Uses
3,4,5-Tribromopyrazole is used in the preparation of 1-aryl-4-substituted piperazine CCR1 antagonists for the treatment of inflammation and immune disorders.
Synthesis
Step A: 1H-pyrazole (6.95 g, 0.1 mol) and sodium hydroxide (16 g, 0.4 mol) were dissolved in 400 mL of water, and bromine (48 g, 0.3 mol) was added slowly and dropwise with stirring over 1 hour. The reaction mixture was continued to be stirred for 1 h. The reaction mixture was filtered and the filter cake was washed with deionized water and dried to give 3,4,5-tribromo-1H-pyrazole (25.2 g, 81% yield). Mass spectral analysis showed m/z 302.9 [M + H]+.
References
[1] Journal of the Chemical Society, Dalton Transactions, 2002, # 11, p. 2297 - 2301
[2] Journal of Medicinal Chemistry, 2016, vol. 59, # 13, p. 6070 - 6085
[3] Patent: US9617268, 2017, B2. Location in patent: Page/Page column 414; 415
[4] Journal of Organic Chemistry, 1986, vol. 51, # 24, p. 4656 - 4660
[5] Tetrahedron, 2007, vol. 63, # 1, p. 56 - 61
