Ammonium Chloride → N-(1-ethyl-3-fluoro-1,2,5,6-tetrahydro-pyridin-4-yl)benzamide

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Reaktionsschritte

A solution of 4-benzamido-1-ethyl-3-fluoro-pyridinium iodide (6.45 kg, 17.3 mol) in methanol (40 L) was charged with sodium borohydride (1.82 kg, 43.3 mol) via portion-wise addition over five to six hours maintaining an internal reaction temperature between −5° C. and 10° C. Following this addition saturated aqueous ammonium chloride (10 L) was added and the reaction mixture stirred for 1 h, and then saturated aqueous sodium bicarbonate (12 L) was added and the mixture was left to stand overnight. Methanol was removed under vacuum and the resulting aqueous solution was extracted with ethyl acetate (3×30 L), washed with water, brine and dried over sodium sulfate. The concentrated organic layer yielded 3.36 kg of N-(1-ethyl-3-fluoro-1,2,5,6-tetrahydro-pyridin-4-yl)benzamide (78%). 1H NMR (400 MHz, CDCl3) δ 7.78 (2H, d, J=7.7 Hz), 7.48 (4H, dq, J=14.9, 7.4 Hz), 3.17 (2H, s), 2.89 (2H, s), 2.65 (2H, t, J=5.6 Hz), 2.55 (2H, q, J=7.1 Hz), 1.13 (3H t, J=7.2 Hz).

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