Efficient synthesis of tri- and difluoroacetyl hydrazides as useful building blocks for non-symmetrically substituted, fluoroalkylated 1,3,4-oxadiazoles
作者:Grzegorz Mlostoń、Emilia Obijalska、Alicja Żurawik、Heinz Heimgartner
DOI:10.1007/s10593-016-1845-3
日期:2016.2
A convenient and efficient approach to 2-arylamino-5-fluoroalkyl-1,3,4-oxadiazoles has been established via heterocyclization of tri- and difluoroacetylated thiosemicarbazides using dicyclohexylcarbodiimide. A heterocyclization performed with selected thiosemicarbazides under basic conditions led to 4-aryl-5-fluoroalkyl-2,4-dihydro-3H-1,2,4-triazole-3-thiones in moderate yields. The starting fluoroacetylated
通过使用二环己基碳二亚胺使三氟和二氟乙酰化的硫代氨基脲进行杂环化, 已经建立了一种方便有效的2-芳基氨基-5-氟烷基-1,3,4-恶二唑的方法。在碱性条件下用选定的硫代氨基脲进行的杂环化反应以中等收率得到了4-芳基-5-氟烷基-2,4-二氢-3 H -1,2,4-三唑-3-硫酮。通过用相应的酸酐对苄氧羰基保护的肼进行氟乙酰化,然后进行氢解脱保护并与芳基异硫氰酸酯反应,来制备起始的氟乙酰化的硫代氨基脲。氟乙酰化的氨基脲的制备方法相似,但所有实现其杂环化的尝试均未成功。