Sulfuric Acid → Methyl-trans-1-[bis(4-methoxyphenyl)methyl]-6-oxo-4-(2,4,5-trifluorophenyl)piperidine-3-carboxylate

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Reaction Steps

To a stirred solution of 6.6 g (23 mmol) of the product of Step C in 100 mL of acetic acid was added 6.11 g (25 mmol) of 4,4′-dimethoxybenzhydrol followed by 5 mL of concentrated sulfuric acid and the resulting solution was stirred at ambient temperature for 18 h. The solution was then concentrated and cooled 0° C. before quenching with ice water (100 mL). The resulting mixture was extracted with three 300-mL portions of ethyl acetate, and the organic phases combined and washed sequentially with water, saturated aqueous sodium bicarbonate solution, and saturated aqueous brine (200 mL each). The organic phase was dried over magnesium sulfate, filtered, and evaporated in vacuo to yield a viscous oil. The crude material was purified by flash chromatography on a Biotage Horizon® system (silica gel, 0 to 50% ethyl acetate/hexanes gradient) to give methyl-trans-1-[bis(4-methoxyphenyl)methyl]-6-oxo-4-(2,4,5-trifluorophenyl)piperidine-3-carboxylate as a colorless solid. LC/MS 536.2 (M+23).

Provenance & Evidence