Into a 50 mL single neck flask, 1 mL oxalyl chloride was added syringe wise to (+)-4-[4-(1-fluoro-1-methyl-2-{[(methylethyl)sulfonyl]amino}ethyl)phenyl]benzoic acid (300 mg, 0.79 mmol, prepared in example 1a) in CH2Cl2 (20 mL) while stirring under nitrogen at room temperature. Immediately, 1 drop of DMF was added by pipette initiating a foaming of the mixture. The reaction was stirred one hour at this temperature and then concentrated under reduced vacuum to yield a white semi-solid. This material was placed into dioxane (20 mL) and added dropwise to a stirring solution of 40% methylamine (5 mL) at room temperature and the mixture was stirred overnight. In the morning, the solution was concentrated under reduced vacuum and the resulting oil was taken into methylene chloride and the organic layer was washed once with H2O, dried over K2CO3, filtered, and concentrated under reduced vacuum to yield 271 mg as a semi-solid. This material was purified via silica gel chromatography employing the Chromatotron and using a 2000 micron rotor while eluting with a solvent of methylene chloride/ethyl acetate 1:1 to yield the title compound (100 mg, 32%) as a white solid. Ion spray M.S. 391.2 (M*−1).
