Efficient synthesis from d-lyxonolactone of 2-acetamido-1,4-imino-1,2,4-trideoxy-l-arabinitol LABNAc, a potent pyrrolidine inhibitor of hexosaminidases

The synthesis from d-lyxonolactone of 2-acetamido-1,4-imino-1,2,4-trideoxy-l-arabinitol LABNAc proceeded in an overall yield of 25%; the enantiomer, 2-acetamido-1,4-imino-1,2,4-trideoxy-d-arabinitol DABNAc, was prepared from l-lyxonolactone. LABNAc and N-benzyl LABNAc are potent non-competitive inhibitors of d-hexosaminidase, whereas N-benzyl DABNAc exhibits weak competitive inhibition of the enzyme; this provides further evidence in support of Asano's hypothesis that while d-imino sugar mimics inhibit d-glycohydrolases competitively, their l-enantiomers show non-competitive inhibition and in the case of iminofuranoses l-enantiomers are usually more potent inhibitors.