反应详情

A solution of 18.3 g (68.9 mmol) of methyl 3-benzyloxycarbonylamino-3-methylbutanoate (Step B) in 20 mL of methanol at room temperature was treated dropwise with 51 mL of 2 N 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 6 N HCl. This mixture was extracted with ether (6×); combined extracts were washed with 1 N HCl and brine, then dried over magnesium sulfate, filtered and solvent removed under vacuum to afford 17.3 g (68.7 mmol, 99%) of the product. 1H NMR (200 MHz, CDCl3): δ 1.42 (s, 6H), 2.77 (s, 2H), 5.06 (s, 2H), 5.2 (br s, 1H), 7.3 (s, 5H).

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 6 N HCl
6. extractionThis mixture was extracted with ether (6×)
7. washcombined extracts were washed with 1 N HCl and brine
8. dry with materialdried over magnesium sulfate
9. filtrationfiltered
10. customsolvent removed under vacuum