5-(tert-butyldiphenylsilyl)-1-hydroxy-4-(methylthio)pyrazole

• 分子结构分类: 有机化合物 - 有机硫化合物 - 硫醚类
• 英文名称: 5-(tert-butyldiphenylsilyl)-1-hydroxy-4-(methylthio)pyrazole
• 英文别名: Tert-butyl-(2-hydroxy-4-methylsulfanylpyrazol-3-yl)-diphenylsilane
• 化学式: C₂₀H₂₄N₂OSSi
• 分子量: 368.575
• InChiKey: OUBLPVIDRHZKGL-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.11
• 重原子数：
  25
• 可旋转键数：
  5
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  63.4
• 氢给体数：
  1
• 氢受体数：
  3

反应信息

• 作为产物：
  描述：

  叔丁基二苯基氯硅烷 在 N,N-二异丙基乙胺 、 lithium diisopropyl amide 作用下， 以 四氢呋喃 、 二氯甲烷 为溶剂， 反应 12.74h， 生成 5-(tert-butyldiphenylsilyl)-1-hydroxy-4-(methylthio)pyrazole
  参考文献：
  名称：

  Regioselective Introduction of Electrophiles in the 4-Position of 1-Hydroxypyrazole via Bromine−Lithium Exchange

  摘要：

  Two protocols for introduction of electrophiles at the 4-position of 1-hydroxypyrazoles have been developed. The first is deprotonation of 4-bromo-1-[(tert-butyldiphenylsilyl)oxy]pyrazole (6) with LDA to produce the 5-lithio derivative in which the silyl group migrates spontaneously from oxygen to C-5 affording 4-bromo-5-(tert-butyldiphenylsilyl)-1-lithoxypyrazole (8). Subsequent treatment with t-BuLi causes bromine-lithium exchange to give 5-tert-butyldiphenylsilyl-4-lithio-1-lithoxypyrazole which is trapped with electrophiles affording 4-substituted 5-(tert-butyldiphenylsilyl)-1-hydroxypyrazoles 9a-e in a one-pot sequence. The second is treatment of 4-bromo-1-hydroxypyrazole (5) with excess LDA and trimethylsilyl chloride to produce 3,5-bis(trimethylsilyl)-4-bromo-1-hydropyrazole (12), which upon sequential metalation with n-BuLi and reaction with electrophiles affords 4-substituted 3,5-bis(trimethylsilyl)-1-hydroxypyrazol 13a-e. The tert-butyldiphenylsilyl group of 9a and the trimethylsilyl groups of 12 can be removed selectively by treatment with tetrabutylammonium fluoride in THF in the presence of trifluoroacetic acid.

  DOI：

  10.1021/jo981970w