O-Protected 3-hydroxy-oxazolidin-2,4-diones: novel precursors in the synthesis of alpha-hydroxyhydroxamic acids

O-Protected 3-hydroxyoxazolidin-2,4-diones have been prepared in a novel one-pot reaction by subsequent treatment of cyanohydrins with 1,1'-carbonyldiimidazole and O-protected hydroxylamines followed by acidic hydrolysis of the intermediate 4-imino-oxazolidin-2-ones. Decarbonylation of O-protected 3-hydroxyoxazolidin-2,4-diones by catalytic amounts of sodium methoxide, lithium hydroxide, sodium carbonate and caesium carbonate in methanol afforded O-protected alpha-hydroxyhydroxamic acids in excellent yields. Their deprotection provided a series of novel alpha-hydroxyhydroxamic acids.