1,4-Dioxa-8-azaspiro(4.5)decane → 1-(5-Cyano-2-methoxyphenyl)-4-piperidone ethylene ketal

참여 물질

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1,4-Dioxa-8-azaspiro[4.5]decane (1.47 g, 10.28 mmol), sodium bis(trimethylsilyl)amide (1 N in THF, 12 ml), and PdCl2(p(o-tolyl)3)2 [2 mol % catalyst prepared from bis(acetonitrile) Pd(II) chloride(53 mg, 0.206 mmol) and tri(o-tolyl)phosphine (125 mg, 0.52 mmol)] were added to a solution of 3-bromo-4-methoxybenzonitrile (1.82 g, 8.58 mmol) in toluene (40 ml). The reaction was stirred for 5 hours at 100° C. The reaction was concentrated in vacuo, diluted with water, and extracted with methylene chloride. The organic extract was concentrated in vacuo, and the residue purified by chromatography on silica gel using hexane/ethyl acetate (80/20) as the eluent to give 1-(5-cyano-2-methoxyphenyl)-4-piperidone ethylene ketal (900 mg, 38%). This ketal was dissolved in dioxane (15 ml) and HCl (6 N, 2.2 ml) and stirred at 100° C. for 2 h. The solution was cooled, quenched with saturated aqueous NaHCO3. The mixture was extracted with methylene chloride, concentrated in vacuo, and purified by chromatography on silica gel using hexane/ethyl acetate (80/20) as the eluent to give 1-(5-cyano-2-methoxyphenyl)-4-piperidone (125 mg, 19%).

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