Yield: 7%

Spectra NMR <sup>1</sup>H (400 MHz, DMSO-d6, δ, ppm, *J*/Hz): 3.22 (2H, *t*, *J* = 6.07 Hz, H-5), 3.73 (3H, s, SCH3), 4.12 (3H, s, OCH3), 5.00 (2H, *t*, *J* = 5.72 Hz, H-6), 6.19 (2H, s, OCH2O), 7.11 (1H, s, H-4), 7.82 (1H, s, H-1), 8.27 (1H, *d*, *J* = 9.06 Hz, H-12), 8.34 (1H, *d*, *J* = 9.06 Hz, H-11), 9.08 (1H, s, H-13), 9.72 (1H, s, H-8). Spectra NMR <sup>13</sup>C (100 MHz, DMSO-d6, δ, ppm): 26.18 (C-5), 40.02 (SO2*CH3*), 55.70 (C-6), 57.44 (OCH3), 102.23 (OCH2O), 105.60 (C-1), 108.49 (C-4), 120.20 (C-13b), 120.86 (C-13), 121.79 (C-8a), 126.47 (C-12), 128.03 (C-11), 131.05 (C-4a), 131.44 (C-12a), 133.31 (C-13a), 138.59 (C-9), 144.04 (C-8), 147.77 (C-2), 150.17 (C-3), 151.89 (C-10). Spectra IR (cm−<sup>1</sup> ): 804.21, 925.71, 1033.71, 1097.35, 1224.63, 1263.20, 1365.42, 1506.20, 1610.34, 1623.84, 3039.40, 3320.97, 3635.33. MS (ESI): m/z (M+) calcd for C20H18NO6S +, 400.085 found: 400.081.

3.1.4. 9-Ethanesulfonyloxy-10-methoxy-2,3-methylenedioxyprotoberberine chloride (**10b**)
