反应详情

To a solution of (R)-N2 -(Boc)-(R)-N-[1-(4-hydroxyphenyl)ethyl]ornithine amide (11.47 g; 0.33 mmol; from step (a) above) in DMF (50 mL) was added N,N'-bis(Cbz)-S-methylisothiourea (11.8 g; 0.33 mmol). The solution was stirred overnight at room temperature followed by removal of the solvent under reduced pressure. The resultant oil was chromatographed on a plug of silica gel (7.5 cm×12.5 cm) eluting first with CH2Cl2 (800 mL) to remove the higher Rf impurities. The eluent was switched to EtOAc (600 mL) to elute the sub-title compound as a white foam (14.67 g).

1. customfollowed by removal of the solvent under reduced pressure
2. customThe resultant oil was chromatographed on a plug of silica gel (7.5 cm×12.5 cm)
3. washeluting first with CH2Cl2 (800 mL)
4. customto remove the higher Rf impurities
5. washto elute the sub-title compound as a white foam (14.67 g)