Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → 3-(5,6,7,8-Tetrahydro-[1,8]naphthyridin-2-yl)-acrylic acid ethyl ester

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Reaction Steps

A solution of 5,6,7,8-tetrahydro-[1,8]naphthyridine-2-carbaldehyde (4-7, 2 g, 12.34 mmol) and (carbethoxymethylene)triphenylphosphorane (4.3 g, 12.34 mmol) in toluene (60 mL) was heated to reflux for 4 hours and stirred at ambient temperature for 12 hours. Following evaporative removal of the solvent, the residue was chromatographed (silica gel, 50% EtOAc/hexanes) to give 4-8 as a yellow solid.

Provenance & Evidence