synthesis of 4-(Methylsulfonyl)phenylacetic acid: 1-(4-Methanesulfonyl-phenyl)-ethanone (20 mmol), morpholine (60 mmol) and elemental sulfur (40 mmol) were added in a round-bottom flask and refluxed for 2 h at 398 K. A 3N solution of NaOH (20 ml) was then added, and the reaction mixture refluxed for an additional 30 min. After cooling, the mixture was filtered and the filtrate was acidified with HCl to pH 6. The solution was again filtered off and washed with ethyl acetate. The resulting aqueous fraction was finally acidified with diluted HCl, to yield the pure product as a white solid. Crystals suitable for X-ray analysis were obtained by slow evaporation of an ethanol/water (1:1 v/v) solution.
