Benzoic Acid → N,N'-Dicyclohexylurea

Participants

Reaction Steps

Camptothecin (0.8 g, 0.0023 mol), benzoic acid (1.8 g, 0.014 mol), DCC (1.2 g, 0.0058 mol), and DMAP (0.3 g, 0.0025 mol) were added to 60 ml DMF in a 250 ml round-bottomed flask equipped with a mechanical stirrer. The mixture was stirred under N2 at room temperature for 72 hr. Dicyclohexyl urea formed during the reaction was removed by filtration. The filtrate was poured onto 600 ml ice water while stirring. The stirring was maintained for 30 min. The crude product was collected by filtration. The residue was chromatographically separated with THF-CH2Cl2 (1:15) as eluent. The pure product (0.4 g) was obtained as white powders by precipitation from petroleum ether. Yield 38%. Mass m/e (relative intensity): 452 (m+, 25), 330 (100), 315 (35), 302 (60), 287 (40), 169 (12), 122 (36), 105 (70), 77 (35), 69 (26); precise mass (C27H20N2O5): found, 452.137; required, 452.137.

Provenance & Evidence