In a 100 mL round bottom flask, 4 (0.50 g, 0.91 mmol) and 25% w/v NaOMe/MeOH (0.70 mL, 2.64 mmol) were combined and dissolved in 50 mL ACN. The solution was heated under reflux for 24 h, after which the ACN was removed under reduced pressure. The product was then redissolved in DCM and washed with aliquots (3 × 50 mL) of a 5% aq. Na2CO3 solution. The organic later was dried with anhydrous MgSO4, filtered, and the DCM removed under reduced pressure.