organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoSTRUCTURAL
CHEMISTRY
ISSN: 2053-2296

The concomitant crystallization of two polymorphs of 1-de­­oxy-α-D-tagatose

CROSSMARK_Color_square_no_text.svg

aDepartment of Organic Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, England, bRare Sugar Research Centre, Kagawa University, 2393 Miki-cho, Kita-gun, Kagawa 761-0795, Japan, and cDepartment of Chemical Crystallography, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, England
*Correspondence e-mail: nigel.jones@chem.ox.ac.uk

(Received 24 October 2006; accepted 14 November 2006; online 12 December 2006)

The crystalline form of 1-de­oxy-D-tagatose, C6H12O5, is shown to be 1-de­oxy-α-D-tagatopyranose; the absolute configuration is determined by use of D-lyxono-1,4-lactone as the starting material. The title compound crystallized as concomitant polymorphs from a mixture of ethyl actate and methanol. Although the melting points of the materials differ by 7 K, the mol­ecular conformations are almost identical and, in both polymorphs, each mol­ecule is subject to four O—H⋯O hydrogen bonds.

Comment

The properties of 1-de­oxy ketohexose sugars have been little studied. The crystal structure of 1-de­oxy-D-sorbose has recently been published (Jones et al., 2006[Jones, N. A., Fanefjord, M., Jenkinson, S. F., Fleet, G. W. J. & Watkin, D. J. (2006). Acta Cryst. E62, o4663-o4665.]) and as part of a project to extend the range of simple monosaccharide derivatives, 1-de­oxy-D-tagatose, (2)[link], was synthesized. 1-De­oxy-D-tagatose has previously been synthesized (Wolfrom & Bennett, 1965[Wolfrom, M. L. & Bennett, R. B. (1965). J. Org. Chem. 30, 1284-1287.]; Dills & Covey, 1981[Dills, W. L. & Covey, T. R. (1981). Carbohydr. Res. 89, 338-341.]; Cubero & Poza, 1985[Cubero, I. & Poza, D. G. (1985). Carbohydr. Res. 138, 139-142.]), but no crystal structure has been reported.

[Scheme 1]

The demand for the large-scale production of rare sugars by biotechnological (Izumori, 2002[Izumori, K. (2002). Naturwissenschaften, 89, 120-124.], 2006[Izumori, K. (2006). J. Biotechnol. 124, 717-722.]; Granstrom et al., 2004[Granstrom, T. B., Takata, G., Tokuda, M. & Izumori, K. (2004). J. Biosci. Bioeng. 97, 89-94.]) and chemical (Beadle et al., 1992[Beadle, J. R., Saunders, J. P. & Wajda, T. J. (1992). US Patent No. 5 078 796.]) methods is driven by the demand for alternative foodstuffs (Skytte, 2002[Skytte, U. P. (2002). Cereal Foods World, 47, 224.]) and D-tagatose itself is used as a low-calorie sweetener (Levin, 2002[Levin, G. V. (2002). J. Med. Food, 5, 23-36.]; Howling & Callagan, 2000[Howling, D. & Callagan, J. L. (2000). PCT Int. Appl. WO 2000042865.]; Bertelsen et al. 1999[Bertelsen, H., Jensen, B. B. & Buemann, B. (1999). World Rev. Nutr. Diet, 85, 98-109.]). Rare monosaccharides themselves, however, have been found to demonstrate inter­esting pharmaceutical properties; for example, D-psicose (Takata et al., 2005[Takata, M. K., Yamaguchi, F., Nakanose, Y., Watanabe, Y., Hatano, N., Tsukamoto, I., Nagata, M., Izumori, K. & Tokuda, M. (2005). J. Biosci. Bioeng. 100, 511-516.]; Menavuvu et al., 2006[Menavuvu, B. T., Poonperm, W., Leang, K., Noguchi, N., Okada, H., Morimoto, K., Granstrom, T. B., Takada, G. & Izumori, K. (2006). J. Biosci. Bioeng. 101, 340-345.]) and D-allose (Sui et al., 2005[Sui, L., Dong, Y. Y., Watanabe, Y., Yamaguchi, F., Hatano, N., Tsukamoto, I., Izumori, K. & Tokuda, M. (2005). Int. J. Oncol. 27, 907-912.]; Hossain et al., 2006[Hossain, M. A., Wakabayashi, H., Izuishi, K., Okano, K., Yachida, S., Tokuda, M., Izumori, K. & Maeta, H. (2006). J. Biosci. Bioeng. 101, 369-371.]) have significant chemotherapeutic properties and D-tagatose has been found to be an antihyperglycemic agent (Zehner et al., 1994[Zehner, L. R., Levin, G. V., Saunders, J. P. & Beadle, J. R. (1994). US Patent No. 5 356 879.]; Donner et al., 1999[Donner, T. W., Wilber, J. F. & Ostrowski, D. (1999). Diabetes Obes. Metab. 1, 285-291.]) and therefore potentially useful in the treatment of diabetes.

