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

2,3 : 5,6-di-O-isopropylidene-2-C-hydroxy-methyl-D-talono-1,4-lactone

The title diacetonide, C13H20O7, readily available in quantity from D-tagatose, is likely to be a useful carbohydrate starting material. The current structure analysis resolves any ambiguities arising from the synthetic route over the configuration at the new chiral centre and the size of the lactone ring, but otherwise shows no unusual features. © 2004 International Union of Crystallography Printed in Great Britain - all rights reserved

Kiliani reactions on ketoses: branched carbohydrate building blocks from D-tagatose and D-psicose

D-Tagatose and D-psicose on treatment with sodium cyanide gave mixtures of branched sugar lactones; extraction of the crude products by acetone in the presence of acid permits direct access to branched carbohydrate diacetonides, likely to be of value as new chirons. In both cases, the major lactone products-diacetonides with a 2,3-cis-diol relationship-can be crystallised in around 40-50% yield from the ketohexose. A practical procedure for the conversion of 30 g of D-tagatose to give 24 g of 2,3:5,6-di-O-isopropylidene-2- C-hydroxymethyl-D-talono-1,4-lactone is reported. © 2005 Elsevier Ltd. All rights reserved

1,2 : 3,4-Di-O-isopropylidene-alpha-D-tagatofuranose

The crystal structure of diacetone tagatose, C12H 20O6, establishes the stereochemistry of the anomeric spiroacetal as 1,2:3,4-di-O-isopropylidene-α-D-tagatofuranose. Molecules are linked by O - H⋯O hydrogen bonds [O⋯O = 2.862 (2) Å] to form chains running parallel to the b axis. © 2005 International Union of Crystallography Printed in Great Britain - all rights reserved