Ammonium Chloride → (R)-4-((2R,4R,6R)-4-Amino-2-methoxy-6-(pent-4-enyl)-tetrahydro-2H-pyran-2-yl)-3-(4-methoxybenzyl)thiazolidin-2-one

Participants

Reaction Steps

A suspension of the title compound from Example 66 (432 mg, 0.967 mmol) in ethanol (3 mL) and water (1 mL) was treated with NH4Cl (122 mg, 2.27 mmol) and zinc dust (85.4 mg, 1.30 mmol), and the mixture was stirred vigorously at room temperature. After 6 h, an additional portion of zinc (100 mg) and NH4Cl (127 mg) was added, together with additional ethanol (4.5 mL) and water (1.5 mL), and stirring was continued for 18 h. Once more portions of zinc (100 mg) and NH4Cl (124 mg) were added, and stirring was continued. After 4 h, the mixture was diluted with ethyl acetate, washed with half-concentrated NH4OH and brine, dried, and concentrated. The residue was treated with NH4Cl (200 mg) in methanol (20 mL), and this mixture was allowed to stir at room temperature for 2 days. The mixture was diluted with ethyl acetate, washed with 1/1-satd aq NaHCO3/brine and then with brine, dried, and concentrated. Chromatography of the residue on silica gel eluting with methanol/dichloromethane gave the title compound (305 mg, 75%) as an oil.

Provenance & Evidence