To a stirred solution of step-1 Intermediate (1.8 g, 7.76 mmol) in methanol (20 mL) were added tin(II) chloride dihydrate (5.88 g, 31.0 mmol) followed by the addition of concentrated HCl (1.65 mL, 54.3 mmol) at room temperature. The resulting mixture was heated at 75° C. for 2 h. Then the reaction was allowed to room temperature and the solvent was removed under reduced pressure. The crude mass was diluted with ethyl acetate (100 mL), basified with aqueous ammonia (pH 14) and the resulting solid suspension was filtered through Celite bed. The residue was washed with ethyl acetate (2×50 mL). The combined filtrates were washed with water (50 mL), brine (50 mL), dried (NaTo a stirred solution of step-1 Intermediate (1.8 g, 7.76 mmol) in methanol (20 mL) were added tin(II) chloride dihydrate (5.88 g, 31.0 mmol) followed by the addition of concentrated HCl (1.65 mL, 54.3 mmol) at room temperature. The resulting mixture was heated at 75° C. for 2 h. Then the reaction was allowed to room temperature and the solvent was removed under reduced pressure. The crude mass was diluted with ethyl acetate (100 mL), basified with aqueous ammonia (pH 14) and the resulting solid suspension was filtered through Celite bed. The residue was washed with ethyl acetate (2×50 mL). The combined filtrates were washed with water (50 mL), brine (50 mL), dried (Na
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