4-Methylmorpholine → Boc-Gly-Ala-Pro-OBzl

Participants

Reaction Steps

Boc-Ala-Pro-OBzl (75.3 g, 0.2 mole) was deprotected by stirring for 1.5 h. in 4.2 N HCl in dioxane. Excess HCl and dioxane were removed under reduced pressure, triturated with ether, faltered, washed with ether, and dried (yield 100%). A solution of Boc-Gly-OH (35.04 g, 0.2 mole) and HOBt (27.02 g, 0.2 mole) in DMF was cooled to -15° C. with stirring and EDCI (38.34 g, 0.2 mole) was added. After 20 rain, a pre-cooled solution containing the above hydrochloride salt and NMM (21.98 mL, 0.2 mole) was added and the reaction mixture was stirred overnight at room temperature. The mixture was evaporated to a thick oil which was dissolved in CHCl3. This solution was extracted with water, 10% citric acid, water, 5 % NaHCO3, water, and dried over Na2SO4. The solvent was removed under reduced pressure and the resulting oil was crystallized from ether/petroleum ether. The solid was filtered, washed with petroleum ether, and dried to obtain 76.2 g (yield 87.88%) of II. R1f 0.39; R2f, 0.44.

Provenance & Evidence