反应详情

HOBt (3 equivalents, 39.4 g, 292 mmol), N-methylmorpholine (3 equivalents, 32.1 ml, 291.8 mmol), N-tert-butoxycarbonyl-3-tert-butyl-D-alanine (Example 6A, 1.0 equivalent, 97.3 mmol), EDC (2 equivalents, 37.3 g, 194.6 mmol) and again N-methylmorpholine (2 equivalents, 21.4 ml, 194.5 mmol) are added successively at −20° C. to a solution of 3-tert-butyl-L-alanine methyl ester hydrochloride (1.1 equivalents, 21 g, 107 mmol) in dichloromethane p.a. (1.4 l). The reaction mixture warms slowly (about 12 h) to RT, whereby complete conversion of the amine component is observed by means of HPLC. The reaction mixture is then washed with a saturated aqueous sodium hydrogen carbonate solution (300 ml), 5% aqueous citric acid (2×500 ml), a saturated aqueous sodium hydrogen carbonate solution (500 ml) and a saturated sodium chloride solution. The reaction mixture is dried over sodium sulfate and filtered. The mixture is concentrated to dryness in vacuo and then dried further under high vacuum. 36 g (96% of theory) of the title compound are obtained, which is reacted without further purification.

1. customThe reaction mixture warms slowly (about 12 h)
2. customto RT
3. washThe reaction mixture is then washed with a saturated aqueous sodium hydrogen carbonate solution (300 ml), 5% aqueous citric acid (2×500 ml)
4. dry with materialThe reaction mixture is dried over sodium sulfate
5. filtrationfiltered
6. concentrationThe mixture is concentrated to dryness in vacuo
7. customdried further under high vacuum