THE PREPARATION OF L-LYXURONIC ACID, L-LYXOSE, AND 5-DEOXY-L-LYXOSE

Abstract

D-Galactono-1,4-lactone (I) was oxidized by 1 mole of periodate to give L-lyxuronic acid isolated as methyl L-lyxuronate (II). The methyl L-lyxuronate was converted into methyl (methyl α-L-lyxofuranosid)uronate (III) which on reduction by borohydride afforded methyl α-L-lyxofuranoside (IV) from which L-lyxose (V) was obtained by mild acid hydrolysis.5-Deoxy-L-lyxose was prepared from the methyl (methyl α-L-lyxofuranosid)uronate (III) by the following sequence of reactions: (III) → methyl (methyl 2,3-O-isopropylidene-α-L-lyxo-furanosid)uronate (VI) → methyl 2,3-O-isopropylidene-α-L-lyxofuranoside (VII) → methyl 2,3-O-isopropylidene-5-O-(p-tolylsulfonyl)-α-L-lyxofuranoside (VIII) → methyl 5-deoxy-5-iodo-2,3-O-isopropylidene-α-L-lyxof uranoside (IX) → methyl 5-deoxy-2,3-O-isopropylidene-α-L-lyxofuranoside (X) → 5-deoxy-L-lyxose (XI).