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]

Bromobimane
Names
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
UNII
  • InChI=1S/C10H11BrN2O2/c1-5-7(3)12-8(4-11)6(2)10(15)13(12)9(5)14/h4H2,1-3H3 checkY
    Key: AHEWZZJEDQVLOP-UHFFFAOYSA-N checkY
  • InChI=1/C10H11BrN2O2/c1-5-7(3)12-8(4-11)6(2)10(15)13(12)9(5)14/h4H2,1-3H3
    Key: AHEWZZJEDQVLOP-UHFFFAOYAR
  • O=C1\C(=C(/N2/C(=C(\C(=O)N12)C)CBr)C)C
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).
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Synthesis

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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]

 
Bromobimane synthesis

Bromobimanes are light-sensitive compounds and should be kept refrigerated and protected from light.

References

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  1. ^ Paul C. Chinn; Vincent Pigiet & Robert C. Fahey (1986). "Determination of thiol proteins using monobromobimane labeling and high-performance liquid chromatographic analysis: Application to Escherichia coli thioredoxin". Analytical Biochemistry. 159 (1): 143–149. doi:10.1016/0003-2697(86)90319-2. PMID 3544950.
  2. ^ Kosower, Edward M.; Pazhenchevsky, Barak (1980). "Bimanes. 5. Synthesis and Properties of syn- and anti-1,5-Diazabicyclo[3.3.0]octadienediones (9,10-Dioxabimanes)". Journal of the American Chemical Society. 102 (15): 4983–4993. doi:10.1021/ja00535a028.