Arylazo-glycenosides. Part 7. Syntheses of amino-sugars from methyl arylazo-hexenopyranosides

Abstract

Reaction of the anhydro-glycopyranosiduloses (1) and (2) with o-nitro- and o,p-dinitro-phenylhydrazine yielded the hydrazones (3)–(6), whereas phenyl- or p-nitrophenyl-hydrazine yielded the phenylazoalkenes (7)–(10), formed by rearrangement of intermediate hydrazones. Reaction of the azoalkanes (8) and (9) with a range of nuceophiles yielded the α-substituted phenylhydrazones (11)–(19) and (24)–(28), respectively, by 1,4-addition. It has been shown that the α-amino-hydrazones (20), (25), and (28) can be reduced to vicinal diaminosugars, thereby providing a new route to these compounds. Reduction of the azoalkene (9) yielded the 2-amino-2,3,6-trideoxy-hexopyranoside, isolated as the ON-diacetyl derivative (31).