Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

In 50 ml of dimethylformamide were dissolved 8.1 g of 5-carboxybenzotriazole and 15.3 g of the amino compound obtained in above step 4-(2) and while stirring the solution at 0° C. in a nitrogen gas atmosphere, 5 ml of dimethylformamide solution containing 10.3 g of dicyclohexylcarbodiimide were added dropwise to the solution over a period of 15 minutes. After stirring the mixture for one hour, the mixture-was further stirred for 2 hours at 25° C. Then, dicyclohexylurea formed was removed by filtration and the filtrate thus obtained was added to 1.5 liters of ice water. Crude crystals thus deposited were collected by filtration and dispersed in 100 ml of isopropanol for 15 minutes under heating. The reaction mixture was cooled to room temperature and filtered to provide 12.1 g of desired Compound 201 having a melting point of from 196° C. to 199° C. (decompd.) with the yield of 54%.

Provenance & Evidence