻吩并[2,3-d]嘧啶与甲酸、乙酸、溴化氰和二硫化碳的环化,并通过氧化发现衍生的醛腙是三唑并[4,3-c]异构体。这些 [4,3-c] 化合物在酸中抵抗异构化,但它们在碱性条件下会发生 Dimroth 重排为 [1,5-c] 异构体。一种这样的重排产物,5-甲氧基-8,9,10,11-四氢[1]苯并噻吩并[3,2-e][1,2,4]三唑并[1,5-c]嘧啶的晶体结构( X 射线分析证实了图 13b)。