Three substituted 4-pyrazolylbenzoates: Hydrogen-bonded supramolecular structures in one, two and three dimensions

Article abstract of DOI:10.1107/S0108270106050360

The molecules of ethyl 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoate, C ₁₃H₁₅N₃O₂, are linked by two independent N - H...-O hydrogen bonds into a chain of edge-fused and alternating R₄²(8) a

Full text of DOI:10.1107/S0108270106050360

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
respectively. The principal points of interest in the structures
of compounds (I)±(III) are the different modes of supra-
molecular aggregation, leading to hydrogen-bonded structures
in one, two and three dimensions, respectively.
ISSN 0108-2701
Three substituted 4-pyrazolylbenzo-
ates: hydrogen-bonded supramol-
ecular structures in one, two and
three dimensions
Jaime Portilla,a Ernesto G. Mata,b Manuel Nogueras,c
Justo Cobo,c John N. Lowd and Christopher Glidewelle*
a
Â
Â
Â
Grupo de Investigacion de Compuestos Heterocõclicos, Departamento de Quõmica,
Universidad de Valle, AA 25360 Cali, Colombia, bCONICET±Facultad de Ciencias
Â
Â
Bioquõmicas y Farmaceuticas, Universidad Nacional de Rosario, Rosario, Suipacha
The supramolecular structure of compound (I) is simple.
Amino atom N45 in the molecule at (x, y, z) acts as a
hydrogen-bond donor, via H45A and H45B, to the O11 atoms
c
Â
Â
Â
531, S2002LRK, Argentina, Departamento de Quõmica Inorganica y Organica,
Universidad de Jaen, 23071 Jaen, Spain, dDepartment of Chemistry, University of
Aberdeen, Meston Walk, Old Aberdeen AB24 3UE, Scotland, and eSchool of
Chemistry, University of St Andrews, Fife KY16 9ST, Scotland
Correspondence e-mail: cg@st-andrews.ac.uk
Â
Â
in the molecules at ( x, 1
y, 1
z) and (x, y, 1 + z),
respectively (Table 1). Propagation by translation and inver-
sion of these two hydrogen bonds then generates a chain of
edge-fused centrosymmetric rings running parallel to the [001]
direction, with R22(20) (Bernstein et al., 1995) rings centred at
(0, 12, n + 21 ) (where n represents zero or an integer), and R24(8)
rings centred at (0, 12, n) (n = zero or integer) (Fig. 4). There are
no direction-speci®c interactions between adjacent chains; in
particular CÐHÁ Á Áꢀ(arene) hydrogen bonds and aromatic
ꢀ±ꢀ stacking interactions are both absent.
Received 15 November 2006
Accepted 22 November 2006
Online 12 December 2006
The molecules of ethyl 4-(5-amino-3-methyl-1H-pyrazol-1-
yl)benzoate, C13H15N3O2, are linked by two independent NÐ
HÁ Á ÁO hydrogen bonds into a chain of edge-fused and
alternating R24(8) and R22(20) rings. A combination of NÐ
HÁ Á ÁN and NÐHÁ Á ÁO hydrogen bonds links the molecules
of methyl 4-(5-amino-3-tert-butyl-1H-pyrazol-1-yl)benzoate,
C15H19N3O2, into sheets of alternating R22(20) and R66(32)
rings. In 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoic acid
monohydrate, C11H11N3O2ÁH2O, the molecular components
are linked into a three-dimensional framework structure by a
combination of ®ve independent hydrogen bonds, two of OÐ
HÁ Á ÁN type and one each of OÐHÁ Á ÁO, NÐHÁ Á ÁO and NÐ
HÁ Á ÁN types.
Comment
As precursors for the synthesis of pyrazolo[1,5-a][1,3,5]-
benzotriazepines, which are useful as drugs, agrochemicals and
dye intermediates (Tachibana & Kaneko, 1989), we have
synthesized several 4-(5-aminopyrazol-1-yl)benzoates by
construction of the pyrazole ring from 4-hydrazinobenzoic
acid and 3-aminocrotononitrile, and report here the structures
of three substituted 4-pyrazolylbenzoic acid derivatives,
namely ethyl 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoate,
(I), methyl 4-(5-amino-3-tert-butyl-1H-pyrazol-1-yl)benzoate,
(II), and 4-(5-amino-3-methyl-1H-pyrazol-1-yl)benzoic acid
monohydrate, (III) (Figs. 1±3).
