2′-(4-Chlorophenyl)-2,3,4,5,6,7-hexahydro-4′, 7′-methano-spiro-[9H-fluorene9,3′-1H-indazole]-1′- carbonitrile and methyl 4′-chloro-2′-(4-chlorophenyl)-1′- cyanospiro-[9H-fluorene-9,3′-pyrazolidine]-4′-carboxylate

Article abstract of DOI:10.1107/S0108270107053619

The title compounds, C27H22ClN3, (IV), and C24H17Cl2N3O2, (V), were synthesized as part of our ongoing studies on (2+3)-cyclo-addition reactions. Compound (V) crystallizes with two mol-ecules in the asymmetric unit. The pyrazolidine ring of compound (IV) adopts a twisted conformation, while in compound (V) it adopts a twisted and an envolope conformation in the two molecules. There are short inter-molecular contacts, which can be recognized as unconventional hydrogen bonds, in both structures. International Union of Crystallography 2007.

Full text of DOI:10.1107/S0108270107053619

organic compounds
Acta Crystallographica Section C
Crystal Structure
Communications
cyanoazomethine imine, (III), reacts smoothly with norbor-
nene and methyl ꢀ-chloroacrylate to afford the expected
(2+3)-cycloadducts (IV) and (V), respectively, in high yields.
The streochemical structures of the isolated products were
initially established by Huisgen and co-workers on the basis of
the spectroscopic data (Huisgen et al., 1977; Huisgen & Eckell,
1977b). The (2+3)-cycloaddition with norbornene was
reported to give the exo-oriented cycloadduct (Huisgen &
Eckell, 1977a). In the case of the product obtained from
methyl ꢀ-chloroacrylate, the reaction was reported to lead
mainly to the sterically more crowded regioisomer (V); the
minor product corresponding to the structure (VI) was found
in the mother liquor after separation of (V) (Huisgen &
Eckell, 1977b). The goal of the present work was to resyn-
thesize pyrazolidines (IV) and (V), and to con®rm their
structures and the predicted substitution pattern in the pyra-
zolidine ring by X-ray diffraction analysis. Other features
related to the intermolecular interactions were also of interest.
ISSN 0108-2701
20-(4-Chlorophenyl)-2,3,4,5,6,7-
hexahydro-40,70-methanospiro[9H-
fluorene-9,30-1H-indazole]-10-carbo-
nitrile and methyl 40-chloro-20-(4-
chlorophenyl)-10-cyanospiro[9H-
fluorene-9,30-pyrazolidine]-40-
carboxylate
.
Elzbieta Bilewicz,a* Magdalena Maøecka,a Søawomir J.
a
Âb
Grabowski and Grzegorz Mloston
a
Â
Â
Department of Crystallography and Crystal Chemistry, University of èodz, Pomorska
149/153, PL-90236 èodz, Poland, and bDepartment of Organic and Applied
Â
Â
Â
Â
Â
Â
Chemistry, University of èodz, Narutowicza 68, PL-90136 èodz, Poland
Correspondence e-mail: ebilewicz@uni.lodz.pl
Received 6 September 2007
Accepted 26 October 2007
Online 24 November 2007
The title compounds, C27H22ClN3, (IV), and C24H17Cl2N3O2,
(V), were synthesized as part of our ongoing studies on (2+3)-
cycloaddition reactions. Compound (V) crystallizes with two
molecules in the asymmetric unit. The pyrazolidine ring of
compound (IV) adopts a twisted conformation, while in
compound (V) it adopts a twisted and an envolope
conformation in the two molecules. There are short inter-
molecular contacts, which can be recognized as unconven-
tional hydrogen bonds, in both structures.
Comment
Azomethine imines, (I), belong to the class of well known and
widely applied 1,3-dipoles (Grashey, 1984). They undergo
(2+3)-cycloadditions with both electron-rich and electron-
de®cient ethylene derivatives to yield the corresponding 1,2-
pyrazolidine derivatives of type (II). N-Cyano-substituted
pyrazolidines are of interest because of their expected bio-
logical activity; for example, some of them were tested as
cathepsin K inhibitors for the treatment of osteoporosis
(Deaton et al., 2005). The mechanism of the (2+3)-cyclo-
addition in the case of azomethine imines is believed to follow
the concerted pathway that results in stereospeci®c formation
of the ®nal cycloadducts (Huisgen & Eckell, 1977a). For the
purposes of organic synthesis, an especially attractive group of
1,3-dipoles is formed by relatively stable and reactive
azomethine imines of type (III) prepared from 4-chloro-
phenyldiazocyanide and diaryl derivatives of diazomethane,
described for the ®rst time by Huisgen et al. (1977). The yellow
crystalline C-(2,20-biphenylylene)-Nꢀ-(4-chlorophenyl)-Nꢁ-
Compound (IV) (Fig. 1) crystallizes with one molecule and
compound (V) (Fig. 2) with two independent molecules in the
asymmetric unit [(V-A) and (V-B)]. The weighted r.m.s. ®t of
Ê
the non-H atoms from the two molecules of (V) is 2.88 A
(Mackay, 1984). The largest deviation from perfect overlap is
observed for the ¯uorene group. The molecules of both
compounds contain the pyrazolidine ring as a relevant frag-
Acta Cryst. (2007). C63, o739±o742
DOI: 10.1107/S0108270107053619
# 2007 International Union of Crystallography o739

