C-H...π and π-π interactions in the supramolecular structure of 3-methyl-1,4-diphenyl-1H-pyrazolo[3,4-b]-pyridine

Article abstract of DOI:10.1107/S0108270102006340

The supramolecular structure of the compound, C₁₉H₁₅N₃, was investigated. The structure of the compound was defined by π-π-stacking and C-H···π interactions. The π-πstacking involved the pyridine ring of the pyrazolo-pyrid

Full text of DOI:10.1107/S0108270102006340

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
atomic numbering differs for (I) and (II); all values are quoted
with respect to the numbering of (I).
ISSN 0108-2701
CÐHÁ Á Áp and p±p interactions in the
supramolecular structure of 3-methyl-
1
,4-diphenyl-1H-pyrazolo[3,4-b]-
pyridine
a
b
b
John N. Low, * Justo Cobo, Manuel Nogueras, Adolfo
b
c
c
S a nchez, Harlen Torres and Braulio Insuasty
The torsion angles for the phenyl groups in (I) are given in
Table 1. As can be seen from the examples given below, the
conformations of the phenyl rings in compounds (I) and (II)
are very similar, for example, in the case of ring 4 (atoms C41±
C46) [values for (II) are given in parenthesis], C5ÐC4Ð
a
Department of Chemistry, University of Aberdeen, Meston Walk, Old Aberdeen
b
AB24 3UE, Scotland, Departamento de Qu Âõ mica Inorg a nica y Org a nica,
c
Universidad de Ja e n, 23071 Ja e n, Spain, and Grupo de Investigaci o n de
Compuestos Heteroc Âõ clicos, Departamento de Qu Âõ mica, Universidad del Valle,
AA25360 Cali, Colombia
ꢀ
ꢀ
ꢀ
Correspondence e-mail: jnlow111@hotmail.com
C41ÐC42 = 112.8 (2) [118.2 (5) ], but differ by nearly 23 in
the case of phenyl ring 3 (atoms C11±C16), where C7aÐN1Ð
Received 4 April 2002
Accepted 9 April 2002
Online 30 April 2002
ꢀ
ꢀ
C11ÐC12 = 135.2 (2) [158.0 (5) ].
In (I), the ꢀ±ꢀ stacking involves the pyridine ring of the
pyrazolo±pyridine group. The ring in the molecule at (x, y, z)
stacks above the ring at (� x, 2 � y, 1 � z) across the centre of
The supramolecular structure of the title compound,
C H N , is de®ned by ꢀ±ꢀ-stacking and CÐHÁ Á Áꢀ interac-
1
2
Ê
inversion at (0,1, ), with a distance of 3.563 (2) A between the
1
9
15
3
ring centroids, a perpendicular distance between the rings of
Ê Ê
.443 (2) A and a centroid offset of 0.913 (2) A (Fig. 2a).
tions. There are no conventional hydrogen bonds in the
structure.
3
Although compound (II) does contain a conventional NÐ
Comment
Previously, we have reported different syntheses of biologi-
cally active compounds with a pyrazolo[3,4-b]pyridine
skeleton. 5-Aminopyrazoles were used as starting materials
with ꢁ,ꢂ-unsaturated ketones, as shown in the Scheme
(
2
Quiroga, Insuasty, Cruz et al., 1998; Quiroga, Cruz et al.,
001), with benzaldehydes and Meldrum's acid (Quiroga,
Hormaza et al., 1998; Quiroga, Insuasty, Hormaza et al., 1998)
or with dimedone (Quiroga, Mej õÂ a et al., 2001) as reactants. We
now report the crystal structure of fully aromatized 3-methyl-
1
,4-diphenyl-1H-pyrazolo[3,4-b]pyridine, (I), which was pre-
pared to test the synthetic application of 5-(3-aryl-2-pro-
penylidene)-2,2-dimethyl-1,3-dioxane-4,6-diones [the struct-
ures of some examples have been reported recently; see, for
example, Low et al. (2002)]. Reaction of the phenyl derivative
with 5-amino-3-methyl-1-phenylpyrazole yielded (I). In this
reaction, the Meldrum's acid fragment was completely elimi-
nated, resulting in a fully aromatized product.
The pyrazole and pyridine rings in (I) are planar within
experimental error and have a dihedral angle between them of
ꢀ
5
.13 (10) . The only other compound with a similar pyrazolo±
pyridine structure reported in the Cambridge Structural
Database (CSD; Version 5.22 of October 2001; Allen &
Kennard, 1993) is 6-amino-5-cyano-3-methyl-1,4-diphenyl-
pyrazolo[3,4-b]pyridine (Quiroga et al., 1999), (II), which
Figure 1
View of (I) with the atomic numbering scheme. Displacement ellipsoids
are plotted at the 30% probability level.
crystallizes in space group P2 /n. In (II), the dihedral angle
1
ꢀ
between the pyrazole and pyridine rings is 3.6 (3) . N.B. The
o298 # 2002 International Union of Crystallography
DOI: 10.1107/S0108270102006340
Acta Cryst. (2002). C58, o298±o300

