To a solution of 690 mg (2.33 mmol) of N-(2- benzhydroxyethyl)piperazine in dry dimethylformamide (2 ml) was added 1.75 g (3.26 mmol) of N-[5-[3,4-bis(βmethoxyethoxymethoxy)phenyl]-2,4-pentadienoyl]thiazolidine-2-thione, and the mixture was reacted at room temperature 18 hours under argon atmosphere. The reaction mixture was concentrated by evaporation under reduced pressure and the residue was subjected to silica gel column chromatography. There was obtained from fractions eluted with chloroform - methanol (100:1) 856 mg (1.30 mmol) of N-[5-[3,4-bis(β-methoxyethoxymethoxy)phenyl]-2,4-pentadienoyl]-N'-(2-benzhydroxyethyl)piperazine. To a solution of 856 mg (1.30 mmol) of the amide compound in methanol (17 ml) was added 257 mg (1.35 mmol) of p-toluenesulfonic acid monohydrate, and the mixture was refluxed for 4 hours. A saturated aqueous solution of sodium chloride was added to the reaction mixture, which was adjusted to a pH value of 10 by the addition of an aqueous solution of sodium carbonate, and then extracted with ethyl acetate. The organic layer was washed with water and concentrated by evaporation under reduced pressure. The residue was subjected to Sephadex column chromatography, eluted with methanol, to give 439 mg (0.906 mmol) of N-[5-(3,4-dihydroxyphenyl)-2,4-pentadienoyl]--N'-(2-benzhydroxyethyl)piperazine. Spectrophotometric data of the product support the structure shown below. ##STR97##
