The crystal structure of 3-amino-1,6-anhydro-3-deoxy-β-D-glucopyranose by neutron diffraction

Abstract

The crystal structure of 3-amino-l,6-anhydro-3-deoxy-/~-D-glucopyranose, C6H llNO4, has been determined from neutron diffraction data. The space group is P2~212~, Z=4, a= 7.804(8), b= 14.671 (16), c = 6.236 (8) A. The structure was solved by direct methods with MULTAN and refined anisotropically against Fo 2 to an R(F 2) value of 0-056. The molecular conformation has the amino group and the anhydro ring on the same side of a distorted ~C4 pyranose ring. The distortion is in the direction of a sofa conformation with the ring O out of plane. There are significant differences in the ring C-O bond lengths, which are similar to those observed in the methyl pyranosides. There is only one strong hydrogen bond in the crystal structure, OH • • • NH 2 at 1.760 A. The NH. • • O hydrogen bonds are weaker, at 2.212 and 2.258 ~,, and the N-H bonds are shorter, at 1.000 and 1.019 A, than generally found in the amino acid structures.

3-Ammonio-l,6-anhydro-3-deoxy-β-D-glucopyranose chloride monohydrate

“…The dimensions of the 3-ammonio cation are very similar to those of the neutral amine molecule (Noordik & Jeffrey, 1977). The glucopyranose ring is distorted from the regular IC 4 chair, being flatter at C(3) and sharper at 0(5).…”

The structure determination and molecular-mechanics calculation of 1,6-anhydro-β-D-galactopyranose

“…1 sequence and have been observed to be longer than normal both in other 1,6-anhydro sugars (cfi Table 3 in Noordik & Jeffrey, 1977) and in the linkage bonds between residues in oligosaccharides (cfi Table 5 in Jeffrey, Pople & Radom, 1974). Although this is also believed to be a consequence of the 'anomeric effect', it was not parameterized as such in MMI-CARB, as were the better-understood C(1)-O bond lengths and torsion potentials.…”

Syntheses of 3-deoxy-3-substituted-D-glucose derivatives. Part I. Improvements in preparation of and nucleophilic additions to 1,6:2,3-dianhydro-4-O-benzyl-β-D-allopyranose

“…(16), and its hydrochloride and other cationic derivatives exist predominantly in the latter conformation. Both compounds are present in the chair conformation in the solid state (36,37). One explanation considered for the unusual conformation of 18 was that the NH2 group was larger than an OH group (16).…”