2,2-Diphenylacetyl chloride → (R)-N5-(Cbz)-N2-(Diphenylacetyl)-N-methyl-(R)-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-(R)-N-(1-phenylethyl)ornithine amide (5.0 g; 10 mmol; from step (a) above) EtOAc (75 mL) then HCl/EtOAc (75 mL), 2 hours reaction time for the deprotection, then CH2Cl2 (50 mL), diphenylacetyl chloride (2.4 g; 10 mmol) followed by pyridine (3.0 mL; 37 mmol; instead of DiPEA) over 1 minute, 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:hexanes (1:1) to provide 1.6 g (26%) of the sub-title compound.

Provenance & Evidence