1,2-Dichloroethane → N-Acetyl-D-thioproline (O-benzyl)-L-tyrosine methyl ester

Participants

Reaction Steps

EDC (211 mg, 1.1 mmol) was added to a stirred solution of N-acetyl-D-thioproline (175 mg, 1 mmol), O-benzyl tyrosine methyl ester hydrochloride (322 mg, 1 mmol), HOBT (149 mg, 1.1 mmol) and NMM (242 μl, 2.2 mmol) in DCM (10 ml) at 0°. The mixture was stirred at room temperature overnight then diluted with DCM (100 ml). The DCM solution was washed with 1M hydrochloric acid (30 ml), saturated aqueous NaHCO3 (30 ml) and water (30 ml), dried (Na2SO4) and evaporated in vacuo. The residue was purified by chromatography (SiO2 ; ethyl acetate) to give the title compound as a white foam (417 mg, 94%); δH (DMSO-d6, 300K) (2 rotameric species observed) 8.55 (d. J 7.8 Hz) and 8.28 (3, J 8.1 Hz) together (1H, NHCO), 7.43-7.25 (5H, m, Ph), 7.14-7.08 (2H, m, ArH), 6.92-6.88 (2H, m, ArH), 5.06 (2H, s, CH2Ph), 4.79-4.66 (m) and 4.45-4.42 (m) and 4.21 (d, J 9.7 Hz) together (4H, CHα-tyr, CHα-thiopro and NCH2S), 3.62 (s) and 3.61 (s) together (3H, CO2Me), 3.28-2.71 (4H, m, CHCH2Ar+CHCH2S) and 2.04 (s) and 1.82 (s) togher (3H, CH3CO); m/z (ESI, 15V) 443 (M+ +1).

Provenance & Evidence