Water → HCID 11099982, compound

Participants

Reaction Steps

To a stirred solution of Z-Tyr-OH (63.24 g, 200 mmol) in THF (900 ml) at 0° C. was added finely powdered KOH (112.72 g, 2 mol) in portions, followed by the addition of tetrabutylammonium hydrogen sulfate (6.36 g, 10% by weight). Then, dimethyl sulfate (127.2 ml, 1.33 mol) was added dropwise over 30 min, while maintaining the reaction mixture below 4° C. The reaction was stirred for an additional 30 min and H2O (950 ml) was added. After stirring 5 h at 0° C., the reaction was diluted with ether (1500 ml), the aqueous layer was separated, and the organic layer was extracted with aq NaHCO3 (2×500 ml, sat). The combined aqueous layers were acidified to pH 1 with aq 1M KHSO4, and extracted with EtOAc (5×500 ml). The organic layers were combined, dried (Na2SO4), filtered and concentrated. The residue was precipitated with ethyl ether and filtered to give E1 as a white solid (53.85 g, 78%).

Provenance & Evidence