Dimethylsuccinic anhydride

Hydrogenation of phthalic anhydride over copper chromite afforded 82.5% yield of the lactone, phthalide, and 9.8% of o-toluic acid resulting from hydrogenolysis of a carbon-oxygen bond [1015]. Homogeneous hydrogenation of a,a-dimethylsuccinic anhydride over tris(triphenylphos-phine)rhodium chloride gave 65% of a,a-dimethyl- and 7% of )S,)S-dimethyl-butyrolactone [1016]. 

A Variety of ketones may be made using cadmium alkyls (50-70%). In the preparation of alkyl aryl ketones, reaction of the aliphatic rather than the aromatic anhydride is preferred. Keto acids result when phthalic anhydride or dimethylsuccinic anhydride (60-70%) is used. 

For example, Kunitake used the shifts on going from a trans-to a ciA-l,2-dimethylcyclopentane as representative of that which would occur in an analogous 2,3-dimethylsuccinic anhydride. Thus he estimated a shift of -5.1 ppm for C-2 (and C-3) and -2.1 ppm for the carbonyl carbon. We found that the actual shifts on going from trans- to cis-2,3-dimethylsuccinic anhydride are -4.1 ppm (C-2 and C-3) and +1.1 ppm (carbonyls). 

Earlier methods for the prediction of rotation, devised by Kirkwood and Eyring are apparently regarded by organic chemists as too inconvenient for routine use. However, the Kirkwood method was successfully applied to (+)-2,3-dimethylsuccinic anhydride. The Kirkwood-Eyring approach has been improved by Yamana. The values predicted seem to be precise however, carbohydrate chemists may still prefer the more convenient Whiffen-Brewster approach. 

The intermediate nickelacycles decompose by P-hydride elimination to form mixtures of alkenes. For example, tranj-dimethylsuccinic anhydride reacts with Ni(CO)j(PPh3)2 to form a 10 10 1 mixture of trans-and ds-2-butene and 1-butene (Scheme 4). The formation of these alkenes indicates that an intermediate nickel hydride, such as the one shown in Scheme 4, is involved because control experiments demonstrate that no isomerization of the alkenes takes place under the reaction conditions. ... 

Low molecular weight reactants such as phthalic anhydride and dimethylsuccinic anhydride were used as model compounds for trimellitic anhydride terminated polystyrene and styrene-maleic anhydride (SMA) copolymer. As amine functional species, benzyl-amine and 1,2 diphenylethylamine, were employed, the transposal of the knowledge gained from model compounds to a real polymer blend system reacted in the melt under shear was only slightly instmctive. The low reactivity observed in the case of the reactive polymers has been ascribed to a chemically different environment and not to a diffusion-controlled process as is generally considered. 

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