Maleimidobenzoic acid

The maleimide is prebuilt into the molecule in a separate step. Maleimidobenzoic acid [17075-07-7] or its acid haUde was used to synthesize maleintide-terrninated polyamides (16,17) or polyesters (27) from amino- or hydroxy-terminated polyamides and polyesters, respectively. The Hterature on bismaleimide prepolymers and bismaleimide building blocks is quite extensive (28), but only a limited number of BMI building blocks have been used for commercial resin formulations. 

An interesting approach to maleimide-terminated phenoxy resin has recently has described (42). para-Maleimidobenzoic acid was reacted with diglyci-dylbisphenol-A epoxy resin in the presence of catalyst to provide the bismale-imide of Fig. 13. Instead of diglycidyl bisphenol-A, linear epoxy resin pre-polymers can be used in this reaction to form a maleimide terminated phenoxy resin. Another suitable functionalized monomaleimide is m- or p- N-(hydroxyphenyl) maleimide which is synthesized from maleic anhydride and m-aminophenol in DMF as a solvent at 70 °C. The purified hydroxyphenyl maleimide was reacted with epoxy resin to form novel BMIs as outlined in Fig. 14. The new BMI and phenoxy oligomers polymerize at temperatures of 200-220 °C, but the cure temperatures can be significantly lowered when catalysts such as imidazoles or triphenylphosphine are added. The cured homopolymers show Tg of 140 and 230 °C for the n = 2 and the n = 1 polymer, respectively(43). 

Fig, 13. Maleimide-terminated phenoxy resin obtained from 4-maleimidobenzoic acid (42)... 

Reaction of the enzyme with either 5,5 -dithio-bis(2-nitrobenzoic acid) or 3-maleimidobenzoic acid and coupling of the products with the thiol groups of erythrocytes... 

The coupling of a-amylase treated with either 5,5 -dithio-bis(2-nitrobenzoic acid) or 3-maleimidobenzoic acid with the surface thiol groups of human erythrocytes could be blocked with 1,4-dithiothreitol. a-Amylase and glucoamylase immobilized by incorporation into polyacrylates generated in situ retained then-enzymic activity, even when polymerization was induced by irradiation of the monomer. ... 

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