Hydrochloric Acid → p-Toluenesulfonic acid

Participants

Reaction Steps

To 15 mL of methanol, 1.30 g (prepared to be 6.87 mmol) of the hydrochloric acid salt and 1.36 g (7.15 mmol, 1.04 eq) of p-toluenesulfonic acid monohydrate were added, and dissolving under heating was made at 40 to 50° C., followed by making concentration of almost whole methanol (about 13 mL) under reduced. The precipitated crystal was filtered, and washed with a small amount of n-heptane, followed by being subjected to drying under vacuum, thereby obtaining 960 mg of p-toluenesulfonic acid salt (refined product) of α-trifluoromethyl-β-substituted-β-amino acids represented by the above-mentioned formula. The total yield from α-trifluoromethyl-β-substituted-α,β-unsaturated esters was 41%. The diastereomer ratio was syn-body:anti-body=>98:2 according to 1H- and 19F-NMR analyses.

Provenance & Evidence