Received 25 January 2006
aChemical Crystallography, Central Chemistry Laboratory, University of Oxford, Oxford OX1 3TA, England,bDepartment of Organic Chemistry, Chemical Research Laboratory, Oxford University, Mansfield Road, Oxford OX1 3TA, England, and cCMS Chemicals, 9 Milton Park, Abingdon, Oxfordshire OX14 4RR, England
Correspondence e-mail: firstname.lastname@example.org
The structures of both lactones derived from the Kiliani ascension of 2-C-methyl-D-threose were defined by the crystal structure of the title compound, C10H14O7. The structure consists of hydrogen-bonded ribbons of molecules.
The Kiliani reaction of ketoses with cyanide, followed by acetonation, has provided a simple and environmentally friendly procedure for the generation of a set of carbohydrate scaffolds with a branched hydroxymethyl group at C-2 (Hotchkiss et al., 2004; Soengas et al., 2005). Branched sugar lactones bearing a C-2 methyl group may be accessed either by a Kiliani reaction on 1-deoxyketoses or by treatment of an Amadori ketose with aqueous calcium hydroxide (Hotchkiss et al., 2006). X-ray crystallographic analysis has been crucial in establishing the structures of the products in these reactions (Punzo et al., 2006; Watkin et al., 2005; Harding et al., 2005). Although these syntheses provide convenient access to C-2 carbon-branched carbohydrates, there are very few reports of sugars with a carbon branch at C-3; a 3-C-methylpentonolactone of unknown stereochemistry has been isolated from cigarette smoke (Schumacher et al., 1977) and 3-C-methyl-D-mannose is one of the components of the trisaccharide repeating unit of the polysaccharide from Helicobacter Pylori (Kwon et al., 2004).
3-C-Methyl aldonolactones should be accessible through a Kiliani reaction on a branched 2-C-methyl aldose. Reaction of 2-C-methyl-D-threose (1) with aqueous sodium cyanide afforded an inseparable mixture of the C-3-methyl branched lactones (2) and (5); the mixture was treated with an excess of acetic anhydride in pyridine to give a separable mixture of two triacetates (3) and (6) together with a crystalline diacetate (4) (Soengas & Fleet, 2006). Determination of the relative stereochemistry of the diacetate (4) as a lyxono-1,4-lactone by X-ray crystallographic analysis (Fig. 1) allowed unambiguous structural assigments of both the triacetates (3) and (6), and thus of the C-3 branched lyxono- (2) and xylono- (5) lactones. The use of 2-C-methyl-D-threose (1) as the starting material in the synthesis defines the absolute configuration of (4). Both C-2 and C-3 branched sugars are likely to increase significantly the range of carbohydrate chirons (Lichtenthaler & Peters, 2004) available for the efficient synthesis of complex homochiral targets (Simone et al., 2005) and also to provide material for the first time for the study of interactions of such unnatural monosaccharides with biological receptors.
| || Figure 1 |
The title compound, with displacement ellipsoids drawn at the 50% probability level. The H atoms are shown as spheres of arbitary radius.
| || Figure 2 |
A b-axis projection showing layers of molecules. Dashed lines indicate hydrogen bonds.
| || Figure 3 |
A c-axis projection of one layer of molecules, showing the hydrogen-bonded (dashed lines) ribbons lying parallel to b.
The H atoms were all located in a difference map, but those attached to C atoms were repositioned geometrically. The H atoms were initially refined with soft restraints on the bond lengths and angles to regularize their geometry (C-H = 0.93-0.98 and O-H = 0.82 Å) and displacement parameters [Uiso(H) = 1.2-1.5Ueq of the parent atom], after which they were refined with riding constraints. In the absence of significant anomalous dispersion effects, Friedel pairs were averaged.
Data collection: COLLECT (Nonius, 2001).; cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: CAMERON (Watkin et al., 1996); software used to prepare material for publication: CRYSTALS.
Altomare, A., Cascarano, G., Giacovazzo, G., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.
Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.
Harding, C. C., Watkin, D. J., Sawyer, N. K., Jenkinson, S. F. & Fleet, G. W. J. (2005). Acta Cryst. E61, o1472-o1474.
Hotchkiss, D. J., Jenkinson, S. F., Storer, R., Heinz, T. & Fleet, G. W. J. (2006). Tetrahedron Lett. 47, 315-318.
Hotchkiss, D., Soengas, R., Simone, M. I., van Ameijde, J., Hunter, S., Cowley, A. R. & Fleet, G. W. J. (2004). Tetrahedron Lett. 45, 9461-9464.
Kwon, Y. T., Lee, Y. J., Lee, K. & Kim, K. S. (2004). Org. Lett. 6, 3901-3904.
Lichtenthaler, F. W. & Peters, S. (2004). C. R. Chim. 7, 65-90.
Nonius (2001). COLLECT. Nonius BV, Delft, The Netherlands.
Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.
Prince, E. (1982). Mathematical Techniques in Crystallography and Materials Science. New York: Springer-Verlag.
Punzo, F., Watkin, D. J., Hotchkiss, D. & Fleet, G. W. J. (2006). Acta Cryst. E62, o98-o100.
Schumacher, J. N., Green, C. R., Best, F. W. & Newell, M. P. (1977). J. Agric. Food. Chem. 25, 310-320.
Simone, M. I., Soengas, R., Newton, C. R., Watkin, D. J. & Fleet, G. W. J. (2005). Tetrahedron Lett. 46, 5761-5765.
Soengas, R. & Fleet, G. W. J. (2006). Tetrahedron Lett. In preparation.
Soengas, R., Izumori, K., Simone, M. I., Watkin, D. J., Skytte, U. P., Soetaert, W. & Fleet, G. W. J. (2005). Tetrahedron Lett. 46, 5755-5759.
Watkin, D. J. (1994). Acta Cryst. A50, 411-437.
Watkin, D. J., Parry, L. L., Hotchkiss, D. J., Eastwick-Field, V. & Fleet, G. W. J. (2005). Acta Cryst. E61, o3302-o3303.
Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, England.