A solution of 124C (7.0 g, 32.4 mmol) in concentrate H2SO4 (9.5 mL) was added to a solution of concentrate H2SO4 (9.5 mL) and fuming HNO3 (13 mL) and the mixture was heated at 60°C for 30 min. After cooling to room temperature, the reaction mixture was added to iced 6M solution of NaOH (150 mL) and neutralized to pH 6 with 1N NaOH solution. The reaction mixture was extracted with dichloromethane (4x100 mL). The combined organic phases were dried over Na2SO4, filtered and concentrated to give 124D as a solid.