Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

A synthetic aldehyde, Pro4-de novo CHO, was prepared as follows. To a stirred solution of 5-carboxyfluorescein (5-FAM) (190 mg, 0.51 mmol) in anhydrous N,N-dimethylformamide (DMF (5 mL) were added N-hydroxysuccinimide (NHS) (77 mg, 0.67 mmol) and 1,3-dicyclohexylcarbodiimide (DCC) (126 mg, 0.61 mmol). After approximately 5 minutes, a white solid (dicyclohexylurea) started forming. The reaction mixture was stirred overnight under nitrogen. Thin layer chromatography (TLC) (40:9:1 CH2Cl2—CH3OH-water) indicated complete disappearance of the starting material. The mixture was then filtered, and the filtrate was added dropwise to a stirred solution of ethylene diamine (46 mg, 0.77 mmol) in DMF (3 mL). A solid was obtained. As evident from TLC, the reaction was complete instantaneously. This reaction mixture was subsequently treated with glyoxylic acid NHS ester prepared below.

Provenance & Evidence