反应详情

Lithium hydroxide monohydrate (0.455 g, 10.84 mmol) was added to a solution of (S)-methyl 3-(1-(2-(tert-butoxy)-2-oxoethyl)-1H-indol-3-yl)-2-((tert-butoxycarbonyl)amino)propanoate (4.69 g, 10.84 mmol) in dioxane (50 mL) and water (16.67 mL) and stirred at RT for 1 hr. The reaction was neutralized with 1M HCl and extracted with EtOAc. The organic layer washed with brine, collected, dried over MgSO4, filtered and evaporated to give the crude material. The crude material was purified via silica gel chromatography (120 g column, 0-50% EtOAc:Hex over 20 CV) to get the product (S)-3-(1-(2-(tert-butoxy)-2-oxoethyl)-1H-indol-3-yl)-2-((tert-butoxycarbonyl)amino)propanoic acid (3.54 g, 78% yield). 1H NMR (400 MHz, chloroform-d) d 7.62 (d, J=7.8 Hz, 1H), 7.26-7.21 (m, 2H), 7.15 (ddd, J=7.9, 5.6, 2.3 Hz, 1H), 6.99 (s, 1H), 5.08 (d, J=7.8 Hz, 1H), 4.71 (s, 2H), 4.65 (br. s., 1H), 3.42-3.31 (m, 2H), 1.46 (s, 18H). ESI-MS(+) m/z=441 (M+Na).

1. extractionextracted with EtOAc
2. washThe organic layer washed with brine
3. customcollected
4. dry with materialdried over MgSO4
5. filtrationfiltered
6. customevaporated
7. customto give the crude material
8. customThe crude material was purified via silica gel chromatography (120 g column, 0-50% EtOAc:Hex over 20 CV)