p-Toluenesulfonic acid monohydrate → Methyl 4-cyano-2-fluorobenzoate

Participants

Reaction Steps

A solution of 4-cyano-2-fluorobenzoic acid (4.02 g, 24.36 mmol, Aldrich) in methanol (50 mL) was treated with p-toluenesulfonic acid monohydrate (0.46 g, 2.43 mmol) and heated to reflux overnight. The solvent was removed and the reaction residue was extracted with EtOAc, washed with saturated Na2CO3, brine and dried over Na2SO4 to give Methyl 4-cyano-2-fluorobenzoate (4.46 g, 95%). This Methyl ester (1.03 g, 5.77 mmol) was combined with methanol (60 mL) and Raney Ni (2 spatula tip fulls were added after washing with methanol under argon). It was then put under Hydrogen at 50 PSI on a PARR shaker for 18 hrs. The reaction was filtered through celite and washed with methanol while being kept under N2. It was then purified by silica gel chromatography with methanol and methylene chloride to give methyl 4-(aminomethyl)-2-fluorobenzoate (247.6 mg, 23%) as off-white solid.

Provenance & Evidence