SYNTHESIS, CHARACTERIZATION, AND CONFORMATION IN SOLUTION OF A NOVEL D-GLUCURONO-6,1-LACTAM DERIVATIVE

Article abstract of DOI:10.1016/S0008-6215(00)81072-1

Prolonged treatment of 2'-(sodium β-D-glucopyranosyluronate)isonicotinohydrazide with acetic anhydride in the presence of pyridine at room temperature for <*>110 h gave 2,3,4-tri-O-acetyl_gN-(diacetylamino)-β-D-glucopyranurono-1,6-lactam (2), a novel D-glucurono-6,1-lactam derivative.Its conformation in solution, examined by 1H- and 13C-n.m.r. and compared with the crystal structure, corresponds to a fairly rigid ring system, the pyranose ring adopting a near B_0,3 (D) boat form in solution and a distorted ¹C₄ (D) chair conformation in the crystalline state.The closely related 2,3,4-tri-O-acetyl-β-D-glucopyranurono-6,1-lactone (4) and 2,3,4-tri-O-acetyl-1,6-anhydro-β-D-glucose (3) take the distorted ¹C₄ (D) chair conformation, both in solution and in crystal form.Based on the crystal structure data of 4, the parameters of the Karplus-type equation, which relates vicinal-coupling constants with dihedral angles, were determined for 2,3, and 4.