Nonclassical Pschorr and Sandmeyer reactions in pyrazole series

Article abstract of DOI:10.1002/hlca.200590161

The diazonium salt derived from 4-amino-N,1,3-trimethyl-N-(3-methyl-1- phenyl-1H-pyrazol-5-yl)-1H-pyrazole-5-carboxamide (14) was reacted with a mixture of CuSO₄ and NaCl, with ascorbic acid as an initiator to afford the planar derivative 4,6-dihydro-1,4,6,8-tetramethyl-3- phenyldipyrazolo[3,4-b:4′,3′-d]pyridin-5(3H)-one (16) and its unexpected isomer 4,6-dihydro-3,4,6,8-tetramethyl-1-phenyldipyrazolo[4,3-b: 4′,3′-d]pyridin-5(1H)-one (17), as well as the epimers (3S,4S)- (or (3S,4R)-) and (3S,4S)- (or (3S,4S)-) 4-chloro-2,4-dihydro-1′,3′,5, 5′-tetramethyl-2-phenylspiro[pyrazole-3,4′(1′H)-pyrrolo[3,4-c] pyrazol]-6′(5′H)-one (18a and b, respectively). Epimers 18a and b were converted under basic conditions to 4′-chloro-N,1,3,3′- tetramethyl-1′-phenyl-[4,5′-bi-1H-pyrazole]-5-carboxamide (19). The structures of isomers 16 and 17 determined by single-crystal X-ray analysis are also reported. Linear dichroism (LD) measurements for the above isomers suggest that 17 intercalates into DNA, and 17 exhibited antiproliferation activity against human NCI-H460 pulmonary carcinoma cells.

Full text of DOI:10.1002/hlca.200590161

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Helvetica Chimica Acta Vol. 88 (2005)
Nonclassical Pschorr and Sandmeyer Reactions in Pyrazole Series
by Benedetta Maggioa), Giuseppe Daidone*a), Demetrio Raffaa), Salvatore Plesciaa), Gabriella Bombierib),
and Fiorella Meneghettib)
a
¡
) Dipartimento di Chimica e Tecnologie Farmaceutiche, Universita di Palermo, Via Archirafi 32, I-90123
Palermo (phone: ‡ 390916236116; fax: ‡ 390916236119; e-mail: gdaidone@unipa.it)
b
¡
) Istituto di Chimica farmaceutica e tossicologica, Universita di Milano, Viale Abruzzi 42, I-29131 Milano
The diazonium salt derived from 4-amino-N,1,3-trimethyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-1H-
pyrazole-5-carboxamide (14) was reacted with a mixture ofCuSO 4 and NaCl, with ascorbic acid as an initiator to
afford the planar derivative 4,6-dihydro-1,4,6,8-tetramethyl-3-phenyldipyrazolo[3,4-b:4',3'-d]pyridin-5(3H)-
one (16) and its unexpected isomer 4,6-dihydro-3,4,6,8-tetramethyl-1-phenyldipyrazolo[4,3-b:4',3'-d]pyridin-
5(1H)-one (17), as well as the epimers (3S,4S)- (or (3S,4R)-) and (3S,4R)- (or (3S,4S)-) 4-chloro-2,4-dihydro-
1',3',5,5'-tetramethyl-2-phenylspiro[pyrazole-3,4'(1'H)-pyrrolo[3,4-c]pyrazol]-6'(5'H)-one (18a and b, respec-
tively). Epimers 18a and b were converted under basic conditions to 4'-chloro-N,1,3,3'-tetramethyl-1'-phenyl-
[4,5'-bi-1H-pyrazole]-5-carboxamide (19). The structures ofisomers 16 and 17 determined by single-crystal X-
ray analysis are also reported. Linear dichroism (LD) measurements for the above isomers suggest that 17
intercalates into DNA, and 17 exhibited antiproliferation activity against human NCI-H460 pulmonary
carcinoma cells.
Introduction. Previously, we reported the transformation of diazonium salt 2,
derived from 2-amino-N-methyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)benzamide
(1). This reaction was carried out with CuSO4 and NaCl, with ascorbic acid as a
reducing agent (Scheme 1). The diazonium sulfate 2 afforded neither the chloro
derivative 3, the product ofthe classical Sandmeyer reaction, nor the tricyclic derivative
5, the expected product ofthe competitive Pschorr ring closure. Instead, we obtained
epimers 7 and 8, the formation of which can be considered examples of consecutive
nonclassical Pschorr and Sandmeyer reactions [1], presumably via radical intermedi-
ates 4 and 6 (Scheme 1). The isomeric product 9 was formed by treatment of the
mixture ofepimers 7 and 8 with 1m alcoholic KOH, with restoration ofthe aromatic
system ofthe pyrazole nucleus [2].
In continuation ofour research on pyrazole chemistry, we thought it ofinterest to
investigate the above reaction to establish the role ofthe aryl-diazonium moiety in the
reaction pathway. Here, we describe the CuSO4/ascorbic acid-catalyzed decomposition
in the presence ofNaCl ofthe diazonium sulfate 15, which bears a pyrazole-diazonium
moiety in place ofthe benzene-diazonium in 2 (Scheme 2).
Results and Discussion.
Pyrazolecarbonyl chloride 11, obtained in situ, was
reacted with N,3-dimethyl-1-phenyl-1H-pyrazol-5-amine (12) to give nitro derivative
13, which, in turn, was reduced to the corresponding amine 14. The pyrazole-diazonium
salt 15, obtained from 14, was reacted under the same conditions as applied to 2 to
afford the tricyclic isomers 16 and 17 and the chlorinated epimers 18a and b
¹ 2005 Verlag Helvetica Chimica Acta AG, Z¸rich

