2 Bromo­ethyl 2,3,4,6 tetra O acetyl β D gluco­pyran­oside

organic papers

o2644

16H23BrO10 doi:10.1107/S1600536805022555 Acta Cryst.(2005). E61, o2644–o2645

Acta Crystallographica Section E Structure Reports

Online

ISSN 1600-5368

2-Bromoethyl 2,3,4,6-tetra-

O

-acetyl-b-

-gluco-pyranoside

Ivan Halasz,a* Renata Odzˇak,a Srdanka Tomic´aand Dubravka Matkovic´-Cˇ alogovic´b

a_{Laboratory of Organic Chemistry, Department}

of Chemistry, Faculty of Science, University of Zagreb, Strossmayerov trg 14, 10000 Zagreb, Croatia, andb_{Laboratory of General and} Inorganic Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zvonimirova 8, 10002 Zagreb, Croatia

Correspondence e-mail: ihalasz@chem.pmf.hr

Key indicators

Single-crystal X-ray study

T= 295 K

Mean(C–C) = 0.006 A˚

Rfactor = 0.047

wRfactor = 0.142

Data-to-parameter ratio = 15.6

For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.

#2005 International Union of Crystallography Printed in Great Britain – all rights reserved

The six-membered ring of the title compound, C16H23BrO10, adopts a chair conformation. The molecules are intercon-nected by weak C—H O hydrogen bonds into a three-dimensional network.

Comment

The synthesis of oligosaccharides has played an important role in the development of carbohydrate chemistry. Today, many different procedures are known, and these are constantly being improved and further developed (Lindhorst, 2003). Neighbouring-group participation has frequently been used in organic synthesis. In carbohydrate chemistry, it is generally thought that glycosyl donors possessing anO-acyl group with a participating function at C2 give exclusively the corresponding 1,2-trans-glycoside with quite high stereoselectivity in glycosylation reactions. In our investigations of mono-saccharides, the OAc group was used as the protective group for further glycosylation reactions. The 1-OAc group in the glycosyl donor was transformed to a good leaving group using activated BF3Et2O. Thus, we synthesized the title compound, (I), and determined its crystal structure.

The six-membered ring of (I) adopts a chair conformation (Fig. 1). The absolute configuration, known from the synthetic pathway, is fully confirmed by refinement of the Flack para-meter (Flack & Bernardinelli, 2000).

Since all its hydroxyl groups are either acylated or alkyl-ated, compound (I) has many possible hydrogen-bond acceptors and, at the same time, no hydrogen-bond donors other than C—H groups. A number of possible weak hydrogen bonds can be found, but only those which satisfy the usual geometrical conditions are listed in Table 1. Six C—H O hydrogen bonds are intermolecular and form a three-dimen-sional network. Among these, four link the molecules along thebaxis, whereas the other two link the molecules along the

aandcaxes. It is interesting to note that only acetyl O atoms and the anomeric O atom are involved in hydrogen bonding in (I), even though, in general, the ester O atom is known to be involved in hydrogen bonding in small organic molecules (Molcˇanov et al., 2004). The reason for this could be steric hindrance of the ester O atoms in the crystal structure of (I).

The packing of compound (I) is different from that observed in (2-ethyl)-2,3,4,6-tetra-O-acetyl--d

-glucopyrano-side [Cambridge Structural Database (Allen, 2002; version 5.26) refcode ZETNOB (Prawat et al., 1995)]. The Br atom itself forms no contacts other than those of a van der Waals nature. It can be speculated that the differences in packing arise from the larger radius of the Br atom and its effect on the H-atom donor properties of the methylene group to which it is bonded. The C—H group of this methylene group is involved in the shortest hydrogen bond in the crystal structure of (I), whereas in ZETNOB it forms no hydrogen bonds.

Experimental

The title compound was synthesized according to the method of Dahme´net al.(1983).1H and13C NMR spectra are in agreement with data presented by Lindhorst (2003).

