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By the use of the SIMPLE NMR method, strong intramolecular hydrogen bonds were found in the Me,SO solutions of sugars having two syn-axial hydroxy groups, like the talopyranoses. Weaker hydrogen bonds were detected between hydroxy groups in a 1,3-arrangement when one was outside the ring but only weak, although numerous, hydrogen bonds were detected in solutions of other sugars and inositols.The results described in this paper were obtained, independently, in London and Sydney, and were then correlated, with additional experiments, for publication. The work in London was a continuation of a series of papers on hydrogen bonds in Me2S0 solutions of sugars which, however, included only one monosaccharide (D-glUCOSe).5 The work in Sydney had the aim of establishing whether the substantial changes in the composition of some sugars when going from water to Me2S0 as solvent could be expained by the presence of intramolecular hydrogen bonds in the latter. Dais and Perlin ' suggested that

SIMPLE 'H n.m.r. measurements of glucose, maltose, and some of their derivatives in dimethyl sulphoxide solution confirm the inter-residue 2'-0H 9 . . 3-OH hydrogen bond in maltose and reveal the presence of weaker intra-residue hydrogen bonds between vicinal hydroxy groups in both glucose and maltose. Co-operative stabilisation of intra-residue hydrogen bonding is provided by the participation of the anomeric hydroxy group in glucose and by the inter-residue 2'-OH-3 OH hydrogen bond in maltose.

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SIMPLE 1H n.m.r. measurements of isotope-shifted resonances for hydroxy groups in sucrose show that hydrogen bonding in solution is different from that observed in the solid state viz. there are two inter-residue hydrogen bonds in competition for one acceptor group (i.e. OHI' ---0 2 vs. OH3' ---0 2 ) and an intramolecular hydrogen-bond network that is nucleated by the inter-residue hydrogen bonds.