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

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Reaction Steps

Boc-Ala-Pro-OBzl (75.3 g, 0.2 mole) was deprotected by stirring for 1.5 h. in 4.2N 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 min, 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 faltered, washed with petroleum ether, and dried to obtain 76.2 g (yield 87.88%) of II. Rf1 0.39; Rf2, 0.44.

Provenance & Evidence