2,2': 5,6-Di-O-isopropylidene-2-C-hydroxy-methyl-D-talono-1,4-lactone

A second crystalline diacetonide, the title compound, C13H 20O7, has been isolated from the sequential treatment of D-tagatose with aqueous sodium cyanide, followed by acetone in the presence of acid. Structural ambiguities with regard to the size of both the lactone and ketal rings are resolved by the X-ray crystallographic analysis. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved