A mixture of 1 g of 5-{4-[6-hydroxy-4-(E)-hydroxyimino-2,5,7,8tetramethylchroman-2-ylmethoxy ]benzyl}-thiazolidine-2,4-dione (prepared as described in Example 13), 1.7 g of benzoyl bromide, 10 ml of pyridine and 5 ml of dimethylformamide was allowed to stand for 6 days at room temperature, after which it was heated for 8 hours at 60°-80° C. An aqueous solution of potassium carbonate and ethyl acetate were then added to the reaction mixture. The organic layer was separated and dried over anhydrous sodium sulfate. The solvent was distilled off and the residue was purified by silica gel column chromatography eluted with a 4:3 by volume mixture of hexane and ethyl acetate, to give the title compound, softening at 101°-107° C.
