Bromobimane
Bromobimane or monobromobimane is a heterocyclic compound and bimane dye that is used as a reagent in biochemistry. While bromobimane itself is essentially nonfluorescent, it alkylates thiol groups, displacing the bromine and adding the fluorescent tag to the thiol. Its alkylating properties are comparable to iodoacetamide.Synthesis
Bromobimane is prepared from 3,4-dimethyl-2-pyrazolin-5-one by chlorination followed by basic treatment; with aqueous K2CO3 under heterogeneous conditions, the required syn-bimane, 2,3,5,6-tetramethyl-1H,7H-pyrazolopyrazole-1,7-dione, is the major product. It can then be selectively brominated to the target bromobimane :
Bromobimanes are light-sensitive compounds and should be kept refrigerated and protected from light.
