General Description
BMOE, BMB and BMH are homobifunctional, maleimide crosslinkers for conjugation between sulfhydryl groups (-SH). Such bismaleimide crosslinkers are commonly used to explore and characterize protein structure (i.e., oligomerization) or protein interactions. Because BMOE, BMB and BMH have the same reactivity but differ in length, the relative success of these three reagents in forming crosslinks between sites in a protein oligomer or interaction can assist in determining intra- and intermolecular distances.
Synthesis
1,2-Bis(maleimido)ethane was prepared from ethylenediamine and maleic anhydride using acetic anhydride as the dehydrating agent with nickel acetate and triethylamine as catalysts. To a 1-L three-necked flask fitted with a paddle stirrer, reflux condenser, and nitrogen inlet were added 300 mL of freshly distilled N, N-dimethyl formamide, 0.5 mol (49.0 g) of maleic anhydride, and 0.25 mol (98.1 g) of ethylenediamine. The temperature of the solution rose to 115°C and its opaque color changed to yellow. Stirring was after that continued for 30 minutes at 90°C. Then 0.5 g of nickel(II) acetate, 25 mL of triethylamine, and 118 mL of acetic anhydride were added to the reaction vessel while maintaining the system at 90°C for another 30 min. The reaction mixture was cooled to 30°C, poured into 2 L of ice water, and stirred for 10 min to crystallize the BMI. The resulting brown precipitate was filtered off by suction, washed twice with 1 L of water, and filtered. For further purification, the product was dissolved in 300 mL of dry acetone, refluxed with 15 g of charcoal, and filtered. The volume of the solution was reduced to 100 mL by evaporation and then kept at 0°C overnight. The resulting precipitate was filtered off by suction and dried[1].
References
[1] A. Ashok Kumar, M. Alagar, K. Dinakaran. “Preparation and characterization of siliconized epoxy-1,2-bis(maleimido)ethane intercrosslinked matrix materials.” Journal of Applied Polymer Science 89 14 (2003): 3808–3817.
