5-[N-(1H-benzotriazol-1-ylmethyl)-amino]-3-tert-butyl-1-phenylpyrazole: Sheets built from N-H...N, C-H...N and C-H...π(pyrazole) interactions

Article abstract of DOI:10.1107/S0108270102006881

In the title compound, C₂₀H₂₂N₆, the molecules are linked into a chain of rings by N-H...N [H...N 2.16 A, N...N 2.950 (3) A and N-H...N 149°] and C-H...N [H...N 2.55 A, C...N 3.481 (3) A and C-H...N 165°] hydrogen bonds, and these chains are linked into sheets by means of C-H...π(pyrazole) interactions.

Full text of DOI:10.1107/S0108270102006881

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
atom N4 at (x, y, z) acts as hydrogen-bond donor to triazole
N3 at (2 x, 12 + y, 12 z), while N4 at (2 x, 21 + y, 12 z),
in turn, acts as donor to N3 at (x, 1 + y, z), so producing a
C(6) chain generated by the 21 screw axis along (1, y, 14). This is
ISSN 0108-2701
5-[N-(1H-Benzotriazol-1-ylmethyl)-
amino]-3-tert-butyl-1-phenylpyrazole:
sheets built from NÐHÁ Á ÁN,
CÐHÁ Á ÁN and CÐHÁ Á Áp(pyrazole)
interactions
Christopher Glidewell,a* John N. Low,b Justo Cobo,c
c
c
d
Â
Manuel Nogueras, Adolfo Sanchez, Emerson Rengifo
and Rodrigo Aboniad
aSchool of Chemistry, University of St Andrews, St Andrews, Fife KY16 9ST,
Scotland, bDepartment of Chemistry, University of Aberdeen, Meston Walk, Old
c
Â
Â
Â
Aberdeen AB24 3UE, Scotland, Departamento de Quõmica Inorganica y Organica,
d
Â
Â
Â
Universidad de Jaen, 23071 Jaen, Spain, and Grupo de Investigacion de
Â
Â
Compuestos Heterocõclicos, Departamento de Quõmica, Universidad del Valle,
AA25360 Cali, Colombia
Correspondence e-mail: cg@st-andrews.ac.uk
augmented by a fairly weak CÐHÁ Á ÁN hydrogen bond; C3 at
(x, y, z) acts as donor to triazole N2 at (2 x, 12 + y, 21 z),
producing a C(5) chain generated by the same screw axis as
before, so that the resulting chain of rings running parallel to
the [010] direction (Fig. 2) has the descriptor C(5)C(6)[R22(9)]
(Bernstein et al., 1995). Two chains of this type run through
each unit cell, in the domains 0.06 < z < 0.44 and 0.56 < z <
0.94, and within each domain, adjacent chains are linked into a
(001) sheet by CÐHÁ Á Áꢀ(pyrazole) interactions. Atom C19 in
the molecule at (x, y, z), which lies in the hydrogen-bonded
chain along (1,y,14), forms a short CÐHÁ Á Áꢀ contact (Table 2)
with the centroid, Cg2, of the pyrazole ring of the molecule at
(1 x, 12 + y, 12 z), which itself lies in the hydrogen-bonded
Received 12 April 2002
Accepted 17 April 2002
Online 11 May 2002
In the title compound, C20H22N6, the molecules are linked into
Ê
a chain of rings by NÐHÁ Á ÁN [HÁ Á ÁN 2.16 A, NÁ Á ÁN
ꢀ
Ê
2.950 (3) A and NÐHÁ Á ÁN 149 ] and CÐHÁ Á ÁN [HÁ Á ÁN
ꢀ
Ê
Ê
2.55 A, CÁ Á ÁN 3.481 (3) A and CÐHÁ Á ÁN 165 ] hydrogen
bonds, and these chains are linked into sheets by means of
CÐHÁ Á Áꢀ(pyrazole) interactions.
Comment
The title compound, (I) (Fig. 1), was prepared as a precursor
for the synthesis of new hydrogenated pyrazolo±pyridines
using the benzotriazole methodology (Katritzky et al., 1995,
1998; Abonia et al., 2001).
The CÐC bond distances (Table 1) in the fused arene ring
show some evidence for bond ®xation, with bonds C3ÐC4 and
C5ÐC6 being shorter than the neighbouring bonds; likewise,
the N2ÐN3 bond is markedly shorter than both N1ÐN2 and
N5ÐN6. The pattern of CÐN distances is of interest; the C7Ð
N1 and C7ÐN4 distances, which involve planar three-
connected N and four-connected C atoms, are signi®cantly
different; likewise, the C1ÐN3 and C9ÐN6 distances, which
involve two-connected N and planar three-connected C atoms,
differ signi®cantly, consistent with the occurrence of single and
double bonds, respectively. On the other hand, the three
distances C2ÐN1, C8ÐN4 and C8ÐN5, which involve two
planar three-connected atoms, span only a small range.
The supramolecular structure of (I) is determined by a
combination of NÐHÁ Á ÁN and CÐHÁ Á ÁN hydrogen bonds
and CÐHÁ Á Áꢀ(pyrazole) interactions (Table 2). The amino
Figure 1
The molecule of (I), showing the atom-labelling scheme. Displacement
ellipsoids are drawn at the 30% probability level.
o314 # 2002 International Union of Crystallography
DOI: 10.1107/S0108270102006881
Acta Cryst. (2002). C58, o314±o317

