Water → tert-Butyl 4-(3-ethoxy-3-oxopropanoyl)piperidine-1-carboxylate

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Reaction Conditions

Reaction Steps

Piperidine-1,4-dicarboxylic acid 1-tert-butyl ester 4-ethyl ester (0.50 g, 1.94 mmol) in DMF (5 mL) was mixed with ethyl acetate (0.38 mL, 3.88 mmol) and potassium tert-butoxide (0.33 g, 2.92 mmol). The mixture was heated to 50° C. for 20 hours. After cooling to room temperature, water was added (50 mL) and the product was extracted with diethyl ether. The ether extract was dried over sodium sulfate, filtered and concentrated. The crude product was purified by column chromatography on silica gel, eluting with heptane-ethyl acetate to provide 4-(2-ethoxycarbonylacetyl)-piperidine-1-carboxylic acid tert-butyl ester (0.27 g, 47% yield). 1H NMR (300 MHz, CDCl3/TMS): δ=4.20 (q, 2H, J=7.2 Hz), 4.18-4.05 (m, 2H), 3.50 (s, 2H), 2.86-2.70 (m, 2H), 2.68-2.55 (m, 1H), 1.90-1.78 (m, 2H), 1.60-1.50 (m, 2H), 1.45 (s, 9H), 1.28 (t, 3H, J=7.2 Hz). 13C NMR (75 MHz, CDCl3/TMS): 6=204.21, 167.20, 154.67, 79.91, 61.70, 48.93, 47.56, 43.41, 28.73, 27.56, 14.46.

Provenance & Evidence