organic compounds
ment of the structure. The substituents at atoms C3, N1 and
N2 in both compounds are identical, as they originate from the
same 1,3-dipole, (IIIa). In the molecule of (IV), the norbor-
nane ring is fused with the heterocyclic ring, and in the case of
(V), the Cl atom and ester group are bonded to atom C4. Thus,
the regiochemical structure attributed to (V) by Huisgen &
Eckell (1977a) was correct. Moreover, the structure of (IV)
shows that the pyrazolidine ring is exo-oriented with respect to
the norbornane skeleton. It is worth mentioning that an
analogous orientation was proposed for (2+3)-cycloadducts
obtained from norbornene and other 1,3-dipoles, for example,
diphenylnitrilimine, benzonitrile N-oxide (Huisgen et al.,
1967) and methyl diazoacetate (Gorpinchenko et al., 2006).
The sums of the bond angles around atom N1 [atom N101 in
(V-B)] are 343 (1), 336 (1) and 336 (1)ꢀ for (IV), (V-A) and
(V-B), respectively, while the corresponding angle sums
around atom N2 [atom N102 in (V-B)] are 324 (1), 342 (1) and
343 (1)ꢀ, respectively. These values indicate signi®cant pyra-
midalization at these N atoms. A similar pyramidalization
about the cyano N atom is found in other heterocyclic
compounds containing the ±NÐC N group (Bird et al.,
1995). In contrast, the amine N atom of the parent cyanamide,
CH2N2, has a geometry that is somewhat ¯atter; the sums of
the bond angles were found to be 356 (2)ꢀ in a low-tempera-
ture X-ray study (Denner et al., 1988), and 349.3 (7) and
349.6 (7)ꢀ in a study based on neutron data and an X-ray
multipole re®nement, respectively, for a host±guest complex
of cyanamide in 18-crown-6 (Koritsanszky et al., 1991).
The pyrazolidine ring in each compound is nonplanar, as
the three C atoms and two N atoms are sp3-hybridized. In
(IV), this ring adopts a twisted conformation, with the pseudo-
twofold axis passing through the mid-point of the N2ÐC3
bond and atom C5. For (IV), the puckering parameters
(Cremer & Pople, 1975) for the atom sequence N1ÐN2Ð
ꢀ
Ê
C3ÐC4ÐC5 are q2 = 0.385 (1) A and '2 = 229.8 (2) [asym-
metry parameter (Nardelli, 1983) Á2 = 0.019 (1)]. The
substituents at atoms N1 and N2 occupy equatorial positions,
while atoms C41 and C44 are in axial positions with respect to
the pyrazolidine ring. The pyrazolidine ring of (V) adopts an
envelope conformation in molecule A, with a pseudo-mirror
passing through atom C4 and the mid-point of the N1ÐN2
bond. In molecule B, the ring has a twisted conformation, with
Figure 1
The molecular structure of (IV), showing the atomic numbering scheme
and 40% probability displacement ellipsoids. H atoms have been omitted
for clarity.
Figure 2
The molecular structures of the two symmetry-independent molecules of (V), showing the atomic numbering schemes and 40% probability displacement
ellipsoids. The CÐHÁ Á ÁN interaction forming dimers between molecules A and B is shown as a dashed line. The other H atoms have been omitted for
clarity.
ꢁ
o740 Bilewicz et al. C27H22ClN3 and C24H17Cl2N3O2
Acta Cryst. (2007). C63, o739±o742

