Phosphorus oxychloride → 2-Chloro-4-((1R,2S)-2-hydroxy-1-(5-phenyloxazol-2-yl)propylamino)-3-methylbenzonitrile

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Reaction Steps

A 100 mL round bottomed flask was charged with phosphorous oxychloride (0.5 mL, 5.24 mmol) and benzene (20 mL). (2R,3S)-3-(tert-butyldimethylsilyloxy)-2-(3-chloro-4-cyano-2-methylphenylamino)-N-(2-oxo-2-phenylethyl)butanamide (1.14 g, 2.28 mmol) was then added to the mixture which was then placed under reflux for 4 h. The mixture was then concentrated en vacuo, then partitioned between EtOAc (40 mL) and a saturated solution of sodium bicarbonate (30 mL). The organic layer was washed with water (20 mL), dried (Na2SO4). Purification by flash column chromatography [hexanes/Et2O (3:2) as eluent] afforded the title compound as a white solid (30 mg, 4% yield). 1H NMR (500 MHz, CDCl3, δ in ppm) 7.59 (d, J=8 Hz, 2H), 7.32-7.42 (m, 4H), 7.28 (s, 1H), 6.58 (d, J=8 Hz, 1H), 5.17 (d, J=7 Hz, 1H), 4.93-4.95 (m, 1H), 4.66-4.75 (m, 1H), 2.40 (s, 3H) and 1.63 (d, J=6 Hz, 3H).

Provenance & Evidence