4-[(2-Hydroxyethyl)-iminomethyl]-5-hydroxymethyl-2-methylpyridin-3-ol

Article abstract of DOI:10.1107/S0108270107046574

The title compound, C10H14N2O3, is a Schiff base which is derived from pyridoxal and represents, therefore, a vitamin B6-related compound. Mol-ecules are linked into sheets by a combination of O - H...O and O - H...N hydrogen bonds. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107046574

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
hydroxymethyl group is nearly coplanar with the pyridine ring,
with a C3ÐC4ÐC8ÐO2 torsion angle of 176.28 (8)ꢀ. The
same holds for the enamine group, with a C2ÐC3ÐC7ÐN2
torsion angle of 0.9 (1)ꢀ. Atom N2 is bonded to the O1ÐH1
group via a hydrogen bridge (Table 2), forming an intra-
molecular six-membered pseudo-ring. The 2-hydroxyethyl
ISSN 0108-2701
4-[(2-Hydroxyethyl)iminomethyl]-5-
hydroxymethyl-2-methylpyridin-3-ol
Uwe Bohme* and Betty Gunther
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È
Institut fur Anorganische Chemie, Technische Universitat Bergakademie Freiberg,
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È
Leipziger Strasse 29, 09596 Freiberg, Germany
Correspondence e-mail: uwe.boehme@chemie.tu-freiberg.de
Received 3 September 2007
Accepted 21 September 2007
Online 13 October 2007
Figure 1
The molecular structure of (I), drawn with 50% probability displacement
ellipsoids.
The title compound, C10H14N2O3, is a Schiff base which is
derived from pyridoxal and represents, therefore, a vitamin
B6-related compound. Molecules are linked into sheets by a
combination of OÐHÁ Á ÁO and OÐHÁ Á ÁN hydrogen bonds.
Comment
Vitamin B6 is an essential cofactor to a large number of
enzymes that catalyse many reactions of amino acids (Sykes et
al., 1991). One of the active forms of vitamin B6 is the
heterocyclic aldehyde pyridoxal. Much attention has been
focused on the coordination chemistry of pyridoxal Schiff
bases with amino acids (Christensen, 1957; Long et al., 1980;
Dawes et al., 1982; Walz et al., 1983; Rao et al. 1985; Astheimer
et al. 1985; Sykes et al. 1991; Costa Pessoa et al., 1999). No
X-ray structure of a free pyridoxal Schiff base has been
reported to date, since the Schiff base ligand is usually
generated in the coordination sphere of the transition metal.
This approach is impractical for complexation with moisture-
sensitive reagents, for instance, halogenosilanes or organo-
metallic derivatives. The title compound, (I), was prepared in
order to supply an alternative ligand system for the prepara-
tion of vitamin B6±Schiff base complexes. Fig. 1 shows the
molecular structure of (I) and the atomic labelling scheme.
Selected bond lengths are listed in Table 1.
Figure 2
Head-to-tail dimers of (I), formed by O3ÐH3Á Á ÁN1A hydrogen bonds
and ꢀ±ꢀ interactions. [Symmetry code: (ii) x ‡ 1; y; z ‡ 12.]
The substituted pyridine ring has bond lengths that differ
somewhat from those expected for an unsubstituted pyridine
ring owing to the irregular substitution pattern of the pyri-
doxal ring. The enamine group (N2 C7) has a bond length of
Figure 3
The packing of (I) in the c direction, showing the sheet structure which is
build up by intermolecular hydrogen bridges between the dimers. (The
lower part of the hydrogen-bridged dimers is shown shaded and H atoms
have been omitted for clarity.)
Ê
1.280 (1) A, which is typical for this type of Schiff base
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(Bohme & Gunther, 2006, 2007; Bohme et al., 2006). The
Acta Cryst. (2007). C63, o641±o642
DOI: 10.1107/S0108270107046574
# 2007 International Union of Crystallography o641

