反应详情

A solution of 18.27 g (68.9 mmol) of methyl 3-benzyloxycarbonylamino-3-methylbutanoate (Step D) in 20 mL of methanol at room temperature was treated dropwise wit 51 mL of 2N NaOH (102 mmol, 1.5 eq). The mixture was stirred at room temperature for 16 hours then transferred to a separatory funnel and washed with hexane (3×). The aqueous layer was removed, cooled to 0° and slowly acidified to pH 2 (paper) by dropwise addition of 6N HCl. This mixture was extracted with ether (6×); combined extracts were washed with 1N HCl and brine, then dried over magnesium sulfate, filtered and solvent removed under vacuum to afford 17.26 g (68.7 mmol, 99%) of the product. 1H NMR (200 MHz,CDCl3): 1.42 (s,6 H), 2.77 (s,2 H), 5.06 (s,2 H), 5.2 (br s,1 H), 7.3 (s,5 H).

1. customthen transferred to a separatory funnel
2. washwashed with hexane (3×)
3. customThe aqueous layer was removed
4. temperaturecooled to 0°
5. additionslowly acidified to pH 2 (paper) by dropwise addition of 6N HCl
6. extractionThis mixture was extracted with ether (6×)
7. washcombined extracts were washed with 1N HCl and brine
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. customsolvent removed under vacuum