p-Toluenesulfonic acid → HCID 15755271, compound

Participants

Reaction Steps

Boc-D-Trp(CHO)-OH (2.99 g), TsOH.H-Phe-OBzl (3.85 g, and HOBT (1.22 g) were dissolved in a mixed solvent of methylene chloride (60 ml) and DMF (15 ml). To this solution was added WSC (1.53 g) under ice cooling, and the reaction mixture was stirred for 3 hours at the same temperature. The reaction mixture was concentrated and extracted with ethyl acetate. The organic layer was washed successively with diluted sodium hydrogencarbonate solution (twice), water, 0.5N hydrochloric acid, and saturated sodium chloride solution, and dried over magnesium sulfate. After concentration, the residue was crystallized from a mixture of ethyl acetate and diisopropyl ether (1:1), which was filtered, washed with diisopropyl ether, and dried to give Boc-D-Trp(CHO)-Phe-OBzl (4.95 g).

Provenance & Evidence