Hydrochloric Acid → N(alpha)-(N(alpha)-(N(alpha)-(tert-butyloxycarbonyl)glutaminyl)-N(1)-formyl-tryptophyl)phenylalanine benzyl ester

Participants

Reaction Steps

To a solution of Boc-Gln-OH (2.10 g), HCl.H-D-Trp(CHO)-Phe-OBzl (4.70 g) and HOBT (1.15 g) in a mixed solvent of methylene chloride (60 ml) and DMF (10 ml), was added WSC (1.41 g) under ice cooling. The reaction mixture was stirred for 1.5 hours at the same temperature and for additional 1.5 hours at room temperature and concentrated under reduced pressure. Water was added to the residue and the resulting precipitates were collected and washed successively with water, diluted sodium hydrogencarbonate solution and water. After drying, the crude product (5.84 g) was stirred in hot ethyl acetate (60 ml) in water bath. After cooling, the precipitates were collected by filtration and dried to give Boc-Gln-D-Trp(CHO)-Phe-OBzl (5.70 g).

Provenance & Evidence