1-De­oxy-D-tagatose, (2)[link], was synthesized from protected D-lyxono-1,4-lactone, (1)[link], by methyl­ation using methyl lithium and subsequent deprotection with dowex resin (H+) (Jones et al., 2007[Jones, N. A., Jenkinson, S. F., Soengas, R., Fanefjord, M., Wormald, M. R., Dwek, R. A., Izumori, K. & Fleet, G. W. J. (2007). In preparation.]). The de­oxy sugar was readily crystallized and the present paper firmly establishes that, as for 1-de­oxy-D-sorbose (Jones et al., 2006[Jones, N. A., Fanefjord, M., Jenkinson, S. F., Fleet, G. W. J. & Watkin, D. J. (2006). Acta Cryst. E62, o4663-o4665.]), 1-de­oxy-D-tagatose exists in the crystalline state as the α-anomer of the pyran­ose ring form (3)[link], in a chair conformation. Two polymorphic forms were observed to crystallize from the same mother liquor but at different rates. The two forms were needles and hexagonal plates. The hexagonal plates were found to crystallize out after 16 h, whereas the needles were only observed after 72 h. In both polymorphic forms, the title compound was in the α-pyran­ose form (3)[link]. In contrast, in aqueous solution it exists as an equilibrium mixture of the open chain, (2)[link], α-pyran­ose, (3)[link], α-furan­ose, (4)[link], β-pyran­ose, (5)[link], and β-furan­ose, (6)[link], forms.

Crystals of two distinctly different habits, viz. needles and plates, were observed in approximately equal quantities in the mother liquor. Cell parameters were determined for both forms and found to be different. Full data collections and structure solutions were performed on a sample of each habit. With the exception of the hydroxyl H atoms, the mol­ecules were essentially identical (Figs. 1[link] and 2[link]), with an r.m.s. displacement between equivalent atoms of 0.05 Å after superimposing one mol­ecule on the other.

The formation of two different polymorphs of a material simultaneously in the same environment is termed `concomitant polymorphism' (Bernstein et al., 1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]). There seems to be some uncertainly about the frequency of occurrence of this phenomenon. Bernstein et al. (1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]) remark that it is rarely reported in the recent literature, but that it had been widely observed (von Groth et al., 1906[Groth, P. H. R. von (1906). An Introduction to Chemical Crystallography, translated by H. Marshall, pp. 28-31. London: Gurnery & Jackson.]) before the advent of X-ray crystallography. Perhaps this is because the thrust of many structure determinations has been focused on the mol­ecular structure rather than the crystal structure, so that the work was performed on the first good quality crystal obtained rather than on a survey of a whole batch of material. Bowes et al. (2003[Bowes, K. F., Glidewell, C., Low, J. N., Skakle, J. M. S. & Wardell, J. L. (2003). Acta Cryst. C59, o1-o3.]) support this: `our identification, essentially by chance, of four such examples within a rather short space of time suggests to us that the phenomenon of concomitant polymorphism may, in fact, be a rather common one, certainly far more common than the current literature tends to suggest, but one which goes largely unnoticed.' In recent years, the current authors have analysed almost 100 saccharide derivatives and this is the first one where polymorphism was clearly evident.

The different polymorphs arise from differences in the hydrogen-bonding network (Figs. 3[link] and 4[link], and Tables 1[link] and 2[link]). The most densely packed mol­ecules occur in the plate-like crystals. As is usual in P212121, the mol­ecules are linked into hydrogen-bonded helices around the twofold screw axes. The relationship between the two polymorphs is most easily visualized by concentrating on the helices containing atoms O7 and O10. In the more dense polymorph, this is a helix involving four mol­ecules. One turn consists of the sequence O7—H7⋯O10—H10⋯O7—H7⋯O10—H10⋯O7. In projection along the a axis, the four O atoms form an approximate square (Fig. 4[link]). In the less dense polymorph, the helix is expanded to contain contributions from six mol­ecules. Atom O10 still donates to atom O7, but atom O7 is now linked via atoms O8 and O9 back to an equivalent mol­ecule that uses atom O10. One turn of this extended sequence contains O10—H10⋯O7—H7⋯O8⋯H9—O9 and the same pattern repeated by symmetry (Fig. 3[link]). In the plate-like crystal, mol­ecules 1 and 2 lie more or less side by side. In the needle-shaped crystals they are displaced with respect to each other so that the cross-section of the helix becomes oval. Other O—H⋯O hydrogen bonds crosslink these helices. There are no unusually short intermol­ecular contacts.

In summary, 1-de­oxy-D-tagatose, (2), exists in the crystalline state as 1-de­oxy-α-D-tagatopyran­ose, (3); the absolute configuration is determined by the use of D-lyxono-1,4-lactone as the starting material. The X-ray crystal structure determined the stereochemistry at the anomeric position as being α, with the hydroxyl group in the axial position. 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.

The crystallographic interest in these materials arises from the concomitant polymorphism, few cases of which are reported in the literature, but which may eventually be of use for the fine-tuning of structure prediction programs.

