Bromobimane

Bromobimane

Names
IUPAC names 3-(bromomethyl)-2,5,6-trimethyl-1H,7H- pyrazolo[1,2-a]pyrazole-1,7-dione
Other names Bromobimane, mBBr
Identifiers
CAS Number	71418-44-5
3D model (Jmol)	Interactive image
ChemSpider	102775
PubChem	114810
InChI InChI=1S/C10H11BrN2O2/c1-5-7(3)12-8(4-11)6(2)10(15)13(12)9(5)14/h4H2,1-3H3 Key: AHEWZZJEDQVLOP-UHFFFAOYSA-N 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
SMILES O=C1\C(=C(/N2/C(=C(\C(=O)N12)C)CBr)C)C
Properties
Chemical formula	C10H11BrN2O2
Molar mass	271.11 g·mol^−1
Melting point	152 to 154 °C (306 to 309 °F; 425 to 427 K)
Solubility in water	in MeOH, DMF, DMSO
Hazards
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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Infobox references

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 (λ_emission = 478 nm) to the thiol. Its alkylating properties are comparable to iodoacetamide.^[1]

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.

References

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.