Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

In 20 ml of anhydrous tetrahydrofuran were dissolved 430 mg (1 millimole) of 3-hydroxy-2-(2-tritylaminothiazol-4-yl)propionic acid, 510 mg (1 millimole) of 7β-amino-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-Δ3 -cephem-4-carboxylic acid benzhydryl ester, and after adding thereto 206 mg (1 millimole) of N,N'-dicyclohexylcarbodiimide, the mixture was stirred for 3 hours at room temperature. The reaction mixture was concentrated under reduced pressure and then 40 ml of ethyl acetate was added to the residue. Insoluble N,N'-dicyclohexylurea formed was filtered off and the filtrate was washed with a diluted aqueous acid solution and an aqueous solution of sodium hydrogencarbonate and dried by anhydrous magnesium sulfate. The solvent was distilled off under reduced pressure and then, the residue was treated with ether to form a powder, which was recovered by filtration, and washed with water to provide 720 mg of 7β-[3-hydroxy-2-(2-tritylaminothiazol-4-yl)propionamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-Δ3 -cephem-4-carboxylic acid benzhydryl ester.

Provenance & Evidence