X-Ray Examination of Sucrose

Abstract

ALTHOUGH the chemical structure of most sugars has been established beyond doubt, a given chemical structure may comprise several geometrical possibilities. In particular, the exact conformations of. the pyranose and furanose rings, which are of general occurrence in sugars and sugar derivatives, have long been the subject of speculation. An X-ray investigation of a series of sugars and their methyl derivatives was made by Cox, Goodwin and Wagstaff1, who came to the conclusion that the five carbon atoms of the pyranose ring lie in a plane but the oxygen atom is raised out of this plane. That this conclusion is not of universal application was shown by Cox and Jeffrey2, who determined the positions of all the atoms (other than hydrogen) in the crystal lattice of glucosamine hydrobromide, and were thus able to prove that in this case the pyranose ring is of the Sachse trans-form. Cox and Goodwin3 have suggested that the four carbon atoms and one oxygen which comprise the furanose ring are coplanar, but direct evidence has hitherto been entirely lacking. The sugars thus merit further attention by the methods of X-ray crystallography.