Veratric Acid → 6-[4-(3,4-Dimethoxybenzoyl)-1-piperazinylcarbony]-3,4-dihydrocarbostyril

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Reaction Steps

1.8 Grams of 3,4-dimethoxybenzoic acid and 2.75 g of 6-(1-piperazinylcarbonyl)-3,4-dihydrocarbostyril were added to a mixed solvent of 20 ml of dioxane with 20 ml of methylene chloride. Under the condition that the outside of reaction vessel was ince-cooled with stirring, a solution of 2.1 g of N,N-dicyclohexylcarbodiimide being dissolved in 5 ml of methylene chloride by keeping its temperature to 10°-20° C. was added dropwise thereto and stirred at the same temperature for 3.5 hours. The crystals formed in the reaction mixture were removed by filtration, and the mother liquor was concentrated under a reduced pressure. The residue thus obtained was dissolved in 100 ml of methylene chloride and the organic layer was washed with 5%-hydrochloric acid aqueous solution, 5%-sodium hydrogen-carbonate aqueous solution and water in this order, then the organic layer was dried with anhydrous sodium sulfate. The solvent was removed by distillation under a reduced pressure and the residue thus obtained was recrystallized from chloroform-ethanol to obtain 0.9 g of 6-[4-(3,4-dimethoxybenzoyl)-1-piperazinylcarbonyl]-3,4-dihydrocarbostyril. Colorless granular crystals. Melting point: 238°-239.5° C.

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