organic compounds
Table 1
Selected bond lengths (A).
group (C9/C10/O3) is rotated out of the molecular plane, with
an N2ÐC9ÐC10ÐO3 torsion angle of 74.5 (1)ꢀ. The O3ÐH3
group forms a hydrogen bridge with the pyridine N atom of
another molecule, giving pairs of molecules which are
connected `head-to-tail' (see Fig. 2). These pairs are further
stabilized by ꢀ±ꢀ interactions between ꢀ-conjugated units,
Ê
N1ÐC1
N1ÐC5
N2ÐC7
N2ÐC9
O1ÐC2
O2ÐC8
O3ÐC10
C1ÐC2
1.330 (1)
C1ÐC6
C2ÐC3
C3ÐC4
C3ÐC7
C4ÐC5
C4ÐC8
C9ÐC10
1.497 (1)
1.404 (1)
1.410 (1)
1.466 (1)
1.381 (1)
1.516 (1)
1.520 (2)
1.355 (1)
1.280 (1)
1.456 (1)
1.343 (1)
1.414 (1)
1.427 (1)
1.413 (1)
Ê
with a distance of 3.030 A between the planes formed by
atoms N1, C1±C8, N2 and O1. The crystal packing is further
stabilized by OÐHÁ Á ÁO hydrogen bonds, which generate a
sheet structure parallel to the crystallographic ab plane
(Fig. 3).
Compound (I) represents a potentially useful ligand for the
preparation of complexes with main group and transition
metals. Furthermore, the preparation of coordination poly-
mers seems to be feasible because of the presence of three OH
groups and two nitrogen-donor positions in the molecule.
Table 2
Hydrogen-bond geometry (A, ).
ꢀ
Ê
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
O1ÐH1Á Á ÁN2
O2ÐH2Á Á ÁO3i
O3ÐH3Á Á ÁN1ii
0.885 (17)
0.84
0.84
1.765 (16)
1.98
1.94
2.573 (1)
2.817 (1)
2.775 (1)
150.7 (15)
173
172
Symmetry codes: (i) x ‡ 12; y ‡ 21; z; (ii) x ‡ 1; y; z ‡ 21.
Experimental
Pyridoxal hydrochloride (4.07 g, 20 mmol) and sodium methanolate
(1.08 g, 20 mmol) were mixed in ethanol (200 ml). The suspension
was stirred at room temperature and treated with 2-aminoethanol
(1.22 g, 1.2 ml, 20 mmol). The reaction mixture was boiled at re¯ux
temperature for 2 h. After that time, a yellow solution and a white
precipitate were formed. The precipitate (NaCl) was ®ltered off and
washed with ethanol. The ®ltrate was reduced in a vacuum to 50 ml.
The product was precipitated by adding n-hexane (30 ml) and was
isolated by ®ltration (yield 3.6 g, 85.6%; m.p. 421 K). NMR (DMSO-
kUeq(carrier), where k = 1.5 for methyl and hydroxy groups, and k =
1.2 for all other H atoms.
Data collection: SMART (Bruker, 2004); cell re®nement: SAINT
(Bruker, 2004); data reduction: SAINT; program(s) used to solve
structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in
SHELXTL-Plus (Sheldrick, 1991); software used to prepare material
for publication: SHELXL97.
1
d6, 298 K, TMS): H ꢁ 2.37 (s, Me, H6), 3.70, 3.72 (2 Â t, CH2, H9,
H10), 4.64 (s, CH2, H8), 4.87 (s broad, O3ÐH3), 5.37 (s broad, O2Ð
H2), 7.86 (s, C5ÐH5), 8.86 (s, N C7ÐH7), 14.49 (s broad, O1ÐH1);
13C ꢁ 18.9 (C6), 58.5, 60.5, 60.9 (C8, C9, C10), 118.9, 132.9, 136.9,
148.8, 155.2 (C1±C5), 164.5 (C7).
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GD3146). Services for accessing these data are
described at the back of the journal.
References
Crystal data
3
Ê
C10H14N2O3
Mr = 210.23
V = 1955.99 (10) A
Z = 8
Astheimer, H., Nepveu, F., Walz, L. & Haase, W. (1985). J. Chem. Soc. Dalton
Trans. pp. 315±320.
Monoclinic, C2=c
Mo Kꢃ radiation
ꢄ = 0.11 mm
T = 153 (2) K
0.60 Â 0.16 Â 0.10 mm
È
È
Bohme, U. & Gunther, B. (2006). Acta Cryst. E62, m1711±m1712.
1
Ê
a = 16.2739 (5) A
È
È
Bohme, U. & Gunther, B. (2007). Inorg. Chem. Commun. 10, 482±484.
Bohme, U., Wiesner, S. & Gunther, B. (2006). Inorg. Chem. Commun. 9, 806±
Ê
b = 9.6403 (3) A
È
È
Ê
c = 13.5513 (4) A
809.
Bruker (2004). SMART (Version 5.628) and SAINT (Version 6.45a). Bruker
AXS Inc., Madison, Wisconsin, USA.
Christensen, H. N. (1957). J. Am. Chem. Soc. 79, 4073±4078.
Costa Pessoa, J., Cavaco, I., Correia, I., Duarte, M. T., Gillard, R. D.,
Henriques, R. T., Higes, F. J., Madeira, C. & Tomaz, I. (1999). Inorg. Chim.
Acta, 293, 1±11.
Dawes, H. M., Waters, J. M. & Waters, T. N. (1982). Inorg. Chim. Acta, 66, 29±
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Pradeep, C. P. (2005). Acta Cryst. E61, o3825±o3827.
Rao, S. P. S., Manohar, H. & Bau, R. (1985). J. Chem. Soc. Dalton Trans.
pp. 2051±2057.
ꢂ = 113.069 (2)ꢀ
Data collection
Bruker SMART CCD area-detector
diffractometer
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
Tmin = 0.935, Tmax = 0.989
16737 measured re¯ections
2858 independent re¯ections
2292 re¯ections with I > 2ꢅ(I)
Rint = 0.029
È
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Re®nement
R[F2 > 2ꢅ(F2)] = 0.038
wR(F2) = 0.109
S = 1.05
2858 re¯ections
140 parameters
H atoms treated by a mixture of
independent and constrained
re®nement
3
Ê
Áꢆmax = 0.46 e A
3
Ê
0.20 e A
Áꢆmin
=
Sheldrick, G. M. (1991). SHELXTL-Plus. Release 4.1. Siemens Analytical
X-ray Instruments Inc., Madison, Wisconsin, USA.
È
Sheldrick, G. M. (1996). SADABS. University of Gottingen, Germany.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
There are few structure reports of Schiff bases with oxygen in the
ortho position where the intramolecular bridging H atom is localized
at the N atom (e.g. Pradeep, 2005; Dubs et al., 2000; Hop¯ et al., 1998).
Therefore, atom H1 was located by difference Fourier synthesis and
re®ned without constraints. All other H atoms were placed in
geometrically idealized positions and treated as riding atoms, with
È
Gottingen, Germany.
Sykes, A. G., Larsen, R. D., Fischer, J. R. & Abbott, E. H. (1991). Inorg. Chem.
30, 2911±2916.
Walz, L., Paulus, H., Haase, W., Langhof, H. & Nepveu, F. (1983). J. Chem. Soc.
Dalton Trans. pp. 657±664.
Ê
CÐH = 0.95±0.99 A and OÐH = 0.84 A. For all H atoms, Uiso(H) =
Ê
ꢁ
o642 Bohme and Gunther C10H14N2O3
Acta Cryst. (2007). C63, o641±o642
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