4-Methylmorpholine → HCID 53656047, compound

Participants

Reaction Steps

Z-Asp(OtBu)-Ala-OBzl (43,6 g, 90 mmol) was dissolved 1 liter DMF and hydrogenated in the presence of Tos-OH.H2O (17,1 g, 90 mmol) and 10% Pd-C. After the hydrogenation was completed the catalyst was filtered off. The filtrate was cooled to 0°, neutralized with N-methylmorpholine (9,9 ml, 90 mmol) and added to Z-Ser(tBu)-OSu. Another portion of N-methylmorpholine (9,9 ml, 90 mmol) was added and the reaction mixture was stirred at 0° for 1 h and at 25° for 18 h. 2-Diethylamino-ethylamine (2,83 ml, 20 mmol) was added to the reaction mixture and stirring was continued for 4 h. The solution was evaporated in vacuo, the residue dissolved in 0,5N NaOH (0,5 l) and extracted with ether (3×0,2 l). To the alkaline phase 0,4 l ethyl acetate was added and acidified with 5% KHSO4 /10% K2SO4 -solution. The acidic layer was again extracted with ethyl acetate (2×0,3 l). The combined organic layers were washed with 5% KHSO4 /10% K2SO4 -sol. (1×0,3 l) and saturated NaCl-sol., dried over Na2SO4, filtered and evaporated in vacuo.

Provenance & Evidence