organic compounds
the pseudo-twofold axis passing through the mid-point of the
C104ÐC105 bond and atom N102. For (V-A), the puckering
parameters for the atom sequence N1ÐN2ÐC3ÐC4ÐC5 are
(Fig. 3). This generates a graph-set motif of C(9) (Etter et al.,
1990). In contrast, molecules A and B in (V) are linked into
ꢀ
Ê
q2 = 0.400 (2) A and '2 = 295.1 (3) [asymmetry parameter
Ás = 0.041 (1)], while for (V-B) the puckering parameters for
the atom sequence N101ÐN102ÐC103ÐC104ÐC105 are q2 =
ꢀ
Ê
0.389 (2) A and '2 = 128.4 (3) [Á2 = 0.013 (1)]. The different
puckering of the pyrazolidine rings of molecules A and B
causes differences in the orientations of the substituents. The
cyano group at atom N1 is nearly axial and perfectly axial at
atom N101. In both molecules of compound (V), the chloro-
phenyl substituent at atom N2 (N102) occupies a nearly
equatorial position, while the Cl and ester substituents at atom
C4 (C104) occupy axial and equatorial positions, respectively.
The bonds distances and angles in all three molecules are
mostly in good agreement with expected values (Allen et al.,
1987). However, the NÐN bond distances are longer than
dimers by a weak C5ÐH5BÁ Á ÁN107 interaction; atom N7 does
not act as an acceptor in any interaction. In addition, some
weak nonclassical intermolecular CÐHÁ Á ÁO, CÐHÁ Á ÁCl and
CÐHÁ Á Áꢂ interactions are observed. For (IV), a CÐHÁ Á Áꢂ
interaction (see Table 1, where Cg1 is the centroid of the C8±
C13 ring of the ¯uorene group) involves pairs of molecules
related by a centre of inversion. For (V) (see Table 2, where
Cg2 is the centroid of the C121±C126 ring of molecule B), all
interactions emanate from H atoms solely in molecule A and
the acceptor atoms are in one adjacent molecule A and three
different B molecules.
Ê
expected. The long N1ÐN2 bond of 1.4785 (15) A in (IV) and
Ê
1.458 (3) and 1.445 (3) A in (V-A) and (V-B), respectively,
may be caused by the in¯uence of the cyano and chlorophenyl
substituents on the pyrazolidine ring. Moreover, a search of
the Cambridge Structural Database (Version 5.28 of
November 2006; Allen, 2002) for structures containing the
pyrazolidine fragment (see scheme below), revealed a range of
Experimental
Compound (III) was prepared following a literature protocol
(Huisgen et al., 1977); compounds (IV) and (V) were synthesized
from (III) and commercial norbornene or methyl ꢀ-chloroarylate,
according to the procedures reported by Huisgen & Eckell (1977a)
and Huisgen & Eckell (1977b), respectively. Crystals suitable for
X-ray measurement were obtained by slow evaporation from a
dichloromethane/methanol (1:3) mixture. The melting points are 458±
459 K for (IV) and 454±455 K for (V) [the previously reported
melting points were 461±462 K for (IV) (Huisgen & Eckell, 1977a)
and 456±457 K for (V) (Huisgen & Eckell, 1977b)].
Ê
NÐN bond lengths from 1.387 to 1.514 A for 42 structures.
The search was limited to ordered structures, without errors,
with R less than 0.05 and an average bond length s.u. smaller
Ê
than 0.005 A.
In (IV), atom N7i [symmetry code: (i) x 1, y, z] is involved
in an unconventional C17ÐH17Á Á ÁN7i hydrogen bond, which
links the molecules into chains along the [100] direction
Compound (IV)
Crystal data
3
Ê
C27H22ClN3
Mr = 423.93
V = 2116.5 (3) A
Z = 4
Monoclinic, P21=n
Mo Kꢀ radiation
ꢃ = 0.20 mm
T = 173 (2) K
0.35 Â 0.15 Â 0.10 mm
1
Ê
a = 9.0914 (9) A
Ê
b = 12.6225 (9) A
Ê
c = 18.5025 (17) A
ꢁ = 94.576 (8)ꢀ
Data collection
Stoe IPDSII image-plate
diffractometer
17870 measured re¯ections
5071 independent re¯ections
3437 re¯ections with I > 2ꢄ(I)
Rint = 0.046
Re®nement
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.081
S = 0.85
280 parameters
H-atom parameters constrained
3
Ê
Áꢅmax = 0.24 e A
3
Ê
0.30 e A
5071 re¯ections
Áꢅmin
=
Table 1
Short-contact geometry (A, ) for (IV).
ꢀ
Ê
Cg1 is the centroid of the C8±C13 ring.
DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C17ÐH17Á Á ÁN7i
0.93
0.97
2.65
2.74
3.418 (1)
3.484 (2)
141
134
Figure 3
C42ÐH42BÁ Á ÁCg1ii
Part of the crystal structure of (IV), showing the CÐHÁ Á ÁN interaction
forming chains along the a axis. The symmetry code is given in Table 1.
Symmetry codes: (i) x 1; y; z; (ii) x ‡ 2; y ‡ 1; z ‡ 1.
ꢁ
Acta Cryst. (2007). C63, o739±o742
Bilewicz et al. C27H22ClN3 and C24H17Cl2N3O2 o741

