2-sulfonic-benzoic anhydride

The Heck reaction is a C-C coupling reaction where an unsaturated hydrocarbon or arene halide/triflate/sulfonate reacts with an alkene in presence of a base and Pd(0) catalyst so as to form a substituted alkene. Kaufmann et al. showed that the Heck reaction carried out in presence of ILs such as tetra-alkyl ammonium and phosphonium salts without the phosphine ligands, resulted in high yields of product. They attributed the activity to the stabilizing effect of ammonium and phosphonium salts on Pd(0) species. Carmichael et al. used ionic liquids containing either A,A -dialkylimidazolium and A-alkylpyridinium cations with anions such as halide, hexafluorophosphate or tetrafiuoroborate to carry out reactions of aryl halide and benzoic anhydride with ethyl and butyl acrylates in presence of Pd catalyst. An example of iodobenzene reacting with ethyl acrylate to give trans-et vy cinnamate is shown in Scheme 14. 

Polynaphthylimide with iV-naphthylimide orfho-sutetituents was prepared by the reaction of 3,3 -diamino-4,4 -di(p-aminophenoxy) diphenyl sulfone [164] with an equimolar amount of bis(naphthalic anhydride) followed by treatment with a two-fold molar amount of naphthalic anhydride in a m-cr ol-benzoic acid medium under the conditions of high-temperature catalytic polycondensation. The polymer was soluble in phenolic, amide solvents as well as in tetrachloroethane its molecular mass was of the order of 60 000, the softening temperature 340 °C and the temperature of 10 % mass loss 480 °C (Table 16). 

Based on its availability and structural nature, investigation of the " dehydrating power of o-sulfobenzoic acid anhydride (I) was carried out The parent add may be readily available as an intermediate in the synthesis of saccharin (5). The cyclic nature of this anhydride along with its half sulfonic/ half benzoic composition hinted to us that it may prove to be a suitable compound for the present isocyanate technology. 

An ethereal suspension of thallous benzoate (prepared from benzoic acid and thallous ethoxide) treated 6 hrs. at 25° with the stoichiometric amount of iso-butyryl chloride benzoic isobutyric anhydride. Y ca. 100%. - To minimize comproportionation, the carboxylate salt of the weaker acid should be used. F. e., also phenolesters and phenyl sulfonates with thallous phenoxides, as well as sym. carboxylic acid anhydrides from thallous carboxylates with SOCU, s. E. G. Taylor, G. W. McLay, and A. McKillop, Am. Soc. 90, 2422 (1968). 

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