Helvetica Chimica Acta Vol. 88 (2005)
2273
Scheme 1
a) CuSO4/ascorbic acid/NaCl. b) KOH.
(Scheme 2). The new compounds were characterized by means ofanalytical and
spectral data and, in the case ofisomers 16 and 17, by X-ray analysis.
The 1H-NMR spectra of 16 and 17 showed signals consistent with four Me groups as
shown in the structures. The spectrum ofcompound 16 showed for the Me groups at 3-
positions ofthe two pyrazole nuclei, two closely spaced resonance signals at d 2.59 and
2.62, whereas the corresponding Me groups in isomer 17 produced signals at d 1.47 and
2.69. The high-field signal at d 1.47 is due to the Me group located in the shielding zone
ofthe Ph ring. Further, the pyridinone Me group of 16 but not 17 exhibited carbonyl
diamagnetic anisotropy.
1
The H-NMR spectra ofepimers 18a and b showed signals at d 5.93 and 5.82,
respectively, due to the pyrazoline H-atom, as well as those ofthe four Me groups at d
2.19 3.91 and 2.03 3.86, respectively. The relative configuration of the pyrazoline
C(5)-atom was not determined. A possible mechanism for formation of isomers 16 and
17 and epimers 18a and b is proposed in Scheme 3.
On the basis ofthe experimental results, the radical intermediates 20 and 21
(Scheme 3) are more reactive than the analogous species 4 and 6 (Scheme 1). In fact, in
the intermediate 20, the radical attack at C(4) and C(5) ofthe pyrazole nucleus takes
place to afford the tricyclic system 16 and the radical spiro-species 21, respectively,
whereas the intermediate 4 is transformed to only the spiro-intermediate 6. Species 21

