Triethylamine → N-(tert-Butoxycarbonyl)-4-nitro-L-phenylalanine

Participants

Reaction Steps

To a stirred suspension of 50.45 g (240 mmole) of 4-nitro-L-phenylalanine in 140 ml water was added a solution of 65.11 g (264.4 mmole; 1.1 eq) of BOC-ON in 140 ml dioxane and 53 ml (380.3 mmole; 1.58 eq) of Et3N. The gradually cleared solution was stirred at room temperature for 4 hours. The reaction mixture was poured into 410 ml water and extracted with ether (5×330 ml). The aqueous layer was acidified to pH 1.15 with 6N HCl and then extracted with EtOAc (5×330 ml). The EtOAc extracts were pooled and dried over with MgSO4, filtered and evaporated under reduced pressure to give a crude residue. This residue was dissolved in 300 ml ether, the solvent was removed under reduced pressure to give 67.61 g (90.8%) product (1) as a pale yellow foam. 1HNMR (CDCl3, δ)=8.17 & 7.38 (d & d, 4H), 5.15 & 4.55 (m & m, 2H), 3.20 (m, 2H), 1.38 (2s, 9H).

Provenance & Evidence