Hydrochloric Acid → 1-Benzyl-3(S)-(2'-methylbenzyl)-piperazine-2,5-dione

Participants

Reaction Steps

A solution of Boc-2-methyl-L-phenylalanine (2.79 g, 10 mmol) in DMF (25 mL) was treated sequentially with HOBt (2.03 g, 15 mmol), diisopropylethylamine (4.35 mL, 25 mmol), N-benzylglycine ethyl ester (2.03 mL, 11 mmol), and HBTU (5.69 g, 15 mmol). The resulting solution was allowed to stir for 16 h after which time the mixture was poured onto a mixture of a 1 N aqueous HCl (50 mL) solution and EtOAc (50 mL). The organic portion was separated and further extracted with a saturated aqueous NaHCO3 solution (50 mL) follow by brine (50 mL). The organic phase was dried over MgSO4, filtered and evaporated to an oil, which was purified by silica gel flash chromatography with 20% then 30% EtOAc/hexanes as eluant to afford titled compound as a solid (4.31 g, 95%). LC/MS (Method A) 7.43 min, [M+1]+ 455.

Provenance & Evidence