TfOH-TFA → 5-Chloro-pyridine-2-sulfonic acid ((R)-5,5-difluoro-2-oxo-azepan-3-yl)-amide

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Reaction Steps

A mixture containing trifluoroacetic acid/trifluoromethanesulfonic acid (5:2 v/v, 2.44 ml) was added to 5-chloro-pyridine-2-sulfonic acid [(R)-1-(2,4-dimethoxy-benzyl)-5,5-difluoro-2-oxo-azepan-3-yl]-amide (0.37 g, 0.76 mmol) in dichloromethane (20 ml). After 2 h the reaction mixture was concentrated under reduced pressure and the residue taken up in ethyl acetate and washed with water, saturated aqueous sodium bicarbonate and brine, dried (Na2SO4), filtered, concentrated under reduced pressure and purified over silica gel (heptane-ethylacetate, 1:1-0:1); white solid 0.22 g (84%); MS: m/e=340.0 (MH+).

Provenance & Evidence