The intramolecular geometries of compounds (I)±(III)
present no unexpected features; the pyrazole rings all exhibit
marked bond ®xation, and the dihedral angles between the
two rings in (I)±(III) are 30.1 (2), 34.2 (2) and 46.5 (2)ꢀ,
Figure 1
A molecule of (I), showing the atom-labelling scheme. Displacement
ellipsoids are drawn at the 30% probability level.
Acta Cryst. (2007). C63, o21±o25
DOI: 10.1107/S0108270106050360
# 2007 International Union of Crystallography o21

organic compounds
The molecules of compound (II) are linked by a combina-
tion of NÐHÁ Á ÁO and NÐHÁ Á ÁN hydrogen bonds (Table 2);
this may be contrasted with compound (I), where NÐHÁ Á ÁN
hydrogen bonds were absent. The molecules are linked into
sheets, and the formation of the sheet is readily analysed in
terms of a dimeric building block. Amino atom N45 in the
molecule at (x, y, z) acts as a hydrogen-bond donor, via H45A,
to atom O11 in the molecule at (1
x, 1
y, 1
z), so
generating by inversion a dimeric unit characterized by an
R22(20) motif. In addition, the N45 atoms in the molecules at (x,
y, z) and (1 x, 1 y, 1 z), which are components of the
R22(20) dimer centred at (12, 21, 12 ), act as hydrogen-bond donors,
via H45B, to the ring atoms N42 of the molecules at (1 x,
1
2
1
2
1
2
1
2
+ y,
z) and (x,
y, + z), respectively, which are
themselves components of the dimers centred at (12, 1, 0) and
Figure 2
A molecule of (II), showing the atom-labelling scheme. Displacement
ellipsoids are drawn at the 30% probability level.
Figure 4
A stereoview of part of the crystal structure of (I), showing the formation
of a chain of alternating R22(20) and R24(8) rings along [001]. For the sake
of clarity, H atoms bonded to C atoms have been omitted.
Figure 3
The independent molecular components of (III), showing the atom-
labelling scheme and the OÐHÁ Á ÁO hydrogen bond within the selected
asymmetric unit. Displacement ellipsoids are drawn at the 30%
probability level.
Figure 5
A stereoview of part of the crystal structure of (II), showing the
formation of a sheet of R22(20) and R66(32) rings parallel to (100). For the
sake of clarity, H atoms bonded to C atoms have been omitted.
ꢁ
o22 Portilla et al.
C13H15N3O2, C15H19N3O2 and C11H11N3O2ÁH2O
Acta Cryst. (2007). C63, o21±o25

organic compounds
(12, 0, 1). In a similar way, atoms N42 at (x, y, z) and (1 x,
y, 1 z) accept hydrogen bonds from atoms N45 in the
which involves the water molecule. In the ®rst substructure,
which runs parallel to the [100] direction, water atom O1 at (x,
y, z) acts as a hydrogen-bond donor, via H1A and H1B,
respectively, to atom N42 at ( x, 1 y, 1 z) and N45 at
(1 x, 1 y, 1 z). Propagation by inversion of these two
hydrogen bonds then generates a chain of edge-fused
centrosymmetric rings with R44(22) rings centred at (n, 21, 12) (n =
1
molecules at (1 x, 12 + y, 21 z) and (x, 23 y, 12 + z), which
are components of the dimers centred at (12, 0, 0) and (21, 1, 1)
respectively. Thus, each dimer is directly linked, via NÐHÁ Á ÁN
hydrogen bonds, to four adjacent dimers, and propagation of
this interaction by the space group leads to the formation of a
sheet parallel to (100) built from alternating R22(20) and R66(32)
rings, where both ring types are centrosymmetric (Fig. 5).
There are no direction-speci®c interactions between adjacent
sheets, nor is there any interweaving of adjacent sheets,
despite the occurrence of the large R66(32) rings; interweaving
is prevented by the effective masking of the large rings by
pairs of tert-butyl groups (Fig. 5).
Compound (III) is a stoichiometric monohydrate, and in the
selected asymmetric unit (Fig. 3), the components are linked
by a rather short and almost linear OÐHÁ Á ÁO hydrogen bond
(Table 3). Four further hydrogen bonds link the molecular
components into a single three-dimensional framework
structure, whose formation is readily analysed in terms of
three independent one-dimensional substructures, only one of
1
1 1
zero or integer) and R44(24) rings centred at (n + , , ) (n =
2
2 2
zero or integer) (Fig. 6).
The second substructure runs parallel to the [010] direction
and consists of simple chains built from the organic compo-
nent only; amino atom N45 at (x, y, z) acts as a hydrogen-bond
donor, via H45A, to ring atom N42 at (12 x, 21 + y, 21 z), so
forming a C(5) chain generated by the 21 screw axis along
(14, y, 14 ) (Fig. 7). The third substructure is also built from only
the organic components, and runs along the [101] direction;
amino atom N45 at (x, y, z) acts as a hydrogen-bond donor,
3
2
1
2
this time via H45B, to atom O11 at (12 + x,
y,
+ z), so
forming a C(10) chain generated by the n-glide plane at y = 43
(Fig. 8). The combination of the chains along [100], [010] and
[101] suf®ces to link all the molecules into a single three-
dimensional framework structure.
Thus, rather modest changes in the peripheral substituents
in compounds (I)±(III) are associated with substantial changes
both in the patterns of the hydrogen bonds deployed and in
the dimensionality of the resulting supramolecular structures.
Figure 6
A stereoview of part of the crystal structure of (III), showing the
formation of a chain of alternating R44(22) and R44(24) rings along [100].
For the sake of clarity, H atoms bonded to C atoms have been omitted.
Figure 7
Part of the crystal structure of (III), showing the formation of a C(5)
Figure 8
Part of the crystal structure of (III), showing the formation of a C(10)
chain along [101]. For the sake of clarity, the water molecule and H atoms
bonded to C atoms have been omitted. Atoms marked with an asterisk
(*) or a hash (#) are at the symmetry positions (12 + x, 23 y, 21 + z) and
chain along [010]. For the sake of clarity, water molecules and H atoms
bonded to C atoms have been omitted. Atoms marked with an asterisk
1
2
(*) or a hash (#) are at the symmetry positions (12 x, 21 + y,
z) and
1
1
1
2
3
(
x,
+ y, 12 z), respectively.
(
+ x,
2
y, 12 + z), respectively.
2
2
ꢁ
Acta Cryst. (2007). C63, o21±o25
Portilla et al.
C13H15N3O2, C15H19N3O2 and C11H11N3O2ÁH2O o23

organic compounds
Table 1
Hydrogen-bond geometry (A, ) for (I).
Experimental
ꢀ
Ê
For the synthesis of compounds (I) and (III), 3-aminocrotononitrile
(3.3 mmol) was added at ambient temperature to a stirred solution of
4-hydrazinobenzoic acid (3.3 mmol) in ethanol (6 ml). The resulting
suspension was stirred for 20 min and then 5 M HCl solution (15 ml)
was added. The mixture was stirred for 40 min at 368 K and, after
cooling (< 263 K), the solution was made either basic or neutral, in
separate experiments, using aqueous ammonia solution. From the
basic solution, compound (I) was precipitated upon removal of the
solvent; compound (I) was collected by ®ltration and recrystallized
from dimethyl sulfoxide to give yellow crystals suitable for single-
crystal X-ray diffraction (yield 13%, m.p. 430±431 K). MS (70 eV)
m/z (%): 245 (100, M+), 217 (21), 200 (39), 134 (11), 122 (26). From
the neutral solution, compound (III) was precipitated upon removal
of the solvent; the compound was collected by ®ltration and recrys-
tallized from ethanol to give yellow crystals suitable for single-crystal
X-ray diffraction (yield 72%, m.p. 503±504 K). MS (70 eV) m/z (%):
217 (100, M+), 200 (28). For the synthesis of compound (II), 4,4-
dimethyl-3-oxopentanenitrile (3.3 mmol) was added at ambient
temperature to a stirred solution of 4-hydrazinobenzoic acid
(3.3 mmol) in methanol (6 ml). The resulting suspension was stirred
for 20 min and then 5 M HCl solution (15 ml) was added. The mixture
was stirred for 40 min at 368 K and, after cooling (< 263 K), the
mixture was neutralized using aqueous ammonia solution. The
intermediate 4-(5-amino-3-tert-butyl-1H-pyrazol-1-yl)benzoic acid
was precipitated as a yellow solid (yield 80%, m.p. 468±469 K). A
suspension of the entire batch of this intermediate in methanol (6 ml)
