Fumarate Half-Esters

Maleic anhydride reacts with alcohols to give alkyl hydrogen maleates (see Chapter 3). Isomerization gives alkyl hydrogen fumarates. These 

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The rate at which Cr+2 reacts with a variety of half-ester complexes of fumaric acid is not very different from the rate at which it reacts with the fumaric complex. Thus, the specific rates for the methylfumarate (20), phenylfumarate (9), and fumaric acid (20) complexes are 1.4, 1.5, and 1.3 respectively. However, when... 

Copolymerization with Vinyl Carboxylic Acids. The acids usually suggested for this method include maleic and fumaric acids and their half esters, crotonic, itaconic, methacrylic, and acrylic acid. The latter three appear to be most generally preferred. On occasion, the amides of these acids are suggested for achieving the same end result (24). Suggested specifically for butadiene-styrene latexes are these acids at about 0.05-10 wt. % based on total monomer. The latex should be adjusted to pH 8-11 (28, 29). For copolymerization with vinyl acetate (2) and acrylic monomers (18) identical acid monomers are suggested. Use of such latexes is claimed to give F/T stable emulsion floor polishes (25) and paints (16). 

Stearyl fumarate is a half ester of fumaric acid with stearyl alcohol (octadeca-nol). Although stearyl fumarate might be expected to have dough-strengthening properties similar to those of SSL, this was not found to be so in practice, and the product was not a commercial success. Stearyl fumarate is still approved by the FDA for use in bread. 

Condensation reactions between hydroxyethyl cellulose or carboxy methyl hydroxy-ethyl cellulose provides potentially useful textile sizing resins.Starch materials have been treated with MA to obtain starch with maleate half-ester residues, with a substitution degree of 0.01-3.00. Styrene monomer is grafted onto the maleate/fumarate residues, with high efficiency, using standard free-radical initiators. 

The preceding schemes for preparing estrone have the disadvantage that they yield the steroid as a mixture of the two enantiomers. Preparing material identical with that which occurs in Nature requires resolution of those diastereomers. This also implies loss of half of the mass of final product. A synthesis that produces estrone and its derivatives directly without the need for that extra step depends on the use of chiral auxiliaries in the formation of ring C. The crucial step in this synthesis involves Diels-Alder condensation of the diene 16-1 with the fumaric ester aldehyde 16-2 in the presence of the oxazaborolidinium salt shown in Figure 3.1 this reaction affords the tricyclic intermediate 16-3 as a single enantiomer (Scheme 3.16). 

Elving and co-workers [39, 40] investigated the polarographic behavior of mono- anddibromosubstituted maleic andfumaric acids and their esters. Monobromomaleic acid is reduced to maleic, fumaric, and butadiene-1,2,3,4-tetracarboxylic acid, where the proportions of the products depend on the pH value. Monobromofumaric acid is reduced to fumaric acid. The esters of both acids are reduced to the esters of unsubstituted fumaric acid. Dibromomaleic and dibromofumaric acids and their esters are reduced to acetylene-dicarboxylic acid, and the half-wave potentials of the cis acid and its diethyl ester are less negative (by 0.04-0.18 and 0.10-0.12 V, respectively, depending on the pH value) than the half-wave potentials of the trans compounds. 

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