Cesium carbonate → Methyl N-(tert-butoxycarbonyl)-4-(2-methylphenyl)-5-oxonorleucinate

To a solution of methyl N-(tert-butoxycarbonyl)-3-iodo-D-alaninate (1.58 g, 4.80 mmol) in DMF (24 mL) was added cesium carbonate (1.56 g, 4.80 mmol) and the mixture was stirred at 23° C. for 45 min. 1-(2-Methylphenyl)-propan-2-one (0.783 g, 5.28 mmol) and cesium carbonate (2.35 g, 7.20 mmol) were added and the resulting mixture was stirred for 18 h. The mixture was filtered and water was added to the filtrate. The mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with water (3×), brine, dried over sodium sulfate, filtered and concentrated. Purification by silica gel chromatography (5% ethyl acetate→40% ethyl acetate/hexane) gave the title compound. MS: m/z=350.1 (M+1).

1. stirringthe resulting mixture was stirred for 18 h
2. filtrationThe mixture was filtered
3. additionwater was added to the filtrate
4. extractionThe mixture was extracted with ethyl acetate (3×)
5. washThe combined organic extracts were washed with water (3×), brine
6. dry with materialdried over sodium sulfate
7. filtrationfiltered
8. concentrationconcentrated
9. customPurification by silica gel chromatography (5% ethyl acetate→40% ethyl acetate/hexane)

ORD-Eintrag

ord-a0f47b80167a4c949cf380d85d522055

Quelldatensatz

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08912210B2