Synthesis and structure determination of some sugar amino acids related toalanine and 6-deoxymannojirimycin

(5 'R)-5 ' -Methyl-5 '-[methyl (4S)-2,3-O-isopropylidene-beta -L-erythrofur anosid-4-C-yl]-imidazolidin-2 ' -4 ' -dione was synthesised starting from m ethyl 6-deoxy-2,3-O-isopropylidene-alpha -D-lyxo-hexofuranosid-5-ulose appl ying the Bucherer-Bergs reaction. Its 5 ' -R configuration was confirmed by X-ray crystallography. Corresponding a-amino acid-methyl (5R)-5-amino-5-C- carboxy-5,6-dideoxy-alpha -D-lyxo-hexofuranoside (alternative name: 2-methy l (4S)-2,3-O-isopropylidene- beta -L-erythrofuranosid-4-C-yl]-D-alanine was obtained from the above hydantoin by acid hydrolysis of the isopropylidene group followed by basic hydrolysis of the hydantoin ring. Total deprotecti on afforded 5- C-carboxy-6-deoxymannojirimycin. Analogously, methyl (5S)-5- amino-5- C-carboxy-5,6-dideoxy-alpha -L-lyxo-hexofuranoside and 5- C-carbox y-6-deoxy-L-mannojirimycin were prepared from the corresponding (5 'S)-5 ' -methyl-5 ' [methyl 14r -2, 3-O-isopropylidene-beta -D-erythrofuranosid-4-C -yl] -imidazolidin-2 ' ,4 ' -dione starting from methyl 6-deoxy-2,3-O-isopr opylidene-alpha -L-lyxo-hexofuranosid-5-ulose. (C) 2001 Published by Elsevi er Science Ltd.