organic compounds
Compound (V)
re®ne structure: SHELXL97 (Sheldrick, 1997); molecular graphics:
PLATON (Spek, 2003); software used to prepare material for
publication: SHELXL97 and WinGX (Farrugia, 1999).
Crystal data
3
Ê
C24H17Cl2N3O2
Mr = 450.31
V = 4142.6 (3) A
Z = 8
The authors are grateful to Professor Werner Massa and the
staff of the X-ray laboratory at the University of Marburg,
Germany, where the data were collected, for skilful experi-
mental assistance. This work was ®nancially supported by the
Monoclinic, P21=c
Mo Kꢀ radiation
ꢃ = 0.34 mm
T = 120 (2) K
0.37 Â 0.37 Â 0.08 mm
1
Ê
a = 11.1818 (5) A
Ê
b = 13.2534 (4) A
Ê
c = 28.1265 (11) A
ꢁ = 96.363 (3)ꢀ
 Â
University of èodz [grant Nos. 505/706, 2007 and 505/712 (to
GM)].
Data collection
Stoe IPDSII image-plate
diffractometer
23396 measured re¯ections
7295 independent re¯ections
4866 re¯ections with I > 2ꢄ(I)
Rint = 0.045
Supplementary data for this paper are available from the IUCr electronic
archives (Reference: LN3061). Services for accessing these data are
described at the back of the journal.
Re®nement
R[F2 > 2ꢄ(F2)] = 0.036
wR(F2) = 0.079
S = 1.02
559 parameters
H-atom parameters constrained
3
Ê
Áꢅmax = 0.84 e A
3
References
Ê
0.41 e A
7295 re¯ections
Áꢅmin
=
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13161±13166.
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Hydrogen-bond geometry (A, ) for (V).
ꢀ
Ê
Cg2 is the centroid of the C121±C126 ring.
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DÐHÁ Á ÁA
DÐH
HÁ Á ÁA
DÁ Á ÁA
DÐHÁ Á ÁA
C5ÐH5BÁ Á ÁN107
C23ÐH23Á Á ÁO142i
C25ÐH25Á Á ÁCg2ii
C44ÐH44AÁ Á ÁCl1iii
0.99
0.95
0.95
0.98
2.51
2.57
2.50
2.77
3.459 (3)
3.502 (3)
3.400 (2)
3.425 (3)
160
166
158
125
Symmetry codes: (i) x ‡ 1; y ‡ 1; z; (ii) x; y ‡ 1; z; (iii) x; y ‡ 12; z ‡ 21.
All H atoms were positioned geometrically and re®ned using a
riding model. In (IV), Uiso(H) values were constrained to 1.2Ueq(C),
Ê
with CÐH distances of 0.98, 0.97 and 0.93 A for methine, methylene
È
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(1967). Chem. Ber. 100, 1580±1588.
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M. & Patz, M. (1991). J. Am. Chem. Soc. 113, 8388±8398.
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and aromatic groups, respectively. In (V), for methyl H atoms,
Uiso(H) values were constrained to 1.5Ueq(C), with CÐH distances of
Ê
Ê
0.98 A; the CÐH distances are 0.95 and 0.99 A for the aromatic and
methylene groups, respectively, with Uiso(H) values constrained to
1.2Ueq(C).
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È
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ꢁ
o742 Bilewicz et al. C27H22ClN3 and C24H17Cl2N3O2
Acta Cryst. (2007). C63, o739±o742