Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

To a solution of 48 g. (181 mmole) of 3-benzoyl-2,2-dimethyl-4-thiazolidinecarboxylic acid, prepared by the procedure described by Example 1, in 1.5 l. of tetrahydrofuran were added 27.8 g. (181 mmole) of 1-hydroxybenzotriazole followed by 37.4 g. (181 mmole) of dicyclohexylcarbodiimide. The mixture was stirred for 30 minutes at room temperature. The reaction mixture developed into a thick slurry resulting from the precipitation of dicyclohexylurea. To the heavy slurry was added 63 g. (181 mmole) of benzyl D-4-benzyloxyphenylglycinate and the reaction mixture was stirred at room temperature for about 2 hours. The reaction mixture was filtered to remove the dicyclohexylurea, the filtrate evaporated under reduced pressure, and the residue was dissolved in ethyl acetate. The solution was washed successively with 5% hydrochloric acid, water, aqueous sodium bicarbonate, and finally with water. The washed solution was dried, treated with carbon, and evaporated to dryness under reduced pressure to yield 107 g. (99% yield) of N-[α-(benzyl D-4-benzyloxyphenylacetate]- 3-benzoyl-2,2-dimethyl-4-thiazolidinecarboxamide.

Provenance & Evidence