Functional Polymers V. Preparation and Polymerization of Methyl 4-Vinylsalicylate, 4-Vinylsalicylic Acid and 4-Vinylacetylsalicylic Acid

Methyl 4-vinylsalicylate, 4-vinylsalicylic acid, and 4-vinylacetylsalicylic acid were prepared in overall yields of 28%, 21 % and 16%, respectively, starting with 3-ethylphenol. Radical polymerization of all three monomers was investigated. Methyl 4-vinylsalicylate and 4-vinylsalicylic acid polymerized normally via radical initiation, giving soluble polymers of high molecular weight. 4-Vinylacetylsalicylic acid gave gelled polymerization mixtures in tert-butanol and in dimethyl sulfoxide, using the same experimental procedure; this was shown to be a result of intermolecular transesterification during polymerization. A water-insoluble copper complex of poly(4-vinylsalicylic acid) was prepared. Methyl 4-vinylacetylsalicylate was also synthesized, in 35% yield, but no polymerization experiments were performed with this monomer. These new polymeric salicylic acid derivatives are of interest as ultraviolet stabilizers, as protective agents for the skin, as metal-complexing agents, and as potential medicinal agents