1,2-Dichloroethane → N-Acetyl-D-thioproline L-tyrosine tert.butyl ester

Participants

Reaction Steps

EDC (4.22 g, 22 mmol) was added to a solution of N-acetyl-D-thioproline (3.50 g, 20 mmol), tyrosine tert.butyl ester (4.74 g, 20 mmol), HOBT (2.97 g, 22 mmol) and NMM (2.42 ml, 22 mmol) in DMF (80 ml) at 0°. The mixture was stirred at room temperature overnight. The DMF was evaporated in vacuo and the residue dissolved in ethyl acetate (600 ml) and water (50 ml). The organic phase was washed with 10% citric acid (150 ml), saturated aqueous NaHCO3 (150 ml), water (150 ml) and brine (150 ml), dried (Na2SO4) and evaporated in vacuo to give the title compound as an off-white solid (7.39 g, 94%); δH (DMSO-d6, 300K) (2 rotameric species observed) 9.17 (1H, br s, ArCH), 8.43 (3, J 8.0 Hz), and 8.09 (d, J 8.0 Hz) together (1H, CONH), 6.98 (2H, t, J 7.6, ArH), 6.64 (2H, d, J 7.3, ArH), 4.81-4.67 (m), 4.47 (d, J 8.7 Hz) and 4.35-4.21 (m), together (4H, CHα-tyr, CHαthiopro and NCH2S), 3.32 (dd, J 7.2, 11.6 Hz), 3.17 (dd, J 7.5, 11.6 Hz), 2.99-2.72 (m) together (4H, CH2Ar+CHCH2S), 2.06 (s) and 1.84 (s) together (3H, CH3CO) and 1.36 (9H, S, CO2tBu); m/z (ESI, 15V) 395 (M+ +1).

Provenance & Evidence