Under conditions normally applied to transform thioureas into the corresponding carbodiimides, cis- and trans-1-(2-aryl-1,3-dithian-5-yl)-2-thioureas 7 and 8 undergo a rearrangement to 5-aryl-3-imino-7,7a-dihydro-1H, 3H, 5H-thiazolo[3,4-c]thiazoles 9/10 with cis- and trans-fused rings, respectively. The structures of these novel heterocycles were established by X-ray analysis of compounds 9a, 9d, and
在通常用于将
硫脲转化成相应的碳二
亚胺的条件下,顺式和反式-1-(2-芳基-1,3-二
硫基-5-基)-2-
硫脲7和8进行重排成5-芳基-3 -亚
氨基-7,7a-二氢-1 H,3 H,5 H-
噻唑并[3,4- c ]
噻唑9/10,分别具有顺式和反式稠环。这些新型杂环的结构是通过对化合物9a,9d和10d进行X射线分析确定的。该顺式-融合化合物9是热力学上更稳定的。重排的立体
化学结果取决于芳基部分的碳鎓离子稳定能力和所用试剂系统。在Ar = Ph,p -Cl-Ph,p - O 2 N-Ph的情况下,可以指导反应主要递送顺式-
噻唑并
噻唑9或反式-
噻唑并
噻唑10。当Ar = 5-甲基-4-
咪唑基或p -Me 2 N-Ph时,形成顺-
噻唑并
噻唑(9a和9b,分别)是独立于反应条件的强烈拥护者,与此相反,2-芳基类似物可以将(1,3-dithian-5-yl)-2-thiourea 7g转化为碳二
亚胺1