Dicyclohexylcarbodiimide → 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 α-bromo-propionylethylamide 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 192° C. Then, 0.01 mole of 1-hydroxy-4-[1-(ethylaminocarbonyl)ethoxy]-2-naphthoic acid so obtained was dissolved in 60 ml of dry dioxane, and 0.01 mole of dicyclohexylcarbodiimide was added to the solution. The reaction was conducted at 50° to 60° C. for 30 minutes under agitation. After completion of the reaction, the reaction mixture was filtered and dicyclohexylurea formed as a by-product was removed. The filtrate was concentrated under reduced pressure and n-hexane was added. Precipitated crystals were recovered by filtration and recrystallized from n-hexane to obtain a compound having a melting point of 95° C. (the yield being 65%). From the results of the elementary analysis, it was confirmed that the compound was the compound (2) illustrated above.

Provenance & Evidence