Sodium cyanoborohydride → 2,3-Dichloro-N-{2-[formyl(Hydroxy)amino]ethyl}benzamide

関与物質

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To a solution of 2,3-dichloro-N-(2-hydroxyimino-ethyl)-benzamide (34.3 g, 0.14 mol) in MeOH (700 mL) under an argon atmosphere at 0° C. was added methyl orange (0.01 g) followed by a saturated solution of MeOH/HCl until a persistent red color was observed. Sodium cyanoborohydride (10.5 g, 0.17 mol) was added sequentially with saturated MeOH/HCl over 0.5 h. The reaction mixture was stirred an additional 1 h and the MeOH was removed in vacuo. The residue was partitioned between 3N HCl (300 mL) and dichloromethane (300 mL). The organic phase was extracted with 3N HCl (2×200 mL). The combined aqueous extracts were washed with dichloromethane, were basidified with cold dilute NaOH and were extracted (7×100 mL) with dichloromethane/MeOH (9:1). The combined organic extracts were washed with brine, were dried (Na2SO4) and were concentrated. The residue was diluted with ether (200 mL) and the precipitate collected by filtration to provide the title compound (11 g, 32%) as a white solid. 1H NMR (400 MHz, CD3OD): δ 7.60 (dd, j=1.7 and 7.8 Hz, 1H); 7.41 (dd, j=1.7 and 7.6 Hz, 1H); 7.35 (t, j=7.7 Hz, 1H); 3.57 (t, j=6.2 Hz, 2H); 3.06 (t, j=6.2 Hz, 1H).

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