Example 1
To a solution of the SM (3.0 g, 19.46 mmol) in H2SO4 (20 mL) at 0 C was added dropwise HNO3 (0.913 mL, 20.44 mmol). The reaction was stirred at 0 C for 1 h. The mixture was poured onto ice and extracted with DCM (2x). The combined organics were washed with brine, dried (MgSO4), and concentrated to provide the product. [3.48 g, 90%]
[Patent Reference: WO2013134298, page 35, (4.1 MB)]
Example 2
To a mixture of the SM (30.0 g, 159 mmol) and concentrated H2SO4 (100 mL) at about -5 C was added dropwise HNO3 (11.0 mL, 174 mmol) over 20 min. The reaction mixture was allowed to warm to RT and stir for 30 min. The mixture was poured onto crushed ice with stirring and partitioned with MTBE (200 mL). The layers were separated and the aq layer was further extracted with MTBE (2 x 50 mL). The combined organics were dried and concentrated in vacuo to provide the product as an orange-colored viscous oil. [39.0 g]
[Patent Reference: WO2013134298, page 42, (4.1 MB)]