[Figure 1]
Figure 1
The title compound from the needle crystals, with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radii.
[Figure 2]
Figure 2
The title compound from the hexa­gonal plate crystals, with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitrary radii.
[Figure 3]
Figure 3
Part of the three-dimensional hydrogen-bonding network in the needle crystals, viewed approximately parallel to a and showing one turn of the helix (starting from the mol­ecule with symmetry code ii). Mol­ecules labelled 1 and 2 are described in the Comment. [Symmetry codes: (i) x, y − 1, z; (ii) x − [{1\over 2}], −y + [{1\over 2}], −z + 1; (iii) x − [{1\over 2}], −y + [{3\over 2}], −z + 1; (iv) x + [{1\over 2}], −y + [{1\over 2}], −z + 1; (v) −x + 2, y − [{1\over 2}], −z + [{1\over 2}]; (vi) −x + [{3\over 2}], −y + 1, z + [{1\over 2}].]
[Figure 4]
Figure 4
The equivalent part of the three-dimensional hydrogen-bonding network in the plate crystals, viewed approximately parallel to a and showing one turn of the helix (starting from the mol­ecule with symmetry code i). In strict a-axis projection, the sides of the helix form an almost square lozenge. Mol­ecules labelled 1 and 2 are described in the Comment. [Symmetry codes: (i) x − 1, y, z; (ii) x, y + 1, z; (iii) x − [{1\over 2}], −y + [{1\over 2}], −z + 1; (iv) x − [{1\over 2}], −y + [{3\over 2}], −z + 1.]

Experimental

The title compound was recrystallized from a mixture of ethyl acetate and methanol to give colourless crystals; [α]D22 −13 (c 2.0, H2O). The melting points of the two crystalline forms were found to be different, viz. 409–411 K for the needles and 416–418 K for the hexagonal plates.

Polymorph (I)[link]

Crystal data
  • C6H12O5

  • Mr = 164.16

  • Orthorhombic, P 21 21 21

  • a = 6.0243 (2) Å

  • b = 7.5022 (3) Å

  • c = 15.9717 (8) Å

  • V = 721.85 (5) Å3

  • Z = 4

  • Dx = 1.510 Mg m−3

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 190 K

  • Needle, colourless

  • 0.40 × 0.10 × 0.10 mm

Data collection
  • Nonius KappaCCD diffractometer

  • ω scans

  • Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) Tmin = 0.829, Tmax = 0.987

  • 5125 measured reflections

  • 975 independent reflections

  • 879 reflections with I > 2σ(I)

  • Rint = 0.057

  • θmax = 27.5°

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.029

  • wR(F2) = 0.069

  • S = 1.00

  • 975 reflections

  • 100 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(F2) + (0.03P)2 + 0.18P], where P = [max(Fo2,0) + 2Fc2]/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.21 e Å−3

  • Δρmin = −0.19 e Å−3

Table 1
Hydrogen-bond geometry (Å, °) for polymorph (I)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
O7—H7⋯O8vii 0.87 1.93 2.788 (2) 170
O8—H8⋯O6viii 0.85 1.88 2.698 (2) 164
O10—H10⋯O7iii 0.83 2.05 2.865 (2) 165
O9—H9⋯O8v 0.84 2.10 2.913 (2) 162
Symmetry codes: (iii) [x-{\script{1\over 2}}, -y+{\script{3\over 2}}, -z+1]; (v) [-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (vii) -x+2, [y+{\script{1\over 2}}], [-z+{\script{1\over 2}}]; (viii) x+1, y, z.

Polymorph (II)[link]

Crystal data
  • C6H12O5

  • Mr = 164.16

  • Orthorhombic, P 21 21 21

  • a = 6.0177 (2) Å

  • b = 6.4672 (2) Å

  • c = 18.0218 (7) Å

  • V = 701.37 (4) Å3

  • Z = 4

  • Dx = 1.555 Mg m−3

  • Mo Kα radiation

  • μ = 0.14 mm−1

  • T = 190 K

  • Hexagonal plate, colourless

  • 0.20 × 0.20 × 0.10 mm

Data collection
  • Nonius KappaCCD diffractometer

  • ω scans

  • Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]) Tmin = 0.865, Tmax = 0.986

  • 3322 measured reflections

  • 949 independent reflections

  • 883 reflections with I > 2σ(I)

  • Rint = 0.023

  • θmax = 27.5°

Refinement
  • Refinement on F2

  • R[F2 > 2σ(F2)] = 0.027

  • wR(F2) = 0.066

  • S = 1.03

  • 949 reflections

  • 100 parameters

  • H-atom parameters constrained

  • w = 1/[σ2(F2) + (0.02P)2 + 0.2P], where P = [max(Fo2,0) + 2Fc2]/3

  • (Δ/σ)max < 0.001

  • Δρmax = 0.22 e Å−3

  • Δρmin = −0.19 e Å−3

Table 2
Hydrogen-bond geometry (Å, °) for polymorph (II)[link]

D—H⋯A D—H H⋯A DA D—H⋯A
O10—H10⋯O7iii 0.99 1.80 2.778 (2) 170
O7—H7⋯O10ii 0.90 1.90 2.791 (2) 172
O9—H9⋯O8v 0.91 1.88 2.786 (2) 174
O8—H8⋯O6vi 0.95 1.87 2.803 (2) 165
Symmetry codes: (ii) x, y+1, z; (iii) [x-{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]; (v) [-x+2, y-{\script{1\over 2}}, -z+{\script{1\over 2}}]; (vi) x+1, y, z.

