1-Deoxy-d-arabinitol

Addition of methyl lithium to d-erythrono-1,4-lactone followed by acid deprotection was shown, by X-ray crystallography, to give 1-deoxy-d-arabinitol, C5H12O4, rather than 1-deoxy-d-ribitol as the major product. The crystal structure exists as hydrogen-bonded chains of molecules running parallel to the c axis which are further linked together by hydrogen bonds. Each molecule is a donor and an acceptor for four hydrogen bonds.

Addition of methyl lithium to d-erythrono-1,4-lactone followed by acid deprotection was shown, by X-ray crystallography, to give 1-deoxy-d-arabinitol, C 5 H 12 O 4 , rather than 1-deoxy-d-ribitol as the major product. The crystal structure exists as hydrogen-bonded chains of molecules running parallel to the c axis which are further linked together by hydrogen bonds. Each molecule is a donor and an acceptor for four hydrogen bonds.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH2622).

Comment
The demand for the large scale production of rare sugars by biotechnological (Izumori, 2006;Izumori, 2002;Granstrom et al., 2004) and chemical (Beadle et al., 1992) methods is driven by the demand for alternative foodstuffs (Skytte, 2002) and D-tagatose itself is used as a low calorie sweetener (Levin, 2002;Howling & Callagan, 2000;Bertelsen et al. 1999) Rare monosaccharides have been found to demonstrate interesting pharmaceutical properties, for example, D-psicose (Takata et al., 2005;Menavuvu et al., 2006) and D-allose (Sui et al., 2005;Hossain et al., 2006) have significant chemotherapeutic properties and D-tagatose has been found to be an anti-hyperglycemic agent (Zehner et al., 1994;Donner et al., 1999) and therefore potentially useful in the treatment of diabetes.
The methodology developed by Izumori et al. (2002Izumori et al. ( , 2006 for the interconversion of tetroses, pentoses and hexoses by enzymatic oxidation, inversion at C3 with a single epimerase, and reduction to the aldose has been seen to be generally applicable for the 1-deoxy ketohexoses (Yoshihara et al., 2008). In order to investigate the viability of this process to the corresponding pentoses and thus to evaluate their therapeutic potential 1-deoxy-D-arabinitol was synthesized, in 3 steps, from 2,3-O-isopropylidene-D-erythronolactone 1 (Fig.1). It has previously been seen that the four diastereomeric tetraols are very difficult to distinguish between by NMR spectroscopy (Takai & Heathcock, 1985). X-ray crystallography confirmed that the major product was the arabinitol 4 rather than the ribitol 3 which differs only in the stereochemistry at the C2 position (Fig. 2).
In summary, the stereochemistry at C2 of the title compound 1-deoxy-D-arabinitol 4 was firmly established by X-ray crystallography, the absolute configuration is determined by the use of D-erythronolactone as the starting material. As well as the potential biological properties of 1-deoxy ketoses, they are likely to provide a new set of building blocks for the synthesis of a wide variety of complex biomolecules.

Refinement
In the absence of significant anomalous scattering, Friedel pairs were merged and the absolute configuration assigned from the starting material.
supplementary materials sup-2 The H atoms were all located in a difference map, but those attached to carbon 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 in the range 0.93-0.98, O-H = 0.82 Å) and U iso (H) (in the range 1.2-1.5 times U eq of the parent atom), after which the positions were refined with riding constraints. Fig. 1. Synthetic scheme.