organic compounds
Figure 4
Stereoview of part of the crystal structure of (II), showing the formation
of a molecular ladder built from NÐHÁ Á ÁN and NÐHÁ Á Áꢀ(triazole)
interactions.
code: (i) x, y, 1 + z], forming C(8) chains by translation.
However, re-examination of the structure of (II) in the light of
the above analysis for (I), shows that there is also a short NÐ
HÁ Á Áꢀ(triazole) interaction, involving the N51ÐH52 bond,
which does not participate in conventional hydrogen bonding,
Figure 2
Part of the crystal structure of (I), showing the formation of a chain of
rings along [010]. Atoms marked with an asterisk (*) or hash (#) are at the
x, 12 + y,
1
2
1
2
symmetry positions (2 x, 12 + y,
respectively.
z) and (2
z),
ii
Ê
and the centroid (Cg2) of the triazole ring; H52Á Á ÁCg2 2.72 A,
N51Á Á ÁCg2ii 3.477 (2) A and N51ÐH52Á Á ÁCg2ii 146ꢀ
Ê
chain along (12,y,14) (Fig. 3). Propagation of this interaction thus
links all of the [010] chains in a given domain of z into a single
sheet. Two sheets run through each unit cell, but there are no
direction-speci®c interactions between adjacent sheets.
The structure of the isomeric compound (II) (see Scheme
above) has recently been reported in space group P21/c (Low
et al., 2002). The supramolecular structure was described in
terms of a single hydrogen bond, N51ÐH51Á Á ÁN43i [symmetry
[symmetry code: (ii) x, 12 y, 21 + z]. This interaction produces
a zigzag chain parallel to [001], generated by the c-glide plane
at y = 14. The combination of NÐHÁ Á ÁN and NÐHÁ Á Áꢀ
interactions thus generates a double chain, or molecular
ladder (Fig. 4).
Since CÐHÁ Á Áꢀ interactions most frequently involve
benzenoid rings as acceptors (Desiraju & Steiner, 1999;
Suezawa et al., 2001), with rather few examples involving
Figure 3
Part of the crystal structure of (I), showing the linking of the [010] chains
by CÐHÁ Á Áꢀ(pyrazole) interactions. Atoms marked with an asterisk (*)
Figure 5
Part of the crystal structure of (IV), showing the formation of a CÐ
HÁ Á Áꢀ(pyrazole) chain consisting of type 1 molecules only.
1
2
or hash (#) are at the symmetry positions (1 x, 12 + y,
(1 x, 12 + y, 12 z), respectively.
z) and
ꢁ
Acta Cryst. (2002). C58, o314±o317
Christopher Glidewell et al. C20H22N6 o315

