Dicyclohexylcarbodiimide → N,N'-Dicyclohexylurea

Participants

Reaction Steps

The preparation is preferably carried out in the following way: The starting camptothecin compound, preferably 2 to 10 molar equivalent of the reacting aromatic acid of the general formula C6R2-6COOH, preferably 2 to 8 molar equivalent of DCC, and a catalytic amount of DMAP are added to about 60-100 ml DMF in a 250 ml round-bottomed flask equipped with a mechanical stirrer. The mixture is stirred at room temperature under nitrogen gas for 72-96 hr. Dicyclohexyl urea formed is removed by filtration. The filtrate is poured onto 500-800 ml ice water while stirring. The crude product is collected by filtration, air-dried at room temperature, then separated by column chromatography with THF-C2H2 (from 1:7 to 1:15) as eluent. The pure ester prodrug is obtained as white or yellow powders after precipitation from petroleum ether. Reaction yields can range from 5 to 98%.

Provenance & Evidence