C(OC(=O)[C:5]([C:7]1(Br)[CH2:11][CH2:10][O:9][CH:8]1[O:12][CH2:13]C)=[O:6])C.S([O-])([O-])=O.[Na+].[Na+].[Cl-].[NH4+].Cl>ClCCl>[O:12]1[CH:8]2[O:9][CH2:10][CH2:11][CH:7]2[CH:5]([OH:6])[CH2:13]1To the solution of Ethyl-2-(3-bromo-2-ethoxy tetra hydrofuran-3-yl)-2-oxoacetate in dichloromethane (V, 500 mL) as prepared in above example, sodium sulphite solution (225 g was dissolved in 1700 mL of water) was added at 25-35° C. Reaction mass was stirred for 5-8 hours at the same temperature and separated the organic and aqueous layers. Organic layer was washed with water (340 mL). Distilled out the solvent completely get ethyl-2-(2-ethoxy tetra hydrofuran-3-yl)-2-oxoacetate. Sodium borohydride (35.5 g) was dissolved in ethanol (400 mL) under nitrogen atmosphere, ethyl-2-(2-ethoxytetra hydrofuran-3-yl)-2-oxoacetate was dissolved in ethanol (100 mL) and slowly added to above solution at 15-30° C. Reaction mass was heated to 30-45° C., maintained for 5-8 hours, the reaction mass temperature was raised to 55° C. and stirred for 8 hours. The reaction mass was cooled to 20-30° C., ammonium chloride solution (115 g in 200 mL water) was slowly added and stirred for 1-2 hours. The reaction mass was filtered and filtrate was distilled out under vacuum to get residue. Dichloromethane (600 mL) was added to residue and cooled to −10° C. Hydrochloric acid (85 mL) was added slowly drop wise in 2 hours by maintaining temp −5 to 0° C., reaction mass was stirred for 60 minutes at −5 to 0° C. and distilled the solvent completely. The obtained residue was stripped out with isopropyl alcohol (2×200 mL, 1×100 mL), ethyl acetate (500 mL) was added to the resultant residue, stirred for 30-60 minutes and cooled to 10-15° C. The solution was filtered and filtrate was concentrated to get title compound IV (yield 56 g).
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