organic compounds
HÁ Á ÁN hydrogen bond, there is similar ꢀ±ꢀ stacking between
the pyridine rings related by the centre of inversion at (0,1,1),
Ê
with a CgÁ Á ÁCg distance of 3.701 (3) A, a perpendicular
Ê
distance of 3.552 A and an offset between the centres of
Ê
.04 A. Fig. 2(b) shows the stacking in (II), labelled in this case
1
with the numbering system used for (I). Figs. 2(a) and 2(b)
show the differences in the stacking in the two compounds.
These differences result from the different polarizations of the
pyridine rings in the two compounds, which result from the
presence of the amino and cyano substituents in compound
(
II).
There are two CÐHÁ Á Áꢀ interactions involving each of
phenyl rings 3 (atoms C11±C16, centroid Cg3) and 4 (atoms
ii
C41±C46, centroid Cg4). The C43ÐH43Á Á ÁCg3 interaction
(
dimers via the centre of inversion at ( , , ) [symmetry code:
Table 2) links the molecules into centrosymmetrically related
1
1 1
2 2
2
Figure 3
View of the linked dimer chains and sheet formed by the ꢀ±ꢀ stacking
in (I).
(
ii) 1 � x, 1 � y, 1 � z]. These dimers are then linked by a
i
C13ÐH13Á Á ÁCg4 interaction and the equivalent interaction
1
1
via the centre at ( , ,0), so forming chains of dimers running
2
2
parallel to [001] [symmetry code: (i) x, y, � 1 + z]. These CÐ
HÁ Á Áꢀ and ꢀ±ꢀ interactions link the molecules into two-
dimensional sheets lying parallel to (110) (Fig. 3). In (II), the
equivalent ring to ring 3 is involved in a CÐHÁ Á Áꢀ interaction.
In this case, the atom equivalent to H42 is involved in an
1
1
3
interaction with the ring in the molecule at ( � x, + y, � z),
2
2
2
Ê
with an HÁ Á ÁCg distance of 2.85 A, a CÁ Á ÁCg distance of
Ê
ꢀ
.735 (5) A and an angle at H of 160 .
3
Experimental
An ethanol solution containing equimolar quantities of 5-(3-phenyl-
2-propenylidene)-2,2-dimethyl-[1,3]dioxane-4,6-dione and 5-amino-
3-methyl-1-phenylpyrazole in ethanol was heated under re¯ux for
Figure 2
View of the ꢀ±ꢀ stacking between the molecules in (a) (I) and (b) (II).
ꢁ
Acta Cryst. (2002). C58, o298±o300
John N. Low et al.
C H N
19 15 3
o299

