To a solution of EXAMPLE 1C (10.00 g, 23.4 mmol) in tetrahydrofuran/methanol (100/50 mL) was added solution of lithium hydroxide monohydrate (2.59 g, 70 mmol) in water (30 mL). The reaction mixture was stirred at 60° C. for 16 hours, then was cooled to room temperature and the organic solvents were concentrated. The white solid residue was dissolved in hot water and then the product was neutralized with HCl (3 equivalents). After cooling to room temperature, the precipitate was filtered off, washed with water and dried in a vacuum oven overnight at 40° C.
