Diethyl azodicarboxylate → 4-[3-(4-Ethoxycarbonyl-2-fluoro-phenoxy)-propyl]-piperazine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Triphenylphosphine polystyrene (loading 1.0 mmol/g, 11 g, 11.0 mmol) and DEAD (2.45 g, 11.0 mmol) were added to a solution of 3-fluoro-4-hydroxy-benzoic acid ethyl ester from Example E27 (1.3 g, 7.4 mmol) and 4-(3-hydroxy-propyl)-piperazine-1-carboxylic acid tert-butyl ester from Example E34 (1.8 g, 7.4 mmol) in tetrahydrofuran (100 ml) at 0° C. The suspension was allowed to warm to room temperature and stirred for 18 h. The mixture was filtered and the filtrate concentrated in vacuo. The residue was purified by flash chromatography on silica gel (eluant; EtOAC) to yield the title compound (1.7 g, 57%).

Provenance & Evidence