Reinvestigating the Reaction of 1<i>H</i>-Pyrazol-5-amines with 4,5-Dichloro-1,2,3-dithiazolium Chloride: A Route to Pyrazolo[3,4-<i>c</i>]isothiazoles and Pyrazolo[3,4-<i>d</i>]thiazoles
作者:Maria Koyioni、Maria Manoli、Manos J. Manolis、Panayiotis A. Koutentis
DOI:10.1021/jo500509e
日期:2014.5.2
formation of pyrazolo[3,4-c]isothiazoles 5. Furthermore, thermolysis of N-(4-chloro-5H-1,2,3-dithiazol-5-ylidene)-1H-pyrazol-5-amines 3 gives 1H-pyrazolo[3,4-d]thiazole-5-carbonitriles 4. Single crystal X-ray crystallography supports the structure of 4,6-dimethyl-6H-pyrazolo[3,4-c]isothiazole-3-carbonitrile (5a) and helps resolve a previous incorrect structural assignment of 1H-pyrazolo[3,4-d]thiazole-5-carbonitriles
Appel盐1与1 H-吡唑-5-胺2的反应生成主要产物N-(4-氯-5 H -1,2,3-二噻唑-5-亚烷基)-1 H-吡唑-5-胺3和6 H-吡唑并[3,4- c ]异噻唑-3-腈5以及几种次要副产物。当吡唑被N-1甲基化时,可以通过调节反应介质的pH来改变3:5的产物比例:酸性条件有利于二噻唑基3的形成,而碱性条件有利于吡唑并[3,4- c]异噻唑5。此外,对N-(4-氯-5 H -1,2,3-二噻唑-5-亚烷基)-1 H-吡唑-5-胺3进行热解得到1 H-吡唑并[3,4- d ]噻唑- 5-腈4。单晶X射线晶体学支持4,6-二甲基-6 H-吡唑并[3,4- c ]异噻唑-3-甲腈(5a)的结构,并有助于解决先前错误的1 H-吡唑并[3]的结构分配。,4 - d ]噻唑-5-腈4。