Crystal and molecular structure of maltotriitol (4-O-α-D-glucopyranosyl-4-O-α-D-glucopyranosyl-D-glucitol)

The crystal structure of maltotriitol (4-O-alpha-D-glucopyranosyl-4-O-alpha-D-glucopyranosyl-D-glucitol) was determined by X-ray diffraction at 150 K and refined to a final conventional parameter of R = 0.043. The two glucopyranosyl moieties adopt the C-4(1) conformation. The conformation of the glucitol fragment exhibits a [AAP(PA)] bent-chain, sickle conformation of the carbon chain. This results in a 1,3-parallel O//O interaction between O-22 and O-11 and a nearly parallel C//O interaction between C-26 and O-23. The occurrence of a parallel O//O interaction next to a parallel C//O interaction is unique in the class of alditols. All hydroxyl groups are involved in a bifurcated intermolecular hydrogen-bond network, which consists of a finite chain joined by a very short finite chain. The conformation about the glycosidic link between the pyranosyl moieties is stabilized by one intramolecular hydrogen bond, whereas the link between the pyranosyl and glucitol moieties is stabilized by two intramolecular hydrogen bonds. The parallel C//O interaction in the glucitol fragment enables the formation of a symmetric bifurcate C-26-H ... O interaction. (C) 1999 Elsevier Science Ltd. All rights reserved.