was treated with diazomethane (3.3 mmol) at 273±283 K. Compound
(II) was formed as a yellow solid, which was collected by ®ltration and
then recrystallized from methanol to afford yellow crystals suitable
for single-crystal X-ray diffraction (overall yield 76%, m.p. 468±
469 K). MS (70 eV) m/z (%): 273 (53, M+), 258 (100), 231 (83).
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
N45ÐH45AÁ Á ÁO11i
0.94
0.94
2.30
2.11
3.1190 (19)
3.0252 (18)
146
165
N45ÐH45BÁ Á ÁO11ii
Symmetry codes: (i) x; y ‡ 1; z ‡ 1; (ii) x; y; z ‡ 1.
Compound (II)
Crystal data
C15H19N3O2
Mr = 273.33
Monoclinic, P21=c
Ê
a = 6.1272 (2) A
b = 11.6374 (3) A
Ê
c = 20.3182 (7) A
ꢂ = 98.629 (2)ꢀ
V = 1432.38 (8) A
Z = 4
Dx = 1.267 Mg m
Mo Kꢁ radiation
ꢄ = 0.09 mm
T = 120 (2) K
Lath, yellow
0.48 Â 0.22 Â 0.12 mm
3
1
Ê
3
Ê
Data collection
Bruker±Nonius KappaCCD
diffractometer
' and ! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.971, Tmax = 0.990
24177 measured re¯ections
3269 independent re¯ections
2353 re¯ections with I > 2ꢅ(I)
Rint = 0.050
ꢆmax = 27.5ꢀ
Re®nement
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.042
wR(F2) = 0.112
S = 1.03
3269 re¯ections
w = 1/[ꢅ2(F2o) + (0.0591P)2
+ 0.2591P]
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max < 0.001
3
Ê
Áꢇmax = 0.17 e A
3
Ê
0.34 e A
185 parameters
H-atom parameters constrained
Áꢇmin
=
Compound (I)
Table 2
Hydrogen-bond geometry (A, ) for (II).
ꢀ
Ê
Crystal data
C13H15N3O2
Mr = 245.28
Triclinic, P1
a = 7.2228 (4) A
Ê
b = 8.4433 (3) A
c = 10.5938 (5) A
ꢁ = 98.234 (3)ꢀ
ꢂ = 107.609 (2)ꢀ
ꢃ = 97.907 (3)ꢀ
Z = 2
Dx = 1.362 Mg m
Mo Kꢁ radiation
ꢄ = 0.10 mm
T = 120 (2) K
Plate, yellow
0.28 Â 0.14 Â 0.06 mm
3
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
N45ÐH45AÁ Á ÁO11i
0.93
0.92
2.22
2.34
3.1388 (16)
3.2386 (17)
172
166
1
Ê
N45ÐH45BÁ Á ÁN42ii
Symmetry codes: (i) x ‡ 1; y ‡ 1; z ‡ 1; (ii) x ‡ 1; y ‡ 12; z ‡ 21.
