Two syntheses of 3-amino-3-deoxy-α- d-altropyranosyl 3-amino-3-deoxy-α- d-altropyranoside, a new analog of α,α-trehalose, involing reduction of a diazide and reductive amination of a diketone

Abstract

A new diamino sugar, 3-amino-3-deoxy-α- d-altropyranosyl 3-amino-3-deoxy-α- d-altropyranoside ( 5) was synthesized by two routes starting from α,α-threhalose. The first route involved reduction and deprotection of a previously described, benzylidenated diazido analog. The second approach proceeded from the known 2,2′-di- O-benzyl-4,6;4′,6′-bis- O-benzylidene derivative of α- d-altropyranosyl α- d-altropyranoside, to the corresponding 3,3′-diketone, which was subjected to reductive amination with sodium cyanoborohydride and ammonium acetate. The major product, separated in 39% yield from by-products after N-acetylation, was deprotected to give 5. Four by-products were isolated in low yields and determined to be monoaminated analogs which comprise two epimeric, 3′-hydroxy structures and two 3′-epimeric, 3′-cyano-3′-hydroxy structures in their non-aminated residues. A number of observations concerning the 13C- and 1H-n.m.r. spectra of the products are discussed, especially with regard to chemical-shift dependencies for certain ring and substituent protons, and attention is drawn to some inter-residue shielding phenomena.