Pyridine → 3,4-dihydroxy-5-(2-iodoethyl)-2(5H)-furanone

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a dry flask flushed with argon was added 0.72 g (2.0 mmol) of 3-benzyloxy-4-hydroxy-5-(2-iodoethyl)-2(5H)-furanone and 10 mL of CH2Cl2. The solution was cooled with stirring in an ice-water bath, and 0.38 mL (4.0 mmol) of acetic anhydride and 0.34 mL (4.2 mmol) of pyridine were added. The ice bath was removed and the solution was stirred for 1 hour. All volatile substances were removed in vacuo (2 h at 1 mm Hg, 25° C.). Argon was introduced to the reaction flask and the residue was taken up in 20 mL of dry CH2Cl2, cooled to -78° C. and 5.2 mL (2.6 mmol) of 1.0M BCl3 in CH2Cl2 was added with stirring. The reaction mixture was kept at -78° C. for 1 hour and at room temperature for 30 minutes. The mixture was poured into 50 mL of brine and extracted with 3×30 mL of ether. The combined ether extracts were washed with 5 mL of H2O and extracted into saturated NaHCO3 solution (3×15 mL). The bicarbonate fractions were pooled and washed with 15 mL of ether, acidified to pH 1 with 25% aqueous HCl solution, and extracted with 3×30 mL of ether. The ether extracts were combined and washed with 15 mL of brine, dried (MgSO4) and concentrated to provide 360 mg (67% yield) of 3,4-dihydroxy-5-(2-iodoethyl)-2(5H)-furanone as a white crystalline solid: mp 150-151° C.; 1H NMR (acetone-d6) δ 4.80 (dd, 1H, J=3.5, 8.0 Hz), 3.50-3.25 (m, 2H), 2.60-2.35 (m, 1H), 2.20-1.95 (m, 1H). Anal Calcd for C6H7O4I: C, 26.69; H, 2.61. Found: C, 26.54; H, 2.59.

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