In the absence of significant anomalous scattering, Friedel pairs were merged and the absolute configuration assigned from the starting materials. The relatively large ratio of minimum to maximum corrections applied in the multi-scan process (1:1.19 and 1:1.14) include factors in addition to absorption, which were taken into account (Görbitz, 1999[Görbitz, C. H. (1999). Acta Cryst. B55, 1090-1098.]) by the multi-scan inter-frame scaling (DENZO/SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]). H atoms were all located in a difference map, but those attached to C atoms were repositioned geometrically. H atoms were initially refined with soft restraints on the bond lengths and angles to regularize their geometry (C—H = 0.93–0.98 Å and O—H = 0.82 Å) and Uiso(H) values (in the range 1.2–1.5 times Ueq of the parent atom), after which the positions were refined with riding constraints.

For both compounds, data collection: COLLECT (Nonius, 2001[Nonius (2001). COLLECT. Nonius BV, Delft, The Netherlands.]); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994[Altomare, A., Cascarano, G., Giacovazzo, G., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435.]); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003[Betteridge, P. W., Carruthers, J. R., Cooper, R. I., Prout, K. & Watkin, D. J. (2003). J. Appl. Cryst. 36, 1487.]); molecular graphics: CAMERON (Watkin et al., 1996[Watkin, D. J., Prout, C. K. & Pearce, L. J. (1996). CAMERON. Chemical Crystallography Laboratory, Oxford, England.]); software used to prepare material for publication: CRYSTALS.

Supporting information


Comment top

The properties of 1-deoxy ketohexose sugars have been little studied. The crystal structure of 1-deoxy-D-sorbose has recently been published (Jones et al., 2006) and as part of extending the range of simple monosaccharide derivatives, 1-deoxy-D-tagatose, (2), was synthesized. 1-Deoxy-D-tagatose has previously been synthesized (Wolfrom & Bennett, 1965; Dills & Covey, 1981; Cubero & Poza, 1985), but no crystal structure has been reported.

The demand for the large-scale production of rare sugars by biotechnological (Izumori, 2002, 2006; 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 themselves, however, 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.

1-Deoxy-D-tagatose, (2), was synthesized from protected D-lyxono-1,4-lactone, (1), by methylation using methyl lithium and subsequent deprotection with dowex resin (H+) (Jones et al., 2007). The deoxy sugar was readily crystallized and the present paper firmly establishes that, as for 1-deoxy-D-sorbose (Jones et al., 2006), 1-deoxy-D-tagatose exists in the crystalline state as the α-anomer of the pyranose ring form (3), in a chair conformation. Two polymorphic forms were observed to crystallize from the same mother liquor but at different rates. The two forms were needles and hexagonal plates. The hexagonal plates were found to crystallize out after 16 h, whereas the needles were only observed after 72 h. In both polymorphic forms, the title compound was in the α-pyranose form (3). In contrast, in aqueous solution it exists as an equilibrium mixture of the open chain, (2), α-pyranose, (3), α-furanose, (4), β-pyranose, (5) and β-furanose, (6), forms.

Crystals of two distinctly different habits, needles and plates, were observed in approximately equal quantities in the mother liquor. Cell parameters were determined for both forms and found to be different. Full data collections and structure solutions were performed on a sample of each habit. With the exception of the hydroxyl H atoms, the molecules were essentially identical (Figs. 1 and 2), with an r.m.s displacement between equivalent atoms of 0.05 Å after superposing one molecule on the other.

The formation of two different polymorphs of a material simultaneously in the same environment is termed `concomitant polymorphism' (Bernstein et al., 1995). There seems to be some uncertainly about the frequency of occurrence of this phenomenon. Bernstein et al. (1995) remark that it is rarely reported in the recent literature, but that it had been widely observed (von Groth et al., 1906) before the advent of X-ray crystallography. Perhaps this is because the thrust of many structure determinations has been focused on the molecular structure rather than the crystal structure, so that the work was performed on the first good quality crystal obtained rather than on a survey of a whole batch of material. Bowes et al. (2003) support this; 'Our identification, essentially by chance, of four such examples within a rather short space of time suggests to us that the phenomenon of concomitant polymorphism may, in fact, be a rather common one, certainly far more common than the current literature tends to suggest, but one which goes largely unnoticed.' In recent years the current authors have analysed almost 100 saccharide derivatives and this is the first one where polymorphism was clearly evident.

