Dimethylformamide → 3-(4-Benzyloxy-phenyl)-2-{2-[(9H-fluoren-9-ylmethyl)-amino]-4-methyl-pentanoylamino}-propionic acid tert-butyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of FMOC-leucine (10.3 g, 29 mmol) in 300 mL of DMF was cooled to 0° C. and treated with diisopropylethyl amine (73 mL) and HBTU (11.1 g, 29.2 mmol). The resulting solution was stirred at 0° C. for 30 minutes and treated with the product from Example A ((S)-2-amino-3-(4-benzyloxy-phenyl)-propionic acid tert-butyl ester) (11.0 g, 36.9 mmol). The resulting solution was stirred for 30 minutes at 0° C. and warmed to room temperature. The reaction mixture was poured into 500 mL of ether and washed sequentially with 1N aqueous HCl, saturated aqueous NaHCO3 (100 mL) and brine (5×100 mL). The organic phase was collected, dried MgSO4 and concentrated to near dryness. The residue was triturated with hexane. The product was collected by suction filtration and air dried to give the title compound as a white solid (12.16 g, 70%), mp=158-160° C.

Provenance & Evidence