1,4-Dihydroxy-2-naphthoic acid → N,N'-Dicyclohexylurea

Participants

Reaction Steps

0.05 mole of 1,4-dihydroxy-2-naphthoic acid was dissolved in 70 ml of DMF, and 10 ml of a 40% aqueous solution of sodium hydroxide was added dropwise to the solution while introducing nitrogen gas. Then, 0.05 mole of diethyl α-bromo-succinate dissolved in 15 ml of DMF was added dropwise, and the reaction was conducted at 50° C. for 3 to 4 hours under agitation. After completion of the reaction, the reaction mixture was poured into ice-hydrochloric acid, and crystals were recovered by filtration and recrystallized from acetonitrile to obtain a compound having a melting point of 176° C. Then, 0.01 mole of the so obtained compound and 0.01 mole of n-dodecylbutylamine were dissolved in 60 ml of dry dioxane, and 0.01 mole of dicyclohexylcarbodiimide was added to the solution and the reaction was carried out at 50° C. for about 30 minutes. After completion of the reaction, the reaction mixture was filtered and dicyclohexyl urea formed as a by-product was removed. The filtrate was concentrated under reduced pressure and separated by column chromatography to obtain a compound having a melting point of 68° C. (the yield being 35%). From results of the elementary analysis and the like, it was confirmed that the so obtained compound was the compound (4) illustrated above.

Provenance & Evidence