organic compounds
2 h. The solvent was then removed under vacuum and the resulting
crude solid was puri®ed by silica-gel column chromatography using
Compound (I) crystallized in the triclinic system; space group P1
was assumed and con®rmed by the analysis. H atoms were treated as
Ê
riding, with CÐH distances of 0.95 (aromatic) and 0.98 A (methyl).
hexane/ethyl acetate (1:1 v/v) as eluant, yielding (I) (55%, m.p.
requires:
408 K). Analysis, found: C 79.9, H 5.2, N 14.7%; C19
H
15
N
3
Data collection: KappaCCD Server Software (Nonius, 1997); cell
re®nement: DENZO±SMN (Otwinowski & Minor, 1997); data
reduction: DENZO±SMN; program(s) used to solve structure:
SHELXS97 (Sheldrick, 1997); program(s) used to re®ne structure:
SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPII
(Johnson, 1976) and PLATON (Spek, 2002); software used to
prepare material for publication: SHELXL97 and WordPerfect
macro PRPKAPPA (Ferguson, 1999).
C 80.0, H 5.3, N 14.7%. Crystals suitable for single-crystal X-ray
diffraction analysis were obtained from a chloroform solution.
Crystal data
C
19
H
15
N
3
Z = 2
= 1.319 Mg m
Mo Kꢁ radiation
�
3
M
r
= 285.34
Triclinic, P1
D
x
Ê
a = 8.1392 (4) A
Cell parameters from 3135
re¯ections
Ê
b = 8.4351 (4) A
Ê
c = 11.3852 (6) A
ꢀ
ꢄ = 3.1±27.4
X-ray data were collected at the EPSRC, X-ray Crystal-
lographic Service, University of Southampton. The authors
thank the staff for all their help and advice. JNL thanks NCR
Self-Service, Dundee, for grants which have provided
computing facilities for this work. MN, AS and JC thank the
ꢀ
ꢀ
ꢀ
� 1
ꢁ
= 77.951 (3)
ꢅ = 0.08 mm
T = 120 (1) K
ꢂ = 81.192 (2)
ꢃ = 70.681 (2)
Ê
V = 718.39 (6) A
Block, yellow
0.20 Â 0.10 Â 0.10 mm
3
Data collection
`
Ministerio de Educaci o n, Cultura y Deportes (Programa de
Nonius KappaCCD diffractometer
1682 re¯ections with I > 2ꢇ(I)
Cooperaci o n con Iberoamerica, AECI)' of Spain for ®nancial
support of part of this work
'
scans, and ! scans with ꢆ offsets
Absorption correction: multi-scan
DENZO±SMN; Otwinowski &
Minor, 1997)
min = 0.944, Tmax = 0.994
Rint = 0.092
ꢀ
ꢄ
max = 27.4
(
h = � 10 ! 10
k = � 10 ! 10
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GD1203). Services for accessing these data are
described at the back of the journal.
T
l = � 14 ! 14
9
3
243 measured re¯ections
135 independent re¯ections
Intensity decay: negligible
Re®nement
References
2
Re®nement on F
2
H-atom parameters constrained
2
2
2
2
R[F > 2ꢇ(F )] = 0.053
wR(F ) = 0.123
S = 0.94
w = 1/[ꢇ (F
where P = (F
(Á/ꢇ)max < 0.001
Áꢈmax = 0.23 e A
Áꢈmin = � 0.35 e AÊ
o
) + (0.0455P) ]
Allen, F. H. & Kennard, O. (1993). Chem. Des. Autom. News, 8, 1, 31±37.
Ferguson, G. (1999). PRPKAPPA. University of Guelph, Canada.
Johnson, C. K. (1976). ORTEPII. Report ORNL-5138. Oak Ridge National
Laboratory, Tennessee, USA.
2
2
2
o
+ 2F
c
)/3
Ê
� 3
3
2
135 re¯ections
00 parameters
� 3
Low, J. N., Cobo, J., Nogueras, M., S a nchez, A., Insuasty, B. & Torres, H.
(
2002). Acta Cryst. C58, o39±o41.
Nonius (1997). KappaCCD Server Software. Windows 3.11 Version. Nonius
BV, Delft, The Netherlands.
Table 1
Selected torsion angles ( ).
ꢀ
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.
Quiroga, J., Alvarado, M., Insuasty, B., Moreno, R., Ravina, E., Estevez, I. &
de Almedia, R. H. (1999). J. Heterocycl. Chem. 36, 1311±1316.
Quiroga, J., Cruz, S., Insuasty, B., Abon õ a, R., Cobo, J., S a nchez, A., Nogueras,
M. & Low, J. N. (2001). J. Heterocycl. Chem. 38, 53±60.
Quiroga, J., Hormaza, A., Insuasty, B. & M a rquez, M. (1998). J. Heterocycl.
Chem. 35, 409±412.
Quiroga, J., Insuasty, B., Cruz, S., Hern a ndez, P., Bola nÄ os, A., Moreno, R.,
Hormaza, A. & de Almedia, R. H. (1998). J. Heterocycl. Chem. 35, 333±338.
Quiroga, J., Insuasty, B., Hormaza, A., Cabildo, P., Claramunt, R. M. &
Elguero, J. (1998). J. Heterocycl. Commun. 5, 115±122.
C7aÐN1ÐC11ÐC12
N2ÐN1ÐC11ÐC12
C7aÐN1ÐC11ÐC16
N2ÐN1ÐC11ÐC16
135.2 (2)
C5ÐC4ÐC41ÐC46
� 66.5 (3)
111.6 (2)
112.8 (2)
� 69.1 (3)
� 39.0 (3)
� 45.1 (3)
140.78 (18)
C3aÐC4ÐC41ÐC46
C5ÐC4ÐC41ÐC42
C3aÐC4ÐC41ÐC42
Table 2
Hydrogen-bonding geometry (A, ).
Ê
ꢀ
Cg3 and Cg4 are the centroids of the C11±C16 and C41±C46 rings,
respectively.
Quiroga, J., Mej Âõ a, D., Insuasty, B., Abon õ a, R., Nogueras, M., S a nchez, A. &
Cobo, J. (2001). Tetrahedron, 57, 6947±6953.
Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of
G oÈ ttingen, Germany.
Spek, A. L. (2002). PLATON. March 2002 Version. University of Utrecht, The
Netherlands.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
i
C13ÐH13Á Á ÁCg4
0.95
0.95
2.74
2.79
3.543 (3)
3.579 (3)
142
142
ii
C43ÐH43Á Á ÁCg3
Symmetry codes: (i) x; y; z � 1; (ii) 1 � x; 1 � y; 1 � z.
ꢁ
o300 John N. Low et al.
C H N
19 15 3
Acta Cryst. (2002). C58, o298±o300