Methanol → Methyl (3S)-4-{[(1,1-dimethylethyl)(diphenyl)silyl]oxy}-3-({[(phenylmethyl)oxy]carbonyl}amino)butanoate

Beteiligte Stoffe

Reaktionsschritte

In a 1000 ml round-bottomed flask (3S)-4-{[(1,1-dimethylethyl)(diphenyl)silyl]oxy}-3-({[(phenylmethyl)oxy]carbonyl}amino)butanoic acid D2 (15 g) was dissolved in DMF (200 ml). To this solution DIPEA (28.8 ml, 165 mmol) and TBTU (11.46 g, 35.7 mmol) were added and the solution left under stirring at room temperature for 20 minutes. After this time to the brown solution MeOH (11 ml) was added and the mixture left under stirring at room temperature for 30 minutes. The reaction mixture was transferred into a separatory funnel containing brine (600 ml) and extracted with EtOAc (5×200 ml). The organic phases were washed with water (3×100 ml), dried (Na2SO4) and evaporated under vacuum to give an orange oil. This material was purified by column chromatography on silica gel (flash master, Cy/EtOAc from 100/0 to 80/20) to give the title compound D3 (13.9 g) as a yellow solid. MS: (ES/+) m/z: 506 (M+1). C29H35NO5Si requires 505. 1H NMR (400 MHz, CDCl3-d6) δ (ppm): 7.69-7.29 (m, 15 H), 5.4-5.26 (m, 1 H), 5.11 (m, 2 H), 4.25-4.14 (m, 1 H), 3.82-3.68 (m, 2H), 3.64 (s, 3 H), 2.79-2.52 (m, 2 H), 1.08 (s, 9 H).

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