3,4-dibromo-5-(methylthio)pyrazole | 923036-06-0

• 分子结构分类: 有机化合物 - 有机硫化合物 - 硫醚类
• 英文名称: 3,4-dibromo-5-(methylthio)pyrazole
• 英文别名: 4,5-Dibromo-3-(methylsulfanyl)-1H-pyrazole；4,5-dibromo-3-methylsulfanyl-1H-pyrazole
• CAS: 923036-06-0
• 化学式: C₄H₄Br₂N₂S
• 分子量: 271.963
• InChiKey: HIMSORGWRWVEHR-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.8
• 重原子数：
  9
• 可旋转键数：
  1
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  54
• 氢给体数：
  1
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  3,4-dibromo-5-methylthio-1-vinylpyrazole 在 potassium permanganate 作用下， 以 水 、 丙酮 为溶剂， 反应 5.0h， 以86%的产率得到3,4-dibromo-5-(methylthio)pyrazole
  参考文献：
  名称：

  The N-vinyl group as a protection group of the preparation of 3(5)-substituted pyrazoles via bromine–lithium exchange

  摘要：

  Treatment of 3,4,5-tribromopyrazole with 1,2-dibromoethane and triethylamine gave 3,4,5-tribromo-1-vinylpyrazole, which underwent regioselective bromine-lithium exchange at the 5-position. Subsequent addition of an electrophile gave 5-substituted 3,4-dibromo-1-vinylpyrazoles. These underwent bromine-lithium or bromine-magnesium exchange predominantly at the 4-position, with the regioselectivity between the 3- and 4-positions being influenced by the nature of the metal and the 5-substituent. The 5-substituted products were de-vinylated by mild treatment with KMnO4 affording 3-substituted pyrazoles. Alternatively, the 1-vinyl group could be used in ring-closing metathesis. Thus, 5-allylthio-1-vinylpyrazole produced 5H-pyrazolo[5,1-b] [1,3]thiazine upon treatment with Grubbs' second-generation catalyst. (c) 2006 Elsevier Ltd. All rights reserved.

  DOI：

  10.1016/j.tet.2006.10.009

文献信息

• The N-vinyl group as a protection group of the preparation of 3(5)-substituted pyrazoles via bromine–lithium exchange
  作者：Brian Iddon、Janne Ejrnæs Tønder、Masood Hosseini、Mikael Begtrup

  DOI：10.1016/j.tet.2006.10.009

  日期：2007.1

  Treatment of 3,4,5-tribromopyrazole with 1,2-dibromoethane and triethylamine gave 3,4,5-tribromo-1-vinylpyrazole, which underwent regioselective bromine-lithium exchange at the 5-position. Subsequent addition of an electrophile gave 5-substituted 3,4-dibromo-1-vinylpyrazoles. These underwent bromine-lithium or bromine-magnesium exchange predominantly at the 4-position, with the regioselectivity between the 3- and 4-positions being influenced by the nature of the metal and the 5-substituent. The 5-substituted products were de-vinylated by mild treatment with KMnO4 affording 3-substituted pyrazoles. Alternatively, the 1-vinyl group could be used in ring-closing metathesis. Thus, 5-allylthio-1-vinylpyrazole produced 5H-pyrazolo[5,1-b] [1,3]thiazine upon treatment with Grubbs' second-generation catalyst. (c) 2006 Elsevier Ltd. All rights reserved.