Nitrogen-containing Sugars. IV

Abstract

Condensation of 1, 3, 4, 6-tetraacetyl-β-D-glucosamine (I) and phthalic anhydride affords 1, 3, 4, 6-tetraacetyl- N-phthaloyl-β-D-glucosamine (II) whose reaction with hydrogen bromide in glacial acetic acid and acetic anhydride mixture gives 3, 4, 6-triacetyl-1-bromo compound (III). Reaction of (III) with methanol in the presence of silver carbonate results in the formation of methyl 3, 4, 6-triacetyl-N-phthaloyl-β-D-glucosaminide (IV), which is also obtained on boiling (II) with 5% methanolic hydrochloric acid until the optical rotation becomes definite and subsequent acetylation. Condensation of (II) and phenol results in the formation of phenyl 3, 4, 6-triacetyl-N-phthaloyl-β-D-glucosaminide (IX), whether the catalyst used is p-toluene-sulfonic acid or zinc chloride. As shown by the foregoing, substitution reaction of C-1 position in (II) chiefly results in the formation of a β-bonding and the formation of α-bonding is markedly obstructed. This is thought to be due to the bulky phthalimide group in C-2 position that causes a great resistance to the formation of a half-chair form (XIII), assumed to be the intermediate in the formation of α-bonding from C-1 conformation (XII).