二溴甲烷

• 产品号: A10456
• CAS号: 74-95-3
• 分子式: CH2Br2
• 分子量: 173.83458
• 纯 度: 99%, stab. with 50ppm BHT

产品别名

• 标题: Dibromomethane
• IUPAC标准名: dibromomethane
• IUPAC传统名: dibromomethane
• 别名: Methylene bromide

产品登记号

• Beilstein号: 969143
• MDL号: MFCD00000168
• CAS号: 74-95-3
• 默克索引号: 146061
• EC号: 200-824-2

产品性质

• 纯度: 99%, stab. with 50ppm BHT
• 沸点: 96-98°C
• 密度: 2.495
• 熔点: -53°C
• 折射率: 1.5410
• GHS危险声明: H332-H412
• 欧盟危险性物质标志: X
• GHS警示性声明: P261-P273-P271-P304+P340-P312-P501A
• 危险公开号: 20-52/53
• RTECS编号: PA7350000
• 安全公开号: 24-61
• TSCA收录: 是
• 联合国危险货物等级: 6.1
• 联合国危险货物编号: UN2664
• 联合国危险货物包装类别(PG): III

参考文献

• For in situ formation of dibromomethyllithium by reaction with lithiated 2,2,6,6-Tetramethylpiperidine, A18712, and use in a one-pot ester homologation sequence, safer and more convenient than the classical Arndt-Eistert (diazomethane) method, see: Org. Synth. Coll., 9, 426 (1998):
  
• Reaction with NaHMDS generates monobromocarbene, which reacts with alkenes to give bromocyclopropanes: Synthesis, 201 (1972). It can also be generated by reaction with diethylzinc in the presence of O₂: J. Chem. Soc., Chem. Commun., 364 (1975).
• The Simmons-Smith reaction (see Diiodomethane, A15457) may be extended to the use of dibromomethane in the cyclopropanation of simple electron-deficient alkenes, using a reducing agent prepared from NiBr₂, NaI and Zn: Bull. Chem. Soc. Jpn., 56, 1025 (1983); or with CuCl/Zn: J. Org. Chem., 55, 2491 (1990).
• With TiCl₄/Zn, methylenation of ketones occurs, as a useful mild alternative to the Wittig reaction: Tetrahedron Lett., 23, 4293 (1982); Org. Synth. Coll., 8, 386 (1993). For a variant using Zn, CuCl and catalytic TiCl₄, see: J. Org. Chem., 54, 2388 (1989).
• With alcohols, formaldehyde acetals can be formed under phase-transfer conditions: Bull. Chem. Soc. Jpn., 66, 2149 (1993). Diols give methylenedioxy derivatives, which are components of many biologically-important molecules. For use of KF in DMF as base in the methylenation of catechols, see: Tetrahedron Lett., 3361 (1976). KOH in DMSO has been recommended for the methylenation of base-stable carbohydrate diols: Synthesis, 421 (1982). For the methylenation of ribonucleosides under phase-transfer conditions, see: Synthesis, 715 (1981).