Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Symmetrical carbonates were formed when the corresponding carbonochloridates containing electron-withdrawing groups were converted with tertiary amines in dry solvents at room temperature. 5-Norbornene-2,3-dicarboximido carbonochloridate (1) and bis(5-norbornene-2,3-dicarboximido) carbonate (5) were used for acylation of OH groups in polymers in the presence of tertiary amines under anhydrous conditions. The influence of the amounts of 1 and 5, the kind and amount of amines, the organic solvent, the reaction time and temperature on the yield of the active carbonate 7 was investigated using bead cellulose as polymer. The reaction based on the catalysis by strongly nucleophilic amines such as 4-dimethylaminopyridine (DMAP) was optimized for preparation of acylated polymers. The formation of cross-linking and cyclic carbonates 9 and 10, respectively, was observed as a side reaction. It was shown that carbonates 9 and 10 can also be obtained as the main products of acylation. The preparation of 9 was also carried out by treating 7 with an excess of DMAP. Examples are presented for the transesterification of 7 with compounds containing OH groups. The acylated polymers were characterized by a specific titration method, UV/VIS and IR spectroscopy. The mechanism of the DMAP-catalyzed acylation of polymers is discussed.
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