Dimethylmaleate

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]... 

Benzo[c]furan, generated in situ in boiling xylene in the presence of dimethylmaleic anhydride, gives mainly the exo adduct furan itself fails to react with this dienophile (Scheme 53) (82JOC4011. l,3-Diphenylbenzo[c]furan is also a reactive diene but the corresponding 1,3-dimesityl derivative is inert to several dienophiles, even under forcing conditions (82CC766). 

The photochemically induced [2 + 2] cycloaddition of selenophene with dimethylmaleic anhydride gives a 1 1 adduct (140), but attempts to form an oxetane by photoreaction with benzophenone failed (80JHC1151). 

Dimethylmaleic anhydride [766-39-2] M 126.1, m 96 , b 225 /760mm. Distd from benzene/ligroin and sublimed in a vacuum. 

With dimethylmalic acid lyase (EC 4.1.3.32) from Clostridium harkeri. an enzyme involved in nicotinic acid metabolism, propanoate can be added to pyruvate yielding stereospecifically the (2i ,3S)-dimethylmalic acid39. 

Dimethylmaleate, 58,74 D1METHYL(METHYLENE)AMM0N1UM TRIFLUOROACETATE, 59, 153 o-Dimethyl 2-nitropentanedioate, 57, 62 Dimethyl 4-nitropimelate, 56, 39 DIMETHYL NITROSUCCINATE, 57, 60... 

Cyclopentadiene adds to dimethylmaleic anhydride to produce cyclobutane dimer (84) and two products from l,4-cycloaddition<97) ... 

Endo product (86) is thought to result from thermal addition and is probably not a photoproduct. Cyclohexadiene yields cyclobutanes (87)—(89) and 1,4-cycloaddition product (90) with dimethylmaleic anhydride(87> ... 

Photocycloadditions of maleic anhydride and dimethylmaleic anhydride to various other substituted cyclohexadienes and to cycloheptatriene have also been reported/58,97 98 ... 

Homer and Roder also found that dimethylmaleic acid 112, R = H) and its methyl ester 112, R = CH3) are reduced stereospecifically to meso-2,3-di-methylsuccinic acid and its methyl ester, respectively 113, R = H and CH3)ll7>. 

These results, which correspond to stereospecific cis addition of hydrogen to the double bond, stand in direct contradiction to the report st> by Elving and coworkers that dimethylmaleic acid 112, R = H) affords dl-113 (R = H) exclusively and that dimethylfumaric acid affords only meso-113 (R = H). The latter results correspond of course to stereospecific tram addition of hydrogen across the double bond. Camilli, like Homer and R6der, however, observed c/s-addition of hydrogen, albeit in a slightly different system, 18> ... 

During work-up after ozonolysis of the lactone to give dimethylmaleic anhydride, removal of excess ozone by a stream of oxygen leads to the precipitation of peroxidic material at the concentration used in the preparation. 

Meyer M, Zintchenko A, Ogris M, Wagner E (2007) A dimethylmaleic acid-melittin-polylysine conjugate with reduced toxicity, pH-triggered endosomolytic activity and enhanced gene transfer potential. J Gene Med 9 797-805... 

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]. 

The formation of meso-dimethylsuccinic acid from dimethylmaleic acid and the racemic mixture from dimethylfumaric acid implies that both hydrogen atoms add to the same side of the unsaturated molecule 11). Bourguel (12) also noted that disubstituted acetylenes yielded initially cis-ethylenes but that trans isomers were formed if the hydrogenations were protracted. 

These authors, using a horn system, also noted less striking but still significant switches towards the one-electron products in other sonoelectrochemical reductions [66] including dimethylmaleate at a lead cathode in an aqueous mixed-phosphate buffer, and benzyl bromide at a lead cathode in methanolic tetraethylammonium bromide solution (Tab. 6.16). 

This enzyme [EC 5.3.3.6] catalyzes the interconversion of methylitaconate and dimethylmaleate. 

Acetone-sensitized [2+2]-photocycloaddition of 2(3//)-oxazolones 247a to maleic anhydride and dimethylmaleic anhydride gives the corresponding anti-cyclobutane cycloadducts 253 as the major products. Similar photoreaction of 2(37/)-oxazolones with 1,6-anhydro-4-(9-benzyl-2,3-dideoxy- 3-D-e 7t/ira-2-hex-enopyranose 254 results in the exclusive formation of the anh-cyclobutane-type adduct 255 (Fig. 5.61). ... 

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). 

Diels-Alder route to cantharidin. Use of high pressure to facilitate. Diels-Alder reactions has led to a simple synthesis of cantharidin.1 The obvious dienophile component, dimethylmaleic anhydride, is unreactive to furane even under high pressure, but 2,5-dihydrothiophene-3,4-dicarboxylic anhydride (l)2 reacts with furane at 25° under 15 kbar of pressure to give the exo-adduct (2) and the endo-isomer as a 85 15 mixture. The major adduct is converted into cantharidin (3) by reduction and desulfurization over Raney nickel in 63% overall yield. 

In view of the inherent properties of the system, many attempts have been made to extend the shade range commercially but with little success. An example is the purple nickel chelate (65) derived from dimethylmaleic anhydride (B-71MI11207). 

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