Unusual Ring Contration by Substitution of 4-O-activated-pentono-1,5-lactams with cyanide. Stereospecific Synthesis of 6-Amino-1,4,5,6-tetradeoxy-1,4-imino-hexitols

Reaction of 4-O-sulfonylated 2,3-O-isopropylidene-D-ribo- or -D-lyxo-1,5-lactams with tetrabutylammonium cyanide gave 4-amino-5-C-cyano-4,5-dideoxy-2,3-O-isopropylidene-L-lyxo-5 or -L-ribo-15-1,4-lactams, respectively. A stereospecific ring contraction with inversion at C-4 had taken place in each case.

Reduction of the cyanolactams with LiAlH4 gave 6-amino-1,4,5,6-tetradeoxy-1,4-imino-L-lyxo-6 or -L-ribo-16-hexitol, respectively. The 6-amino-1,4,5,6-tetradeoxy-1,4-imino-L-ribo-hexitol 16 was found to be a moderate inhibitor of alpha-L-fucosidase with a K-i of 110 mu M. (C) 2000 Elsevier Science Ltd.

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