Crystal data

C16H23BrO10 Mr= 455.25

Monoclinic,P21 a= 9.4153 (12) A˚ b= 9.8326 (14) A˚ c= 11.2069 (19) A˚

= 96.391 (12) V= 1031.1 (3) A˚3 Z= 2

Dx= 1.466 Mg m

3

MoKradiation Cell parameters from 2233

reflections

= 2.8–18.3 = 2.04 mm1 T= 295 (2) K Prism, colourless 0.450.100.08 mm

Data collection

Oxford Xcalibur 3 CCD area-detector diffractometer

!scans

Absorption correction: analytical

3873 independent reflections 3044 reflections withI> 2(I) Rint= 0.040

max= 26.1

Refinement

Refinement onF2 R[F2_{> 2(F}2_{)] = 0.047} wR(F2) = 0.142 S= 1.03 3873 reflections 249 parameters

H-atom parameters constrained w= 1/[2

(Fo2) + (0.0929P)2]

whereP= (Fo2+ 2Fc2)/3

(/)max= 0.001

max= 0.39 e A˚3

min=0.58 e A˚3 Absolute structure: Flack &

Bernardinelli (2000), with 1722 Friedel pairs

Flack parameter = 0.005 (13)

Table 1

Hydrogen-bonding geometry (A˚ ,_).

D—H A D—H H A D A D—H A

C1—H1 O5i

0.98 2.55 3.479 (6) 157

C6—H6B O9i

0.97 2.73 3.697 (6) 173

C10—H10B O9i 0.96 2.63 3.497 (8) 154 C8—H8A O7ii

0.96 2.60 3.459 (8) 149

C12—H12C O1iii

0.96 2.66 3.581 (6) 158

C16—H16B O3iv

0.97 2.45 3.367 (7) 157

Symmetry codes: (i) 2x;y1

2;1z; (ii) 2x; 1

2þy;1z; (iii) 1þx;y;z; (iv)

x;y;z1.

Methine and methylene H atoms were positioned geometrically, with C—H = 0.98 A˚ andUiso(H) = 1.2Ueq(C) for methine H, and C— H = 0.97 A˚ andUiso(H) = 1.2Ueq(C) for methylene H atoms. Methyl H atoms were refined using a riding model, with C—H = 0.98 A˚ and

Uiso(H) = 1.5Ueq(C).

Data collection: CrysAlisCCD (Oxford Diffraction, 2003); cell refinement:CrysAlisRED(Oxford Diffraction, 2003); data reduction:

CrysAlisRED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure:SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication:SHELXL97.

The authors thank the Ministry of Science, Education and Sports of the Republic of Croatia for financial support (grant Nos. 119632 and 119610).

References

Alcock, N. W. (1970).Crystallographic Computing, edited by F. R. Ahmed, S. R. Hall & C. P. Huber, p. 271. Copenhagen: Munksgaard.

Allen, F. H. (2002).Acta Cryst.B58, 380–388.

Dahme´n, J., Frejd, T., Gro¨nberg, G., Lave, T., Magnusson, G. & Noori, G. (1983).Carbohydr. Res.116, 303–307.

Farrugia, L. J. (1997).J. Appl. Cryst.30, 565.

Flack, H. D. & Bernardinelli, G. (2000).J. Appl. Cryst.33, 1143–1148. Lindhorst, T. K. (2003).Essentials of Carbohydrate Chemistry and

Biochem-istry, 2nd edition, revised and updated. Weinheim: Wiley–VCH Verlag. Molcˇanov, K., Kojic´-Prodic´, B. & Raos, N. (2004).Acta Cryst.B60, 424–432. Oxford Diffraction (2003). CrysAlisCCD and CrysAlisRED. Versions

1.171.26 beta. Oxford Diffraction Ltd, Abingdon, England.

