4-((1R)-1-Aminoethyl)phenol → (R)-N2-(Boc)-N5-(Cbz)-(R)-N-[1-(4-hydroxyphenyl)ethyl]ornithine amide

Participants

Reaction Steps

Nα -Boc-Nδ -Cbz-(R)-ornithine o-nitrophenyl ester (33 g; 66.8 mmol; from step (a) above) and (R)-4-hydroxy-α-methylbenzylamine (9.3 g; 68.2 mmol) were combined in CH2Cl2 (600 mL). The resulting yellow solution was stirred at room temperature for 4 hours. When the coupling was complete, as determined by TLC, the solution was concentrated under vacuum to give the crude product. The crude material was dissolved in EtOAc, washed with 0.5N NaOH (2×300 mL), saturated KHSO4 (2×300 mL), brine (2×300 mL), dried over Na2SO4, filtered and concentrated to yield 30.1 g (61.9 mmol; 93%) of the sub-title compound.

Provenance & Evidence