Step 2: To a solution of compound [63] (22.8 g, 2.4 mmol, 1 eq.) in anhydrous ethanol (100 mL), NaOH granules (9.55 g, 238 mmol, 1 eq.) were added and the reaction mixture was stirred for 16 h at room temperature. Subsequently, a solution of compound [84] was slowly added through a dropping funnel over a period of 2 hours. After addition, the reaction mixture was continued to be stirred for 2 hours. Upon completion of the reaction, the solvent was removed by evaporation and the residue was dissolved in water (500 mL) with vigorous stirring for 2 hours, followed by standing at room temperature overnight. The precipitate precipitated was collected by filtration and dried under vacuum to give compound [85] as a light yellow solid (20.6 g, 53% yield).