Prawat, H., Mahidol, C., Ruchirawat, S., Prawat, U., Tuntiwachwuttikul, P., Tooptakong, U., Taylor, W. C., Pakawatchai, C., Skelton, B. W. & White, Figure 1

supporting information

sup-1

Acta Cryst. (2005). E61, o2644–o2645

supporting information

Acta Cryst. (2005). E61, o2644–o2645 [https://doi.org/10.1107/S1600536805022555]

2-Bromoethyl 2,3,4,6-tetra-

O

-acetyl-β-

-glucopyranoside

Ivan Halasz, Renata Od

ž

ak, Srdanka Tomi

ć

and Dubravka Matkovi

ć

-

Č

alogovi

ć

2-Bromoethyl 2,3,4,6-tetra-O-acetyl-β-D-glucopyranoside

Crystal data

C16H23BrO10

Mr = 455.25 Monoclinic, P21

Hall symbol: P 2yb

a = 9.4153 (12) Å

b = 9.8326 (14) Å

c = 11.2069 (19) Å

β = 96.391 (12)°

V = 1031.1 (3) Å3

Z = 2

F(000) = 468

Dx = 1.466 Mg m−3

Mo Kα radiation, λ = 0.71073 Å Cell parameters from 2233 reflections

θ = 2.8–18.3°

µ = 2.04 mm−1

T = 295 K

Prismatic, colourless 0.45 × 0.10 × 0.08 mm

Data collection

Oxford Xcalibur 3 CCD area-detector diffractometer

Radiation source: fine-focus sealed tube Graphite monochromator

ω scans

Absorption correction: analytical (Alcock, 1970)

Tmin = 0.686, Tmax = 0.871

13961 measured reflections 3873 independent reflections 3044 reflections with I > 2σ(I)

Rint = 0.040

θmax = 26.1°, θmin = 3.6°

h = −11→11

k = −12→11

l = −13→13

Refinement

Refinement on F2

Least-squares matrix: full

R[F2 _{> 2σ(F}2_{)] = 0.047}

wR(F2_{) = 0.142}

S = 1.03 3873 reflections 249 parameters 1 restraint

Primary atom site location: structure-invariant direct methods

Secondary atom site location: difference Fourier map

Hydrogen site location: inferred from neighbouring sites

H-atom parameters constrained

w = 1/[σ2_(F

o2) + (0.0929P)2]

where P = (Fo2 + 2Fc2)/3

(Δ/σ)max = 0.001

Δρmax = 0.39 e Å−3

Δρmin = −0.58 e Å−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F2 _{against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F}2_,

conventional R-factors R are based on F, with F set to zero for negative F2_{. The threshold expression of F}2 _{> σ(F}2_{) is used}

only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2

are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2₎

x y z Uiso*/Ueq

Br 0.44532 (6) 0.87439 (9) 0.10552 (6) 0.0997 (3)

O1 0.7903 (3) 0.7113 (3) 0.4259 (2) 0.0461 (6)

O4 1.1191 (3) 0.6509 (3) 0.6177 (2) 0.0455 (6)

O6 1.2101 (3) 0.8151 (3) 0.4228 (2) 0.0407 (6)

O8 1.0379 (3) 0.7442 (3) 0.2001 (2) 0.0473 (7)

O10 0.7438 (3) 0.7440 (3) 0.2230 (2) 0.0483 (7)

C1 0.8439 (4) 0.6935 (4) 0.3131 (3) 0.0428 (9)

H1 0.8612 0.5968 0.2993 0.051*

C2 0.9815 (4) 0.7729 (4) 0.3119 (3) 0.0378 (8)

H2 0.9637 0.8705 0.3195 0.045*

C3 1.0884 (4) 0.7245 (4) 0.4132 (3) 0.0382 (8)

H3 1.1198 0.6324 0.3955 0.046*

C5 0.8828 (4) 0.6483 (4) 0.5194 (3) 0.0420 (8)

H5 0.8994 0.5540 0.4963 0.050*

C4 1.0243 (4) 0.7236 (4) 0.5307 (3) 0.0390 (8)

H4 1.0113 0.8169 0.5580 0.047*

C15 0.6246 (5) 0.6522 (6) 0.1936 (4) 0.0580 (11)