Ê
3
Ê
V = 598.12 (5) A
Compound (III)
Data collection
Crystal data
Bruker±Nonius KappaCCD
diffractometer
' and ! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.979, Tmax = 0.994
12140 measured re¯ections
2748 independent re¯ections
1904 re¯ections with I > 2ꢅ(I)
Rint = 0.052
ꢆmax = 27.6ꢀ
C11H11N3O2ÁH2O
Z = 4
Dx = 1.400 Mg m
Mo Kꢁ radiation
ꢄ = 0.10 mm
T = 120 (2) K
3
Mr = 235.24
Monoclinic, P21=n
1
Ê
a = 8.0166 (2) A
Ê
b = 7.5082 (2) A
Ê
c = 18.5507 (5) A
Block, yellow
0.54 Â 0.36 Â 0.18 mm
ꢂ = 91.8140 (16)ꢀ
3
Ê
V = 1116.01 (5) A
Re®nement
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.049
wR(F2) = 0.136
S = 1.08
2748 re¯ections
165 parameters
H-atom parameters
constrained
w = 1/[ꢅ2(F2o) + (0.0676P)2
+ 0.0939P]
Data collection
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max = 0.001
Bruker±Nonius KappaCCD
diffractometer
' and ! scans
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
Tmin = 0.961, Tmax = 0.982
11603 measured re¯ections
2551 independent re¯ections
2037 re¯ections with I > 2ꢅ(I)
Rint = 0.031
3
Ê
Áꢇmax = 0.23 e A
3
Ê
0.32 e A
Áꢇmin
=
ꢆmax = 27.5ꢀ
ꢁ
o24 Portilla et al.
C13H15N3O2, C15H19N3O2 and C11H11N3O2ÁH2O
Acta Cryst. (2007). C63, o21±o25

organic compounds
Re®nement
(Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); soft-
ware used to prepare material for publication: SHELXL97 and
PRPKAPPA (Ferguson, 1999).
Re®nement on F2
R[F2 > 2ꢅ(F2)] = 0.040
wR(F2) = 0.121
S = 1.10
2551 re¯ections
w = 1/[ꢅ2(F2o) + (0.0673P)2
+ 0.2827P]
where P = (F2o + 2Fc2)/3
(Á/ꢅ)max < 0.001
3
X-ray data were collected at the EPSRC National Crystal-
lography Service, University of Southampton, England. The
authors thank the staff for all their help and advice. MN and
Ê
Áꢇmax = 0.32 e A
3
Ê
0.28 e A
155 parameters
H-atom parameters constrained
Áꢇmin
=
Â
Â
JC thank the Consejerõa de Innovacion, Ciencia y Empresa
Table 3
Hydrogen-bond geometry (A, ) for (III).
Â
Â
(Junta de Andalucõa, Spain) and the Universidad de Jaen
for ®nancial support. JP thanks COLCIENCIAS and
UNIVALLE (Universidad del Valle, Columbia) for ®nancial
support that has also supported a short stay at Instituto de
Quõmica Organica de Sõntesis, Universidad Nacional de
Rosario. EGM thanks CONICET and Universidad Nacional
de Rosario for ®nancial support.
ꢀ
Ê
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
O12ÐH12Á Á ÁO1
0.95
0.90
0.90
0.91
0.91
1.66
1.90
2.06
2.31
2.01
2.6005 (13)
2.8002 (16)
2.9556 (15)
3.1446 (17)
2.9020 (15)
172
176
180
152
168
O1ÐH1AÁ Á ÁN42i
O1ÐH1BÁ Á ÁN45ii
N45ÐH45AÁ Á ÁN42iii
N45ÐH45BÁ Á ÁO11iv
Â
Â
Â
Symmetry codes: (i) x; y ‡ 1; z ‡ 1; (ii) x ‡ 1; y ‡ 1; z ‡ 1; (iii) x ‡ 12, y ‡ 21,
1
2
z ‡ 12; (iv) x ‡ 21; y ‡ 32; z
.
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: GG3055). Services for accessing these data are
described at the back of the journal.
For compounds (II) and (III), the space groups P21/c and P21/n,
respectively, were uniquely assigned from the systematic absences.
Crystals of compound (I) are triclinic; space group P1 was selected
and con®rmed by the structure analysis. All H atoms were located in
difference maps and then treated as riding atoms. H atoms bonded to
C atoms were assigned standard CÐH distances [0.95 (aromatic),
References
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Ê
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Ê
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Ê
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È
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È
ꢁ
Acta Cryst. (2007). C63, o21±o25
Portilla et al.
C13H15N3O2, C15H19N3O2 and C11H11N3O2ÁH2O o25