Diisopropylethylamine → tert-Butyl 4-{4-[ethyl(1-methyl-2-oxo-2-phenylethyl)carbamoyl]thiazol-2-yl}-piperidine-1-carboxylate

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Reaction Steps

tert-Butyl 4-(4-carboxythiazol-2-yl)piperidine-1-carboxylate (6.5 mmol; 2.03 g) is dissolved in 40 ml of anhydrous dimethylformamide and placed under an inert atmosphere, and 2-(ethylamino)propiophenone hydrochloride (1 eq.; 6.5 mmol; 1.39 g), HBTU (1 eq.; 6.5 mmol; 2.47 g) and N-ethyldiisopropylamine (3.5 eq.; 22.75 mmol; 3.97 ml) are then added. The reaction medium is stirred at room temperature overnight. The reaction medium is evaporated to dryness and then taken up in dichloromethane and washed with saturated potassium carbonate (K2CO3) solution, citric acid solution and water (twice). The organic phase is dried over sodium sulfate and then evaporated to dryness. The crude product is chromatographed on silica, using a 1/1 ethyl acetate/hexane mixture as eluent (Rf=0.55) to give 2.6 g of expected product in the form of an oil.

Provenance & Evidence