The different polymorphs arise from differences in the hydrogen-bonding network (Fig. 3 and 4). The most densely packed molecules occur in the plate-like crystals. As is usual in P212121, the molecules are linked into hydrogen-bonded helices around the twofold screw axes. The relationship between the two polymorphs is most easily visualized by concentrating on the helices containing O7 and O10. In the more dense polymorph, this is a helix involving four molecules. One turn consists of the sequence O7—H7···O10—H10···O7—H7···O10—H10···O7. In projection along the a axis, the four O atoms form an approximate square (Fig. 4). In the less dense polymorph, the helix is expanded to contain contributions from six molecules. Atom O10 still donates to O7, but atom O7 is now linked via atoms O8 and O9 back to an equivalent molecule that uses atom O10. One turn of this extended sequence contains O10—H10···O7—H7···O8···H9—O9 and the same pattern repeated by symmetry (Fig. 3). In the plate-like crystal, molecules 1 and 2 lie more or less side by side. In the needle-shaped crystals they are displaced with respect to each other so that the cross section of the helix becomes oval. Other O—H···O hydrogen bonds cross-link these helices. There are no unusually short inter-molecular contacts.

In summary 1-deoxy-D-tagatose, (2), exists in the crystalline state as 1-deoxy-α-D-tagatopyranose, (3); the absolute configuration is determined by the use of D-lyxono-1,4-lactone as the starting material. The X-ray crystal structure determined the stereochemistry at the anomeric position as being α, with the hydroxyl group in the axial position. 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.

The crystallographic interest in these materials arises from the concomitant polymorphism, few cases of which are reported in the literature, but which may eventually be of use for the fine-tuning of structure prediction programs.

Experimental top

The title compound was recrystallized from a mixture of ethyl acetate and methanol to give colourless crystals. [α]D22 −13 (c 2.0, H2O). The melting points of the two crystalline forms were found to be different (needles 409–411 K; hexagonal plate 416–418 K).

Refinement top

In the absence of significant anomalous scattering, Friedel pairs were merged and the absolute configuration assigned from the starting materials.

The relatively large ratio of minimum to maximum corrections applied in the multiscan process (1:1.19 and 1:1.14) include factors in additon to absorption, which were taken into account (Görbitz, 1999) by the multi-scan inter-frame scaling (DENZO/SCALEPACK; Otwinowski & Minor, 1997).

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, and O—H = 0.82 Å) and Uiso(H) (in the range 1.2–1.5 times Ueq of the parent atom), after which the positions were refined with riding constraints.

Computing details top

For both compounds, data collection: COLLECT (Nonius, 1997-2001).; 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.

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
Fig. 1.

The title compound from the needle crystals, with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitary radii.

Fig. 2.

The title compound from the hexagonal plate crystals, with displacement ellipsoids drawn at the 50% probability level. H atoms are shown as spheres of arbitary radii.

Fig. 3.

Part of the three-dimensional hydrogen-bonding network in the needle crystals, viewed approximately parallel to a and showing one turn of the helix (starting from the molecule with symmetry code ii). Molecules labelled 1 and 2 are described in the text. [Symmetry codes: (i) x, y − 1, z; (ii) x − 1/2, 1/2 − y, 1 − z; (iii) x − 1/2, 3/2 − y, 1 − z; (iv) x + 1/2, 1/2 − y, 1 − z; (v) 2 − x, y − 1/2, 1/2 − z; (vi) 3/2 − x, 1 − y, z + 1/2.]

Fig. 4.

