Reaction with maleic acid

Initialiy, 4-bromobenzyl-cyanide is reacted with sodium amide and 2-chloropyridine to give bromophenyl-pyridyl acetonitrile. This is then reacted with sodium amide then dimethyi amino ethyl chloride to give 4.bromophenyl-dimethylamlnoethyl-pyrldyi acetonitrlie. This intermediate is then hydrolyzed and decarboxylated to bromphenirame using 80% H2SO4 at 140°-150°C for 24 hours. The brompheniramine maieate may be made by reaction with maleic acid in ethanol followed by recrystallization from pentanoi. 

According to U.S. Patent 2,676,964 to 1.0 mol of potassium amide in 3 liters of liquid ammonia, is added 1.0 mol of 2-benzylpyridine. After 15 minutes, 1.1 mols of 3reaction product decomposed with water and ether extracted. The ether layer is dried over Sodium sulfate and after evaporation the residue is distilled, giving the 3-phenyl-3-(2-pyridyl)-N,N-dimethylpropylamine, BP 139°-142°C/1-2 mm. The maleate is produced by reaction with maleic acid. 

Padwa and Prein (105,106) applied chiral, but racemic, isomiinchnone dipoles in diastereoselective 1,3-dipolar cycloadditions. The carbonyl ylide related isomiinch-none derivative rac-70 was obtained from the rhodium-catalyzed cyclization of diazo-derivative rac-69 (Scheme 12.24) (105). The reactions of the in situ formed dipole with a series of alkenes was described and in particular the reaction with maleic acid derivatives 71a-c gave rise to reaction with high selectivities. The tetracyclic products 72a-c were all obtained in good yield with high endo/ exo and diastereofacial selectivities. In another paper by the same authors, the reactions of racemic isomilnchnones having an exo-cyclic chirality was described (106). 

Bergemann K, Fanghanel F, Knackfuss B, Liithge T, Schukat G. (2004) Modification of carbon black properties by reaction with maleic acid derivatives. Carbon 42 2338-2340. 

The reactivity of 4,6-benzo[/ ][l,7]naphthyridine in Diels-Alder reactions with maleic acid and dimethyl acetylenedicarboxylate was examined. The reaction afforded adduct 332 (1996MI5). 6-Ethoxycarbonyl- 333a and phenacylmethylides 333b were used as 1,3-dipolar reagents in reactions with methacrylic acid, methyl methacrylate, butyl vinyl ether, methyl vinyl ketone, maleic anhydride and dimethyl acetylenedicarboxylate (1996MI5, 1999AJC149). 

A wide range of chemical agents, catalysts and conditions for the glycolysis of unsaturated polyester resins, used in the manufacture of buttons, have been described in a recent patent.34 In addition to different metal acetates, the following compounds have been proposed to be catalytically active in PET glycolysis sodium methylate, sodium ethylate, sodium hydroxide, methane-sulfonic acid, magnesium oxide, barium oxide and calcium oxide. Different applications of the depolymerization products were described, e.g., preparation of fresh unsaturated polyesters by reaction with maleic acid, maleic acid/ phthalic anhydride or maleic anhydride/terephthalic acid or the synthesis of polyurethane resins by reaction with a diisocyanate. 

The Diels-Alder reaction with maleic acid esters can be easily performed [25]. However, when it is carried out at high temperature ( 250°C), partial decarboxylation takes place, with formation of ketone-type dirnCTS [26], yielding polyfunctional derivatives (Fig. 4.9) that could be good monomeric units for polymer synthesis [27]. 

N-Maleyl derivatives of proteins are obtained at alkaline pH by reaction with maleic acid anhydride. The acylated product is cleaved at pH < 5, regenerating the protein ... 

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