Dimethylmalic acid anhydride

Deacylation of derivatives formed by acid anhydrides (maleic, citra-conic, and 2,3-dimethylmaleic) containing double bonds (cis) occurs at a much faster rate under mild conditions. Several mechanisms have been proposed for deacylating these derivatives formed from the double bond containing anhydrides (9,46,47,48,49). The most important structural factor in the deacylation process is the cis double bond which maintains the terminal carboxyl group in the spatial orientation that makes a nucleophilic attack on the amide carbon much more probable. 

At least eight acid anhydrides have been found in cigarette smoke, including maleic anhydride and succinic anhydride and their alkylated derivatives [Schumacher et al. (3553), Newell et al. (2769)]. These smoke constituents are of particular concern because of their alkylating potential. Maleic anhydride, 2,3-dimethylmaleic anhydride and succinic anhydride have produced local tumours in one experiment in rats [Dickens and Jones (7A01, 7A02), I ARC (7A03)]. 

The oxidation of dimethylmaleic acid (H2A) and anhydride obeys the rate law... 

Alder diadduct, 108 3,4-Dimethylhexane, 169 A, A -Dimethylhydrazine, reaction with MA, 84 )3(2,4-Dimethyl-6-hydroxybenzoyl)acrylic acid, 94 )3(2,6-Dimethyl-4-hydroxybenzoyl acrylic acid, 94 Dimethylmaleic acid, 238 Dimethylmaleic anhydride alternating copolymerization, 307 diazoalkane adducts, 222 MA in synthesis, 238 photochemical reactions, 182 polymerization attempts, 263 Dimethylmaleimide,A-(2-pyradinyl), MA in synthesis, 238... 

Maleic anhydride is decomposed in the Hquid phase by various nitrogen bases. Treatment of maleic anhydride in refluxing acetic acid with 2-anainopyridine [504-29-0] gives, after work-up in 4 at 100°C, the decarboxylative dimeri2ation product, 2,3-dimethylmaleic anhydride [766-39-2]... 

The first successful attempt to prepare bicyclic indolizinedione derivatives 210 was achieved by the reaction of dimethylmaleic anhydride with pyrrolylmagnesium bromide followed by the cyclization of the intermediate acid. The corresponding unsubstituted desmethyl compound cannot be prepared this way [90JCS(P1) 1463]. 

Other five-membered heterocyclic enones used in [2 + 2] photocycloadditions are 1//-pyrrole-2,3-diones86-88 and derivatives of maleic anhydride. Some cycloadducts of dimethylmaleic anhydride and unsaturated acid esters have been used as monomers for condensation polymers.89... 

These investigators found that the normal acids occurred in much greater abundance than the branched acids. The cyclic acids isolated by Lochte and coworkers (31) include cyclopentanecarboxylic acid, 2-methylcyclopentanecarboxylic acid, 3-methylcyclopentane-carboxylic acid, cyclopentaneacetic acid, 3-methylcyclopentaneacetic acid, 2,3-dimethyl-cyclopentaneacetic acid, 1,2,2-trimethylcyclopentanecarboxylic acid, cyclohexanecarbox-ylic acid, p-methylcyclohexanecarboxylic acid, and the cis and trans forms of 2,2,6-tri-methylcyclohexanecarboxylic acid. In addition, Lochte and coworkers (31) isolated dimethylmaleic anhydride, which has also been isolated by Nenitzescu and coworkers (42). 

The degradation process for a series of organic anhydrides (dimethylmaleic anhydride and acid, maleic anhydride and acid, crotonic acid, methylacrylic anhydride and acid, citroconic anhydride and acid) commonly used in industry were followed using a Cjg column (A = 220nm) and a 70/30 water (lOmM ammonium phosphate at pH 2.5)/acetonitrile mobile phase [892]. Each pair (anhydride and acid) was chromatographed separately and all were well resolved under these, conditions. Elution took from 5 to 22 min depending on the analytes. Injections of 25 nmol generated peaks about 0.002 AU. 

Of particular interest is the oxidation of the complexes Fea CjoH R Og (XXXI R = R = CH3 or H) with aqueous ferric chloride to give a product of composition (RC2R)Fe(CO)6 [190). Oxidation of the dimethyl derivative with cold concentrated nitric acid gives dimethylmaleic anhydride (XXXII). The derivative (HC2H)Fe(CO)6 forms a Diels-Alder adduct (XXXIII) with cyclopentadiene the adduct may be oxidized to succinic acid. All of these data indicate that the derivatives (RC2R)Fe(CO)6 are cyclic derived from maleic acid derivatives. Four of the six carbonyl groups are metal... 

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