The equivalent part of the three-dimensional hydrogen-bonding network in the plate crystals, viewed approximately parallel to a and showing one turn of the helix (starting from the molecule with symmetry code i). In strict a axis projection, the sides of the helix form an almost square lozenge. Molecules labelled 1 and 2 are described in the text. [Symmetry codes: (i) x − 1, y, z; (ii) x, y + 1, z; (iii) x − 1/2, 1/2 − y, 1 − z; (iv) x − 1/2, 3/2 − y, 1 − z.]
(I) 1-deoxy-α-D-tagatopyranose top
Crystal data top
C6H12O5Dx = 1.510 Mg m3
Mr = 164.16Melting point: 410 K
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 950 reflections
a = 6.0243 (2) Åθ = 5–27°
b = 7.5022 (3) ŵ = 0.13 mm1
c = 15.9717 (8) ÅT = 190 K
V = 721.85 (5) Å3Needle, colourless
Z = 40.40 × 0.10 × 0.10 mm
F(000) = 352
Data collection top
Nonius KappaCCD
diffractometer
879 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.057
ω scansθmax = 27.5°, θmin = 5.1°
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
h = 77
Tmin = 0.829, Tmax = 0.987k = 99
5125 measured reflectionsl = 2020
975 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.029H-atom parameters constrained
wR(F2) = 0.069 w = 1/[σ2(F2) + (0.03P)2 + 0.18P],
where P = [max(Fo2,0) + 2Fc2]/3
S = 1.01(Δ/σ)max = 0.000221
975 reflectionsΔρmax = 0.21 e Å3
100 parametersΔρmin = 0.19 e Å3
0 restraints
Crystal data top
C6H12O5V = 721.85 (5) Å3
Mr = 164.16Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 6.0243 (2) ŵ = 0.13 mm1
b = 7.5022 (3) ÅT = 190 K
c = 15.9717 (8) Å0.40 × 0.10 × 0.10 mm
Data collection top
Nonius KappaCCD
diffractometer
975 independent reflections
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
879 reflections with I > 2σ(I)
Tmin = 0.829, Tmax = 0.987Rint = 0.057
5125 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0290 restraints
wR(F2) = 0.069H-atom parameters constrained
S = 1.01Δρmax = 0.21 e Å3
975 reflectionsΔρmin = 0.19 e Å3
100 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.5929 (3)0.4965 (2)0.42010 (11)0.0191
C20.7853 (3)0.4814 (2)0.35731 (10)0.0195
C30.9254 (3)0.6509 (2)0.35894 (10)0.0178
C40.7820 (3)0.8125 (2)0.34139 (10)0.0178
C50.5824 (3)0.8149 (2)0.39944 (11)0.0203
O60.46117 (19)0.64971 (16)0.39797 (7)0.0196
O70.9050 (2)0.97311 (16)0.35788 (7)0.0241
O81.10068 (18)0.64141 (17)0.29777 (7)0.0225
O90.6941 (2)0.45542 (16)0.27647 (7)0.0257
O100.6906 (2)0.52030 (17)0.49875 (7)0.0226
C110.4368 (3)0.3392 (2)0.41843 (12)0.0265
H210.87700.37590.37410.0245*
H310.99070.66350.41660.0193*
H410.73540.80960.28220.0211*
H510.63320.83760.45730.0244*
H520.48080.90860.37930.0259*
H1110.32080.35880.45970.0410*
H1120.52050.23370.43250.0410*
H1130.37710.32620.36130.0410*
H70.91571.01610.30770.0373*
H81.22300.62780.32290.0338*
H100.59590.50590.53620.0370*
H90.77100.38220.24910.0404*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0156 (8)0.0213 (9)0.0206 (8)0.0002 (7)0.0020 (7)0.0016 (7)
C20.0175 (8)0.0221 (9)0.0190 (8)0.0027 (8)0.0034 (7)0.0019 (7)
C30.0149 (8)0.0245 (9)0.0141 (7)0.0003 (8)0.0008 (7)0.0019 (8)
C40.0171 (8)0.0200 (9)0.0162 (7)0.0018 (7)0.0003 (7)0.0005 (6)
C50.0194 (8)0.0185 (9)0.0230 (8)0.0013 (8)0.0021 (7)0.0011 (7)
O60.0137 (5)0.0204 (6)0.0247 (6)0.0001 (5)0.0007 (5)0.0015 (5)
O70.0274 (7)0.0241 (7)0.0209 (6)0.0067 (6)0.0014 (6)0.0027 (5)
O80.0135 (6)0.0350 (7)0.0190 (6)0.0028 (6)0.0016 (5)0.0009 (6)
O90.0241 (6)0.0324 (7)0.0206 (6)0.0006 (7)0.0025 (5)0.0104 (5)
O100.0202 (6)0.0305 (7)0.0172 (6)0.0018 (6)0.0014 (5)0.0025 (5)
C110.0245 (9)0.0240 (10)0.0310 (9)0.0036 (9)0.0016 (8)0.0023 (8)
Geometric parameters (Å, º) top
C1—C21.537 (2)C4—H410.986
C1—O61.441 (2)C5—O61.439 (2)
C1—O101.399 (2)C5—H510.988
C1—C111.509 (2)C5—H520.986
C2—C31.527 (2)O7—H70.867
C2—O91.417 (2)O8—H80.845
C2—H211.002O9—H90.841
C3—C41.515 (2)O10—H100.834
C3—O81.4402 (18)C11—H1110.972
C3—H311.006C11—H1120.965
C4—C51.519 (2)C11—H1130.986
C4—O71.438 (2)
C2—C1—O6108.31 (13)C3—C4—H41108.8
C2—C1—O10106.15 (13)C5—C4—H41111.1
O6—C1—O10110.50 (14)O7—C4—H41109.9
C2—C1—C11113.62 (14)C4—C5—O6112.44 (13)
O6—C1—C11106.04 (13)C4—C5—H51109.1
O10—C1—C11112.20 (13)O6—C5—H51108.7
C1—C2—C3110.14 (13)C4—C5—H52107.5
C1—C2—O9108.20 (14)O6—C5—H52107.1
C3—C2—O9110.15 (13)H51—C5—H52112.0
C1—C2—H21107.5C1—O6—C5113.81 (11)
C3—C2—H21110.4C4—O7—H7100.4
O9—C2—H21110.4C3—O8—H8108.9
C2—C3—C4110.39 (13)C2—O9—H9110.5
C2—C3—O8110.63 (13)C1—O10—H10109.9
C4—C3—O8109.40 (13)C1—C11—H111108.5
C2—C3—H31108.0C1—C11—H112108.2
C4—C3—H31108.5H111—C11—H112109.9
O8—C3—H31109.9C1—C11—H113108.7
C3—C4—C5110.37 (13)H111—C11—H113112.4
C3—C4—O7110.05 (12)H112—C11—H113109.0
C5—C4—O7106.62 (13)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O7—H7···O8i0.871.932.788 (2)170
O8—H8···O6ii0.851.882.698 (2)164
