9-Fluorenylmethyl chloroformate → 2-(2,2-Dimethoxy-ethyl)-6-(4-phenyl-butylcarbamoyl)-piperidine-1-carboxylic Acid 9H-fluoren-9-ylmethyl Ester

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Reaction Steps

2-(2,2-Dimethoxy-ethyl)-6-(4-phenyl-butylcarbamoyl)-piperidine-1-carboxylic acid benzyl ester (Compound 242, 0.887 g, 1.83 mmol) was dissolved in methanol (50 mL). Palladium (10%) on activated carbon (0.09 g) was added. Hydrogen was applied via Parr apparatus, and the reaction was shaken at 50 psi for 15 hours. The black suspension was then filtered through compacted Celite, and methanol was removed. The residue was dissolved in dioxane (25 mL). 9-Fluorenylmethyl chloroformate (0.473 g, 1.83 mmol) was added, followed by NaHCO3 (0.307 g, 3.66 mmol) dissolved in water (7 mL). The reaction was stirred at room temperature for 10 hours, poured into ice and 5% KHSO4 solution, and then extracted with CHCl3 (2×100 mL). Flash chromatographic purification of the residue (1:2 EtOAc/hexanes) gave Compound 243 (1.050 g, 100%). Rf=0.59 (1:1 EtOAc/hexanes).

Provenance & Evidence