p-Toluenesulfonic acid → 2,3:5,6-Di-O-isopropylidene-L-gulonolactone

関与物質

反応手順

m.p. 155° C. (from ethyl acetate) [α]D20 -76.6° (c, 1.99 in CHCl3), was prepared from L-gulonolactone in 85% yield as previously described by Fleet in copending application Ser. No. 249,153, filed Sept. 26, 1988. According to this method, the title compound is synthesized by treatment of L-gulonolactone with acetone and 2,2-dimethoxypropane and a catalytic amount of p-toluenesulfonic acid under dry nitrogen for 36 hours (h) followed by stirring with an excess of sodium bicarbonate, removing the solvent under reduced pressure, dissolving the residue in dichloromethane, washing with water, drying the organic extracts (MgSO4), removing the solvent under reduced pressure and recrystallizing from ethyl acetate to give a white crystalline solid.

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