O10—H10···O7iii0.832.052.865 (2)165
O9—H9···O8iv0.842.102.913 (2)162
Symmetry codes: (i) x+2, y+1/2, z+1/2; (ii) x+1, y, z; (iii) x1/2, y+3/2, z+1; (iv) x+2, y1/2, z+1/2.
(II) 1-deoxy-α-D-tagatopyranose top
Crystal data top
C6H12O5Dx = 1.555 Mg m3
Mr = 164.16Melting point: 417 K
Orthorhombic, P212121Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2ac 2abCell parameters from 826 reflections
a = 6.0177 (2) Åθ = 5–27°
b = 6.4672 (2) ŵ = 0.14 mm1
c = 18.0218 (7) ÅT = 190 K
V = 701.37 (4) Å3Hexagonal plate, colourless
Z = 40.20 × 0.20 × 0.10 mm
F(000) = 352
Data collection top
Nonius KappaCCD
diffractometer
883 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
ω scansθmax = 27.5°, θmin = 5.2°
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
h = 77
Tmin = 0.865, Tmax = 0.986k = 88
3322 measured reflectionsl = 2223
949 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.027H-atom parameters constrained
wR(F2) = 0.066 w = 1/[σ2(F2) + (0.02P)2 + 0.2P],
where P = [max(Fo2,0) + 2Fc2]/3
S = 1.03(Δ/σ)max = 0.000232
949 reflectionsΔρmax = 0.22 e Å3
100 parametersΔρmin = 0.19 e Å3
19 restraints
Crystal data top
C6H12O5V = 701.37 (4) Å3
Mr = 164.16Z = 4
Orthorhombic, P212121Mo Kα radiation
a = 6.0177 (2) ŵ = 0.14 mm1
b = 6.4672 (2) ÅT = 190 K
c = 18.0218 (7) Å0.20 × 0.20 × 0.10 mm
Data collection top
Nonius KappaCCD
diffractometer
949 independent reflections
Absorption correction: multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
883 reflections with I > 2σ(I)
Tmin = 0.865, Tmax = 0.986Rint = 0.023
3322 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02719 restraints
wR(F2) = 0.066H-atom parameters constrained
S = 1.03Δρmax = 0.22 e Å3
949 reflectionsΔρmin = 0.19 e Å3
100 parameters
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
C10.7170 (3)0.0840 (2)0.38341 (8)0.0164
C20.9081 (3)0.1432 (2)0.33058 (8)0.0159
C31.0591 (3)0.3034 (2)0.36665 (8)0.0148
C40.9243 (3)0.4903 (2)0.39003 (8)0.0151
C50.7330 (3)0.4220 (3)0.43951 (9)0.0185
O60.59682 (19)0.26528 (17)0.40555 (6)0.0173
O71.06403 (19)0.62698 (18)0.43249 (6)0.0200
O81.23071 (18)0.36448 (18)0.31620 (6)0.0195
O90.8191 (2)0.22943 (18)0.26426 (6)0.0214
O100.81963 (19)0.00833 (17)0.44640 (6)0.0179
C110.5454 (3)0.0585 (3)0.34920 (9)0.0212
H210.99700.01700.31840.0180*
H311.12830.24090.41180.0171*
H410.86530.56350.34530.0179*
H510.63840.54490.45100.0218*
H520.79610.36500.48660.0218*
H1110.42760.08980.38670.0249*
H1120.47660.01010.30510.0249*
H1130.61870.19000.33340.0249*
H100.71350.04650.48580.0500*
H70.99760.75060.43590.0500*
H90.79610.11610.23580.0500*
H81.36990.34530.34050.0500*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0162 (8)0.0155 (7)0.0176 (7)0.0038 (7)0.0010 (6)0.0004 (7)
C20.0173 (8)0.0156 (7)0.0146 (7)0.0040 (7)0.0002 (6)0.0005 (6)
C30.0129 (8)0.0172 (7)0.0143 (6)0.0023 (7)0.0005 (6)0.0029 (6)
C40.0152 (7)0.0144 (7)0.0159 (7)0.0005 (7)0.0024 (6)0.0002 (6)
C50.0188 (8)0.0168 (7)0.0198 (7)0.0009 (7)0.0031 (7)0.0032 (7)
O60.0139 (6)0.0156 (5)0.0224 (5)0.0012 (5)0.0001 (5)0.0028 (5)
O70.0212 (6)0.0151 (5)0.0237 (5)0.0004 (6)0.0043 (5)0.0013 (5)
O80.0149 (6)0.0231 (6)0.0207 (5)0.0016 (5)0.0032 (5)0.0050 (5)
O90.0286 (7)0.0209 (5)0.0147 (5)0.0007 (6)0.0058 (5)0.0009 (5)
O100.0175 (6)0.0193 (5)0.0170 (5)0.0008 (5)0.0008 (5)0.0042 (5)
C110.0184 (8)0.0187 (8)0.0266 (8)0.0007 (7)0.0020 (7)0.0029 (7)
Geometric parameters (Å, º) top
C1—C21.542 (2)C4—H411.000
C1—O61.4339 (18)C5—O61.4399 (19)
C1—O101.4239 (18)C5—H511.000
C1—C111.515 (2)C5—H521.000
C2—C31.523 (2)O7—H70.896
C2—O91.4235 (17)O8—H80.953
C2—H211.000O9—H90.906
C3—C41.515 (2)O10—H100.986
C3—O81.4316 (18)C11—H1111.000
C3—H311.000C11—H1121.000
C4—C51.522 (2)C11—H1131.000
C4—O71.4400 (18)
C2—C1—O6110.20 (12)C3—C4—H41110.1
C2—C1—O10105.83 (12)C5—C4—H41109.9
O6—C1—O10109.87 (11)O7—C4—H41110.2
C2—C1—C11114.10 (13)C4—C5—O6112.70 (12)
O6—C1—C11105.48 (12)C4—C5—H51108.8
O10—C1—C11111.39 (13)O6—C5—H51108.9
C1—C2—C3110.50 (12)C4—C5—H52108.5
C1—C2—O9109.56 (12)O6—C5—H52108.5
C3—C2—O9108.45 (12)H51—C5—H52109.5
C1—C2—H21109.4C5—O6—C1113.98 (12)
C3—C2—H21109.3C4—O7—H7108.9
O9—C2—H21109.7C3—O8—H8107.9
C2—C3—C4110.00 (13)C2—O9—H9102.5
C2—C3—O8110.30 (12)C1—O10—H10113.5
C4—C3—O8110.01 (12)C1—C11—H111109.3
C2—C3—H31108.7C1—C11—H112109.6
C4—C3—H31108.6H111—C11—H112109.5
O8—C3—H31109.1C1—C11—H113109.4
C3—C4—C5109.63 (12)H111—C11—H113109.5
C3—C4—O7108.98 (12)H112—C11—H113109.5
C5—C4—O7107.97 (12)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O10—H10···O7i0.991.802.778 (2)170
O7—H7···O10ii0.901.902.791 (2)172
O9—H9···O8iii0.911.882.786 (2)174
O8—H8···O6iv0.951.872.803 (2)165
Symmetry codes: (i) x1/2, y+1/2, z+1; (ii) x, y+1, z; (iii) x+2, y1/2, z+1/2; (iv) x+1, y, z.

