4-methyl-3-(pent-4-enyl)benzothiazolium bromide | 134486-74-1

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 苯并噻唑类
• 英文名称: 4-methyl-3-(pent-4-enyl)benzothiazolium bromide
• 英文别名: 3-pent-4-enyl-1,3-benzothiazol-3-ium;bromide
• CAS: 134486-74-1
• 化学式: Br*C₁₂H₁₄NS
• 分子量: 284.22
• InChiKey: XIOLZNJBPFOATR-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  0.16
• 重原子数：
  15
• 可旋转键数：
  4
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  32.1
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  苯并噻唑 、 5-溴-1-戊烯 以 正丁醇 为溶剂， 反应 3.0h， 以63.2%的产率得到4-methyl-3-(pent-4-enyl)benzothiazolium bromide
  参考文献：
  名称：

  Reactivity of the thiazolium C2 ylide in aprotic solvents: novel experimental evidence for addition rather than insertion reactivity

  摘要：

  Two thiazolium compounds were synthesized specifically labeled at their C2 positions: 3,4,5-trimethyl[2-C-13]thiazolium nitrate and 3-benzyl-5-(beta-ethoxyethyl)-4-methyl[2-C-13]thiazolium bromide, with a view to examine their pathways leading to dimerization in strongly basic medium using C-13 NMR. On addition of less than 1 equiv of base the N-methyl ion first formed an unsymmetrical dimer in which the C2 atoms of two molecules were bonded to each other and only one of them still carried a hydrogen; that unsymmetrical dimer upon addition of excess base lost the remaining hydrogen at C2 and was converted to a mixture of syn and anti symmetrical dimers in nearly equal amounts. The sequence of observations on addition of base to the N-methyl derivative is consistent with nucleophilic addition of the conjugate base to a second thiazolium ion at its C2 position. Since the unsymmetrical dimer is formed first, rather than the symmetrical dimer, the latter cannot result from direct dimerization of two conjugate bases (ylides) by a carbene mechanism. Instead, a carbanion-addition mechanism was further supported by two experiments. A ''crossover'' experiment was designed in which unsymmetrical dimers were detected in Me2SO on addition of limiting potassium tert-butoxide to thiazolium ions containing [2-C-13]-H and [2-C-12]-D, under conditions such that there was little H/D exchange observed at the C2 position. Also, N-3-alkenylthiazolium ions were synthesized, that, if carbenic reactivity had existed, would have resulted in formation of cyclopropanes. In preference to the intramolecular reaction, intermolecular unsymmetrical dimers resulted in each case, consistent with nucleophilic addition. On addition of base to the N-benzylthiazolium ion, the first product to be detected by C-13 NMR was the syn/anti symmetrical dimer mixture (again bonded via the C2 atoms), that underwent a [1,3]-sigmatropic rearrangement of one of the benzyl groups from N3 to C2. According to H-1 NMR recorded within minutes of mixing, the unsymmetrical dimer precedes the symmetrical one for this salt as well. The reactivity of the C2 ylide derived from the N-methyl and N-benzylthiazolium ions can be rationalized according to an ionic addition reaction, implying that the related thiamin (vitamin B1) conjugate base (ylide) behaves similarly.

  DOI：

  10.1021/jo00017a010