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 (λemission = 478 nm) to the thiol. Its alkylating properties are comparable to iodoacetamide.[1]
Names | |
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Preferred IUPAC name 3-(Bromomethyl)-2,5,6-trimethyl-1H,7H-pyrazolo[1,2-a]pyrazole-1,7-dione | |
Other names Bromobimane, mBBr | |
Identifiers | |
3D model (JSmol) | |
ChemSpider | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C10H11BrN2O2 | |
Molar mass | 271.114 g·mol−1 |
Melting point | 152 to 154 °C (306 to 309 °F; 425 to 427 K) |
in MeOH, DMF, DMSO | |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards | alkylating agent |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Synthesis
Bromobimane is prepared from 3,4-dimethyl-2-pyrazolin-5-one (a condensation product of ethyl 2-methylacetoacetate with hydrazine) by chlorination followed by basic treatment; with aqueous K2CO3 under heterogeneous conditions, the required syn-bimane, 2,3,5,6-tetramethyl-1H,7H-pyrazolo[1,2-a]pyrazole-1,7-dione, is the major product. It can then be selectively brominated to the target bromobimane (with 1 equivalent of Br2; or dibromobimane, if 2 equivalents of Br2 are used):[2]
Bromobimanes are light-sensitive compounds and should be kept refrigerated and protected from light.