Experimental details

(I)(II)
Crystal data
Chemical formulaC6H12O5C6H12O5
Mr164.16164.16
Crystal system, space groupOrthorhombic, P212121Orthorhombic, P212121
Temperature (K)190190
a, b, c (Å)6.0243 (2), 7.5022 (3), 15.9717 (8)6.0177 (2), 6.4672 (2), 18.0218 (7)
V3)721.85 (5)701.37 (4)
Z44
Radiation typeMo KαMo Kα
µ (mm1)0.130.14
Crystal size (mm)0.40 × 0.10 × 0.100.20 × 0.20 × 0.10
Data collection
DiffractometerNonius KappaCCD
diffractometer
Nonius KappaCCD
diffractometer
Absorption correctionMulti-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
Multi-scan
(DENZO/SCALEPACK; Otwinowski & Minor, 1997)
Tmin, Tmax0.829, 0.9870.865, 0.986
No. of measured, independent and
observed [I > 2σ(I)] reflections
5125, 975, 879 3322, 949, 883
Rint0.0570.023
(sin θ/λ)max1)0.6490.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.029, 0.069, 1.01 0.027, 0.066, 1.03
No. of reflections975949
No. of parameters100100
No. of restraints019
H-atom treatmentH-atom parameters constrainedH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.21, 0.190.22, 0.19

Computer programs: COLLECT (Nonius, 1997-2001)., DENZO/SCALEPACK (Otwinowski & Minor, 1997), DENZO/SCALEPACK, SIR92 (Altomare et al., 1994), CRYSTALS (Betteridge et al., 2003), CAMERON (Watkin et al., 1996), CRYSTALS.

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
O7—H7···O8i0.871.932.788 (2)170
O8—H8···O6ii0.851.882.698 (2)164
O10—H10···O7iii0.832.052.865 (2)165
O9—H9···O8iv0.842.102.913 (2)162
Symmetry codes: (i) x+2, y+1/2, z+1/2; (ii) x+1, y, z; (iii) x1/2, y+3/2, z+1; (iv) x+2, y1/2, z+1/2.
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
O10—H10···O7i0.991.802.778 (2)170
O7—H7···O10ii0.901.902.791 (2)172
O9—H9···O8iii0.911.882.786 (2)174
O8—H8···O6iv0.951.872.803 (2)165
Symmetry codes: (i) x1/2, y+1/2, z+1; (ii) x, y+1, z; (iii) x+2, y1/2, z+1/2; (iv) x+1, y, z.
 

Acknowledgements

Financial support (to RS), provided through the European Community's Human Potential Programme under contract HPRN-CT-2002-00173, is gratefully acknowledged.

References

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