Acetic Acid → 1-Benzyl-4-[N-ethyl-N-(6-fluoro-3-(isopropylamino)-2-pyridinyl)amino]piperidine

Participants

Reaction Steps

1-Benzyl-4-[N-ethyl-N-(6-fluoro-3-(nitro)-2-pyridinyl)amino]piperidine (EXAMPLE 195, 3.0 g, 8.37 mmol) is dissolved in ethanol (500 ml) and 0.75 g of platinum oxide is added. The reaction is placed on a Parr hydrogenator at 10 psi for 1 hr and then filtered through diatomaceous earth and concentrated under reduced pressure. The crude 1-benzyl-4-[N-ethyl-N-(6-fluoro-3-(amino)-2-pyridinyl)amino]piperidine (3.0 g, 9.13 mmol) is immediately dissolved in methanol (18 ml) and acetone (0.74 ml, 10.04 mmol) and acetic acid (13.1 ml, 228.3 mmol) are added. The reaction is stirred for 10 min, then cooled to 0° and sodium cyanoborohydride (0.61 g, 9.7 mmol) is added. The reaction is slowly warmed to 20°-25° and stirred for 18 hr. Then solid sodium bicarbonate is added with caution and the reaction is extracted with chloroform, washed with saline, dried over sodium sulfate and concentrated under reduced pressure. Purification via flash column chromatography (5% ethyl acetate/hexane to 10% ethyl acetate/hexane) gives the title compound, NMR (300 MHz, CDCl3) 7.26-7.15, 6.88, 6.49, 4.28, 3.40, 3.44, 3.04, 2.93, 2.82, 1.93, 1.72-1.52, 1.13 and 0.81δ; CMR (CDCl3, 75 MHz) 155.9, 152.5, 146.1, 138.0, 129.1, 128.1, 126.9, 121.8, 104.3, 62.9, 57.5, 52.7, 44.4, 41.2, 29.7 and 22.8δ.

Provenance & Evidence