H15A 0.5650 0.6497 0.2588 0.070*

H15B 0.6593 0.5610 0.1812 0.070*

C6 0.8085 (5) 0.6476 (5) 0.6302 (4) 0.0535 (10)

H6A 0.7121 0.6128 0.6119 0.064*

H6B 0.8592 0.5889 0.6902 0.064*

C7 0.7320 (5) 0.8035 (6) 0.7730 (4) 0.0601 (12)

O7 1.3641 (3) 0.6423 (4) 0.4314 (4) 0.0809 (11)

C13 1.0254 (5) 0.8379 (5) 0.1129 (4) 0.0528 (11)

C12 1.4549 (4) 0.8683 (7) 0.4627 (5) 0.0712 (13)

H12C 1.5477 0.8270 0.4768 0.107*

H12B 1.4361 0.9191 0.5324 0.107*

H12A 1.4523 0.9283 0.3949 0.107*

C9 1.2020 (5) 0.7217 (5) 0.7020 (4) 0.0550 (10)

O5 1.1933 (5) 0.8428 (4) 0.7112 (4) 0.0947 (14)

C16 0.5404 (5) 0.7028 (6) 0.0816 (4) 0.0676 (13)

H16A 0.4692 0.6353 0.0535 0.081*

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Acta Cryst. (2005). E61, o2644–o2645

O2 0.8040 (3) 0.7848 (3) 0.6761 (2) 0.0544 (7)

C11 1.3429 (4) 0.7591 (5) 0.4376 (4) 0.0490 (10)

C10 1.3017 (5) 0.6327 (7) 0.7772 (4) 0.0733 (14)

H10A 1.3574 0.5807 0.7268 0.110*

H10B 1.2484 0.5721 0.8226 0.110*

H10C 1.3642 0.6873 0.8312 0.110*

C14 1.0672 (6) 0.7818 (7) −0.0004 (4) 0.0768 (15)

H14A 0.9949 0.7199 −0.0344 0.115*

H14B 1.1564 0.7344 0.0155 0.115*

H14C 1.0774 0.8546 −0.0558 0.115*

O3 0.6779 (6) 0.7089 (6) 0.8173 (4) 0.1114 (18)

C8 0.7405 (9) 0.9464 (7) 0.8188 (6) 0.094 (2)

H8A 0.6789 1.0035 0.7663 0.141*

H8B 0.8371 0.9784 0.8215 0.141*

H8C 0.7109 0.9491 0.8981 0.141*

Atomic displacement parameters (Å2₎

U11 _U22 _U33 _U12 _U13 _U23

Geometric parameters (Å, º)

Br—C16 1.943 (6) C6—H6A 0.9700

O1—C1 1.422 (5) C6—H6B 0.9700

O1—C5 1.427 (5) C7—O3 1.194 (7)

O4—C9 1.350 (5) C7—O2 1.356 (5)

O4—C4 1.436 (4) C7—C8 1.495 (9)

O6—C11 1.360 (5) O7—C11 1.169 (6)

O6—C3 1.446 (4) C13—O9 1.191 (6)

O8—C13 1.338 (5) C13—C14 1.477 (7)

O8—C2 1.443 (4) C12—C11 1.510 (7)

O10—C1 1.394 (5) C12—H12C 0.9600

O10—C15 1.449 (5) C12—H12B 0.9600

C1—C2 1.514 (5) C12—H12A 0.9600

C1—H1 0.9800 C9—O5 1.199 (6)

C2—C3 1.507 (5) C9—C10 1.478 (7)

C2—H2 0.9800 C16—H16A 0.9700

C3—C4 1.508 (5) C16—H16B 0.9700

C3—H3 0.9800 C10—H10A 0.9600

C5—C6 1.492 (5) C10—H10B 0.9600

C5—C4 1.517 (5) C10—H10C 0.9600

C5—H5 0.9800 C14—H14A 0.9600

C4—H4 0.9800 C14—H14B 0.9600

C15—C16 1.494 (7) C14—H14C 0.9600

C15—H15A 0.9700 C8—H8A 0.9600

C15—H15B 0.9700 C8—H8B 0.9600

C6—O2 1.446 (6) C8—H8C 0.9600

C1—O1—C5 110.6 (3) C5—C6—H6B 109.9

C9—O4—C4 119.1 (3) H6A—C6—H6B 108.3

C11—O6—C3 118.0 (3) O3—C7—O2 120.1 (5)

