Dicarboxylic adds reactivity

The preferred unsaturation in the polyester backbone is the fumaric double bond, which results from using either fumaric acid or maleic anhydride as the unsaturated dicarboxylic add. Under the reaction conditions normally applied to synthesize the polyester, most of the maleic (ds) double bonds isomerize to fumaric (trans) double bonds. The unsaturated polyester macromolecule itself is either a very viscous liquid or a solid. Usually this polyester is dissolved in a reactive monomer containing a double bond capable of copolymerizing through a radical polymerization with the (fumaric) unsaturations in the polyester backbone. The workhorse of the readive solvents is styrene. The low-viscosity polyester solution (UP resin) thus obtained is formulated with a number of ingredients that provide critical properties, such as storage stability, reactivity, thixotropy, UV resistance, and color, before being sold by the polyester producer. 

In polar solvents the excited state of sufficiently electron deficient arenes will accept an electron from donors. The fates of the radical ion pairs produced include formation of products of addition to the arene ring. A new example of this mode of reactivity is the photochemical reaction of 1,4-dicyanonaphthalene with benzyl methyl ether in acetonitrile. This yields stereoisomers of the addition product (120). The reaction most likely involves electron transfer from the ether to the naphthalene excited state and subsequent ionisation of a proton from the benzyl ether radical cation. This produces a benzyl ether radical which adds to the naphthalene derivative. An analogous sequence is proposed to explain the photochemical formation of (121)-(124) from ultra-violet light irradiated solutions of naphthalene-1,2-dicarboxylic acid anhydride in methanolic benzene or acetonitrile containing isobutene, 2-butene or 2-methyl-2-butene. Here it is suggested that the alkene radical cation, formed by electron transfer to the excited state of the naphthalene, is attacked by methanol deprotonation... 

Unsubstituted pyridine, quinoline, and isoquinoline A-imines are the most reactive of all A-imines. They add to nitriles,1013 72-140 141 acetylene-dicarboxylic ester,75 139 142 propiolonitrile,143 propiolic esters,144 and carbon disfulfide.139 Dehydrogenation to a completely aromatic product, subsequent to the addition step, [see Eq. (15)] exerts an essential influence on the course of the reaction. 

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