C−H Activation with Elemental Sulfur: Synthesis of Cyclic Thioureas from Formaldehyde Aminals and S8
作者:Michael K. Denk、Shilpi Gupta、John Brownie、Sabiha Tajammul、Alan J. Lough
DOI:10.1002/1521-3765(20011015)7:20<4477::aid-chem4477>3.0.co;2-i
日期:2001.10.15
The C-H activation of cyclic formaldehyde aminals LCH2 (L = RN-CH2CH2CH2-NR and RNCH2CH2-NR, R = Me, Et, iPr, tBu, or Ph) with S8 proceeds at unusually low temperatures (T< 160 degrees C) and results in the formation of the respective thioureas LC=S and H2S. The reaction constitutes a new, solvent-free method for the synthesis of thioureas that eliminates the toxic and highly flammable CS2. For R =
环状甲醛缩醛LCH2(L = RN-CH2CH2CH2-NR和RNCH2CH2-NR,R = Me,Et,iPr,tBu或Ph)的CH活化在异常低的温度(T <160摄氏度)下进行在各自的硫脲的形成中,LC = S和H 2S。该反应构成了一种新的无溶剂合成硫脲的方法,该方法消除了有毒且高度易燃的CS2。对于R = tBu,离子型硫氰酸卡宾[LCH] + SCN-占据了产物谱,并且以低收率获得了相应的硫脲。研究了类似的硫和氧环系统对S8的反应性。1,3-二硫杂环戊烷可干净地转化为1,3-二硫杂环戊-2-硫酮(S8,14 d,190摄氏度),在这方面类似于环状甲醛缩醛。1,3-二氧戊环(L = OCH2CH2O)即使在强力反应条件下(190摄氏度,14天)也对硫完全惰性。在理论上的CBS-4和B3LYP / 6-31G(d)水平上研究了由缩醛胺形成的硫脲的形成。