C13—O8—C2 119.3 (3) O3—C7—C8 126.8 (5)

C1—O10—C15 112.8 (3) O2—C7—C8 113.0 (4)

O10—C1—O1 108.8 (3) O9—C13—O8 122.9 (4)

O10—C1—C2 108.7 (3) O9—C13—C14 126.1 (5)

O1—C1—C2 109.4 (3) O8—C13—C14 111.1 (4)

O10—C1—H1 110.0 C11—C12—H12C 109.5

O1—C1—H1 110.0 C11—C12—H12B 109.5

C2—C1—H1 110.0 H12C—C12—H12B 109.5

O8—C2—C3 108.3 (3) C11—C12—H12A 109.5

O8—C2—C1 107.8 (3) H12C—C12—H12A 109.5

C3—C2—C1 109.3 (3) H12B—C12—H12A 109.5

O8—C2—H2 110.5 O5—C9—O4 122.2 (4)

C3—C2—H2 110.5 O5—C9—C10 125.8 (5)

C1—C2—H2 110.5 O4—C9—C10 112.0 (4)

O6—C3—C2 108.6 (3) C15—C16—Br 112.5 (4)

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Acta Cryst. (2005). E61, o2644–o2645

O6—C3—H3 109.3 C15—C16—H16B 109.1

C2—C3—H3 109.3 Br—C16—H16B 109.1

C4—C3—H3 109.3 H16A—C16—H16B 107.8

O1—C5—C6 108.0 (3) C7—O2—C6 116.6 (4)

O1—C5—C4 107.9 (3) O7—C11—O6 123.5 (4)

C6—C5—C4 114.9 (3) O7—C11—C12 126.1 (4)

O1—C5—H5 108.6 O6—C11—C12 110.4 (4)

C6—C5—H5 108.6 C9—C10—H10A 109.5

C4—C5—H5 108.6 C9—C10—H10B 109.5

O4—C4—C3 108.5 (3) H10A—C10—H10B 109.5

O4—C4—C5 106.7 (3) C9—C10—H10C 109.5

C3—C4—C5 111.3 (3) H10A—C10—H10C 109.5

O4—C4—H4 110.1 H10B—C10—H10C 109.5

C3—C4—H4 110.1 C13—C14—H14A 109.5

C5—C4—H4 110.1 C13—C14—H14B 109.5

O10—C15—C16 108.0 (4) H14A—C14—H14B 109.5

O10—C15—H15A 110.1 C13—C14—H14C 109.5

C16—C15—H15A 110.1 H14A—C14—H14C 109.5

O10—C15—H15B 110.1 H14B—C14—H14C 109.5

C16—C15—H15B 110.1 C7—C8—H8A 109.5

H15A—C15—H15B 108.4 C7—C8—H8B 109.5

O2—C6—C5 109.1 (3) H8A—C8—H8B 109.5

O2—C6—H6A 109.9 C7—C8—H8C 109.5

C5—C6—H6A 109.9 H8A—C8—H8C 109.5

O2—C6—H6B 109.9 H8B—C8—H8C 109.5

Hydrogen-bond geometry (Å, º)

D—H···A D—H H···A D···A D—H···A

C1—H1···O5i _{0.98 2.55 3.479 (6) 157}

C6—H6B···O9i _{0.97 2.73 3.697 (6) 173}

C10—H10B···O9i _{0.96 2.63 3.497 (8) 154}

C8—H8A···O7ii _{0.96 2.60 3.459 (8) 149}

C12—H12C···O1iii _{0.96 2.66 3.581 (6) 158}

C16—H16B···O3iv _{0.97 2.45 3.367 (7) 157}