To a flask containing a solution of 29, Et3N (0.26 g, 2.55 mmol) and DMAP (0.032, 0.26 mmol) in CH2Cl2 (5 mL) was added methanesulfonyl chloride (0.24 g, 2.13 mmol), dropwise at RT and the reaction allowed to stir overnight. After 18 h the reaction was diluted with CH2Cl2 (15 mL) and the reaction rinsed with 10% aqueous HCl (25 mL). The CH2Cl2 layer was dried (MgSO4) and concentrated to a dark amber oil. The crude product was purified by silica gel column chromatography to afford 170 mg (46%) of the title compound (269) as a colorless oil. An additional 90 mg of a mixture of 269 and N,N-bissulfonylated product was also isolated. 1H NMR (400 MHz, DMSO-d6): δ 2.15 (s, 3H), 2.82 (s, 3H), 3.85 (s, 3H), 6.54 (d, J=8.9 Hz, 2H), 6.94 (d, J=8.8 Hz, 2H), 6.97 (dd, J1=2.4 Hz, J2=9.1 Hz, 1H), 6.96 (d, J=6.6 Hz, 1H), 7.15-7.32 (m, 5H), 7.58 (d, J=9.1 Hz, 1H), 7.67 (s, 1H), 9.32 (s, 1H).
