2,2-Diphenylacetyl chloride → (R)-N5-(Cbz)-N2-(Diphenylacetyl)-N-methyl-(S)-N-(1-phenylethyl)-ornithine amide

Participants

Reaction Steps

Prepared according to the method described in Examples 2(b) and 2(c) above from (R)-N2 -(Boc)-N5 -(Cbz)-N-methyl-(S)-N-(1-phenylethyl)-ornithine amide (5.3 g; 11 mmol; from step (a) above), EtOAc (75 mL), then HCl/EtOAc (75 mL), 2.5 hours reaction time for the deprotection, then CH2Cl2 (50 mL), diphenylacetyl chloride (2.6 g; 11 mmol) followed by pyridine (3.0 mL; 37 mmol; instead of DiPEA) over 1 min, overnight reaction time, diluted with CH2Cl2 (100 mL) for the work-up procedure. The crude material was purified by chromatography on silica gel with EtOAc:hexane (1:1) to provide 1.9 g (30%) of the sub-title compound.

Provenance & Evidence