[BH4-].[Na+].C(OC(=O)[C:7]([CH:9]1[CH2:13][CH2:12][O:11][CH:10]1[O:14][CH2:15]C)=[O:8])C.[Cl-].[NH4+].C(N(CC)CC)C>C(O)C>[O:14]1[CH:10]2[O:11][CH2:12][CH2:13][CH:9]2[CH:7]([OH:8])[CH2:15]1
Dissolve sodium borohydride (35.5 g) in ethanol (400 ml) under nitrogen atmosphere. Ethyl-2-(2-ethoxytetrahydrofuran-3-yl)-2-oxoacetate (100 g) was dissolved in Ethanol (100 ml) and slowly added at 15-30° C. Reaction mass was then maintained at 50-60° C. for 8 hrs. Reaction mass was cooled to 20-30° C. and slowly added ammonium chloride solution (57.5 g in 100 ml water) and stirred for 1 hrs. Reaction mass was filtered and filtrate was distilled out under vacuum to residue. Dichloromethane (400 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 0 to −10° C. Reaction temp was maintained for 1 hr at 0 to −10° C. Triethyl amine (91.3 g) was added to the reaction mass at 0 to −10° C. and reaction mass was stirred for 1 hour at 0 to −10° C. Reaction mass was concentrated to residue. Residue was stripped out with Ethyl acetate (2×100 ml). Ethyl acetate (500 ml) was added to the residue and cooled to 10-15° C. Reaction mass was then filtered off and filtrate was concentrated to residue to get Hexahydrofuro[2,3-b]furan-3-ol (Yield 56 g).
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