Hydrochloric Acid → 2,6-Anhydro-3,4,5-trideoxy-3-[[(1,1-dimethylethoxy)carbonyl]amino]-D-erythro-hexonic acid

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirring solution of [(2R,3R)-2-formyl-tetrahydro-pyran-3-yl]-carbamic acid tert-butyl ester (57.7 mg, 0.251 mmol)in methylene chloride (2 mL) was added tetramethyl-ammonium bromide (4.1 mg, 0.012 mmol) and 2,2,6,6-tetramethyl-1-piperidinyloxy, free radical (1 mg, 0.003 mmol), followed by a solution of potassium bromide (3 mg, 0.03 mmol) in water (1 mL). Upon cooling the mixture to 0° C., aqueous sodium hypochlorite (3.6 mL, 0.35 M) made pH 8.6 with sodium bicarbonate (50 mg/mL of 0.35 M NaOCl) was added, and the resulting yellow/orange mixture was stirred vigorously for 5 min. The reaction was poured into 1N aqueous sodium hydroxide (50 mL), acidified with 1N aqueous hydrogen chloride (55 mL), and washed with ethyl acetate (3×50 mL). The combined organic layers were dried over sodium sulfate, concentrated in vacuo, and the resulting residue was purified by flash chromatography (SiO2, 30-50% ethyl acetate in hexanes then 70% ethyl acetate in hexanes containing 5% acetic acid and 1% methanol) to give the desired product (55.5 mg, 89.5%) as a foamy solid. MS (ESI), m−/z: (M−H)−=244.

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