organic compounds
Crystal data
heterocycles, we have brie¯y investigated the occurrence of
CÐHÁ Á Áꢀ(pyrazole) interactions by examining the structures
of pyrazoles in the Cambridge Structural Database (CSD;
Allen & Kennard, 1993) containing the fragment (III), namely
a pyrazole ring carrying the same substituent atoms as found
in (I). Nine examples were retrieved; the structures of three of
these contained only CÐHÁ Á Áꢀ(arene) interactions, those of
®ve others contained no CÐHÁ Á Áꢀ interactions at all, but the
structure of the ninth [CSD refcode TIXPEV, (IV); Ramm et
al., 1996], which crystallizes in space group P21/a with Z0 = 2,
displays quite short CÐHÁ Á Áꢀ(pyrazole) interactions, such
that the two independent molecules each form simple chains.
For the type 1 molecules, the chain is generated by the a-glide
C20H22N6
Mr = 346.44
Orthorhombic, P212121
Ê
a = 7.2380 (5) A
Ê
b = 11.9743 (9) A
c = 21.2062 (16) A
Ê
V = 1837.9 (2) A
Z = 4
Dx = 1.252 Mg m
Mo Kꢁ radiation
Cell parameters from 2418
re¯ections
ꢂ = 1.9±27.4ꢀ
ꢃ = 0.08 mm
T = 120 (2) K
1
Ê
3
Plate, colourless
0.30 Â 0.20 Â 0.07 mm
3
Data collection
Bruker SMART1000 CCD
diffractometer
' and ! scans
Absorption correction: multi-scan
(SADABS; Bruker, 1997)
Tmin = 0.979, Tmax = 0.995
12 704 measured re¯ections
2418 independent re¯ections
2200 re¯ections with I > 2ꢄ(I)
Rint = 0.030
ꢂmax = 27.4ꢀ
h = 7 ! 9
k = 15 ! 15
iii
iii
1
Ê
Ê
plane at y = 4 [HÁ Á ÁCg1 2.84 A, CÁ Á ÁCg1 3.645 (2) A and
l = 27 ! 27
CÐHÁ Á ÁCg1iii 127ꢀ; symmetry code: (iii) 12 + x,
y, z]
(Fig. 5), while for the type 2 molecules, the chain is generated
1
2
Intensity decay: negligible
by the a-glide plane at y = [HÁ Á ÁCg2iv 2.69 A, CÁ Á ÁCg2
iv
1
Ê
Re®nement
4
iv
ꢀ
1
Ê
Re®nement on F2
R[F2 > 2ꢄ(F2)] = 0.044
wR(F2) = 0.108
w = 1/[ꢄ2(Fo2) + (0.0692P)2
+ 0.2514P]
3.537(2) A and CÐHÁ Á ÁCg2 145 ; symmetry code: (iv) 2 + x,
where P = (Fo2 + 2Fc2)/3
(Á/ꢄ)max < 0.001
S = 1.07
2418 re¯ections
238 parameters
H-atom parameters constrained
3
Ê
Áꢅmax = 0.32 e A
3
Ê
0.25 e A
Áꢅmin
=
Table 1
Selected interatomic distances (A).
Ê
C1ÐC2
C2ÐC3
C3ÐC4
C4ÐC5
C5ÐC6
C6ÐC1
C1ÐN3
C2ÐN1
N1ÐN2
1.397 (3)
1.408 (3)
1.371 (3)
1.415 (4)
1.373 (4)
1.397 (3)
1.376 (3)
1.361 (3)
1.361 (2)
N2ÐN3
N1ÐC7
C7ÐN4
N4ÐC8
C8ÐN5
N5ÐN6
N6ÐC9
C9ÐC10
C10ÐC8
1.305 (3)
1.468 (3)
1.422 (3)
1.372 (3)
1.359 (3)
1.383 (2)
1.327 (3)
1.412 (3)
1.388 (3)
Table 2
Hydrogen-bonding geometry (A, ).
ꢀ
Ê
Cg2 is the centroid of the N5/N6/C8±C10 pyrazole ring.
Figure 6
Part of the crystal structure of (IV), showing the formation of a CÐ
HÁ Á Áꢀ(pyrazole) chain consisting of type 2 molecules only.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
N4ÐH4AÁ Á ÁN3i
C19ÐH19Á Á ÁCg2ii
0.88
0.95
0.95
2.16
2.55
2.85
2.950 (3)
3.481 (3)
3.779 (3)
149
165
167
C3ÐH3Á Á ÁN2i
1
2
y, z] (Fig. 6), where Cg1 and Cg2 represent the ring
centroids of the pyrazole rings in the molecules of types 1 and
2, respectively.
1
2
1
2
1 1
Symmetry codes: (i) 2 x; y
;
z; (ii) 1 x; y
;
2 2
z.
Experimental
Compound (I) crystallized in the orthorhombic system; space
group P212121 was assigned uniquely from the systematic absences. H
atoms were treated as riding, with CÐH distances in the range 0.95±
A solution of 5-amino-3-tert-butyl-1-phenylpyrazole (Grandberg et
al., 1961; Abonia et al., 2002) (1.00 g, 4.65 mmol) and 1-hydroxy-
methylbenzotriazole (Burckhalter et al., 1952) (0.70 g, 4.69 mmol) in
ethanol (5 ml) was heated under re¯ux for 3 min. After cooling, the
precipitate which formed was ®ltered off and washed with ethanol,
giving (I) as a white solid (84% yield; m.p. 453 K; analysis, found:
C 69.3, H 6.4, N 24.2%; C20H22N6 requires: C 69.3, H 6.4, N 24.3%).
Crystals suitable for single-crystal X-ray diffraction were grown from
a solution in ethanol.
Ê
Ê
0.99 A and an NÐH distance of 0.88 A. The Friedel equivalent
re¯ections were merged prior to the ®nal re®nements, as the absolute
structure could not be assigned.
Data collection: SMART (Bruker, 1997); cell re®nement: SMART;
data reduction: SHELXTL (Bruker, 1997); program(s) used to solve
structure: SHELXS97 (Sheldrick, 1997); program(s) used to re®ne
structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
ꢁ
o316 Christopher Glidewell et al.
C20H22N6
Acta Cryst. (2002). C58, o314±o317

organic compounds
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem.
Int. Ed. Engl. 34, 1555±1573.
Bruker (1997). SADABS, SMART and SHELXTL. Bruker AXS Inc.,
Madison, Wisconsin, USA.
PLATON (Spek, 2002); software used to prepare material for
publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).
X-ray data were collected at the EPSRC X-ray Crystal-
lographic Service, University of Southampton, England. 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.
Burckhalter, J. H., Stephens, V. C. & Hall, L. A. (1952). J. Am. Chem. Soc. 74,
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Desiraju, G. R. & Steiner, T. (1999). The Weak Hydrogen Bond, pp. 122±193.
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Supplementary data for this paper are available from the IUCr electronic
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Â
Low, J. N., Cobo, J., Nogueras, M., Sanchez, A., Rengifo, E. & Abonia, R.
(2002). Acta Cryst. E58, o53±o54.
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ꢁ
Acta Cryst. (2002). C58, o314±o317
Christopher Glidewell et al. C20H22N6 o317