Compound 197 (0.173 g, 0.315 mmol) was dissolved in 10 mL of DCM and to this was added 4N HCl in dioxane (1.97 mL, 7.88 mmol). The solution was stirred at room temperature overnight and then concentrated under vacuum to give a yellow solid. The solid obtained was sonicated in Et2O and a yellowish solid was collected on filter paper to give compound 190 as an HCl salt (0.164 g, 100%). 1H NMR (500 MHz, DMSO-d6) δ 10.56 (1 H, br. s.), 9.42 (1 H, s), 8.87 (2 H, br. s.), 8.28 (1 H, d, J=4.9 Hz), 8.19 (1 H, d, J=5.1 Hz), 8.09 (1 H, d, J=2.9 Hz), 7.97 (1 H, d, J=9.0 Hz), 7.75 (1 H, dd, J=9.3, 2.0 Hz), 5.96-6.07 (2 H, m, J=9.2, 8.9, 8.8, 8.8 Hz), 3.37-3.43 (4 H, m), 3.26-3.33 (4 H, m), 2.54-2.65 (2 H, m), 2.01-2.12 (4 H, m), 1.66-1.77 (2 H, m) ppm; LCMS-ESI (POS), M/Z, M+1: Found 449.2.
