Maleimides 2 molecules

Maleimides Alkyl and aryl maleimides in small concentrations, e.g., 5-10 wt% significantly enhance yield of cross-link for y-irradiated (in vacuo) NR, cw-l,4-polyisoprene, poly(styrene-co-butadiene) rubber, and polychloroprene rubber. A-phenyhnaleimide and m-phenylene dimaleimide have been found to be most effective. The solubihty of the maleimides in the polymer matrix, reactivity of the double bond and the influence of substituent groups also affect the cross-fink promoting ability of these promoters [82]. The mechanism for the cross-link promotion of maleimides is considered to be the copolymerization of the rubber via its unsaturations with the maleimide molecules initiated by radicals and, in particular, by allyfic radicals produced during the radiolysis of the elastomer. Maleimides have also been found to increase the rate of cross-linking in saturated polymers like PE and poly vinylacetate [33]. 

The mechanism of the cross-link promotion of maleimides is assumed to be based on copolymerization of the polymer via its unsaturations with the maleimide molecules initiated by radicals, and in particular, by allylic radicals produced during the radiolysis of the polymer. ... 

Tetraoxospiro[pyrrolidin-l,2 -(pyrrolidino[l,3,4-c]pyrrolidines)] from azomethines and 2 maleimide molecules... 

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 affinity label is a molecule that contains a functionality that is chemically reactive and will therefore form a covalent bond with other molecules containing a complementary functionality. Generally, affinity labels contain electrophilic functionalities that form covalent bonds with protein nucleophiles, leading to protein alkylation or protein acylation. In some cases affinity labels interact selectively with specific amino acid side chains, and this feature of the molecule can make them useful reagents for defining the importance of certain amino acid types in enzyme function. For example, iodoacetate and A-ethyl maleimide are two compounds that selectively modify the sulfur atom of cysteine side chains. These compounds can therefore be used to test the functional importance of cysteine residues for an enzyme s activity. This topic is covered in more detail below in Section 8.4. 

Figure 1.88 The maleimide group of BMPA reacts with a thiol-containing molecule to result in a modification having a terminal carboxylate group. Amine-containing molecules then can be conjugated to the carboxylate using a carbodiimide reaction with EDC.

Figure 4.18 BMH contains two maleimide groups specific for crosslinking sulfhydryl-containing molecules. The thioether bonds that are formed are stable.

Figure 5.4 SMCC reacts with amine-containing molecules to form stable amide bonds. Its maleimide end then may be conjugated to a sulfhydryl-containing compound to create a thioether linkage.

Figure 5.8 The reaction of GMBS with an amine-containing molecule yields a maleimide-activated intermediate that then can be used to crosslink with a sulfhydryl-containing compound.

Figure 5.12 MPBH reacts with sulfhydryl-containing molecules through its maleimide end to produce thioether linkages. Its hydrazide group then can be used to conjugate with carbonyl-containing molecules (such as periodate-oxidized carbohydrates that contain aldehydes) to give hydrazone bonds.

Figure 5.34 Benzophenone-4-maleimide can couple to thiol-containing molecules to form stable thioether bonds. Exposure of the benzophenone group to UV light causes transition to a triplet-state ketone of high reactivity for insertion into C—H or N—H bonds.

Figure 9.47 A maleimide-containing cyanine dye can be used to label thiol-containing molecules to form thioether bonds.

---