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Helvetica Chimica Acta Vol. 88 (2005)
Scheme 2
Reagents: a) SOCl2 reflux. b) Et3N/CHCl3 reflux. c) Fe/AcOH. d) KNO2/H2SO4. e) CuSO4/ascorbic acid/NaCl.
f) KOH.
produces both epimers 18a and b and rearranges via the N-centered radical 22 to form
17, an isomer of 16, whereas 6 is transformed only to the epimeric couple 7 and 8.
Finally, epimer 18a was reacted with KOH in EtOH solution to give the derivative
19 (Scheme 2). The same result was obtained from reaction of a mixture of 18a and b;
conversion of 18b was confirmed by TLC analysis. The mechanism of the reaction is
probably similar to that proposed for the formation of compound 9 from 8 (Scheme 1)
[2]. This transformation represents a new way to obtain the 5,4'-bipyrazole system.
ORTEP [3] Views ofisomers 16 and 17 are shown in Figs. 1 and 2. The isomers have
in common a tricyclic system with the pyrazolo[3,4-c]pyridin-4-one moieties equally
substituted, but differ in the point of closure of the ring to give the Me- and Ph-
substituted pyrazole. In fact, 17 can be thought ofas being derived from 16 by a 1808
rotation along an ideal axis passing through N(2) and the mid-point ofthe C(8) ÀC(9)
bond, with exchange ofthe relative ring-junction atoms.
The crystal structure of 17 is characterized by the presence ofa molecule ofH O of
2
crystallization, which bridges adjacent molecules via H-bond interactions involving two
N-atoms ofpyrazole at the two terminal parts ofthe tricyclic system with contact
distances N(5) ¥ ¥ ¥ O(H2O) 2.92(1) ä and O(H2O) ¥ ¥ ¥ N(2') 2.94(1) ä (N(5) ¥ ¥ ¥

Helvetica Chimica Acta Vol. 88 (2005)
2275
Scheme 3. Suggested Mechanism for the Transformation of 15
H(111)À(H2O) 1.87 ä, 156(6)8 and (H2O)ÀH(112) ¥ ¥ ¥ N(2') 2.34 ä, 133(8)8; at
1.5 À x, À 1/2 ‡ y, 1.5 À z). The presence ofH O gives rise to infinite chains that
2
develop along the b axis (Fig. 3), while, in 16, which has no crystallized H2O, the
molecules are oriented parallel to the (101) plane, as shown in Fig. 4.
Finally, we thought it ofinterest to verify whether the nearly planar heteroaromatic
isomers 16 and 17 are able to intercalate into DNA. Due to the very low solubility ofthe
compounds, particularly 16, only the somewhat more-soluble 17 could be investigated.
The interaction of 17 with DNA was evaluated by means oflinear dichroism (LD)
experiments according to Vedaldi et al.[4]. The presence ofa small negative band in the
300 350 nm region ofthe LD spectrum ( Fig. 5), corresponding to the maximum
absorption range ofthe compound, was observed, suggesting that the chromophore of
the compound lies parallel to the base pairs ofthe macromolecule, thus indicating
intercalation into the macromolecule. Isomer 17 was also active against proliferation of
human NCI-H460 pulmonary carcinoma cells with a IC50 value of30 mg/ml.
Presumably, the antiproliferation activity is correlated to DNA intercalation.
Conclusions. The radical intermediate 20 derived from diazonium salt 15 exhibits
chemical behavior different from that reported for radical 4 obtained from diazonium

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Helvetica Chimica Acta Vol. 88 (2005)
Fig. 1. ORTEP [3] Drawing of the crystal structure of 16
(ellipsoids at 50% probability; arbitrary numbering)
Fig. 2. ORTEP [3] Drawing of the crystal structure of 17 (ellipsoids at 50% probability, arbitrary numbering)
salt 2. This difference is related to the presence of a dimethyl-substituted pyrazole
radical in 20 in place ofa phenyl radical in 4. The transformation of 20 is based on
intramolecular attack ofthe radical moiety on C(4) and C(5) ofthe phenyl-substituted

Helvetica Chimica Acta Vol. 88 (2005)
2277
Fig. 3. Chain arrangement of the molecules in 17
Fig. 4. Crystal packing of 16
pyrazole ring. To find 17 among the isolated products was quite unexpected, as it forms
as a result ofconsecutive transformations of 20. Isomerization ofepimers 18a and b to
19 under basic conditions represents a new way to obtain the 4,5'-bipyrazole system.
Finally, isomer 17 showed, to some extent, DNA-intercalation, as well as moderate
antiproliferation activity against human NCI-H460 pulmonary carcinoma cells.
Experimental Part
General. M.p.: B¸chi 530 capillary melting-point apparatus; uncorrected. IR Spectra: Perkin-Elmer
Spectrum RXI-FT spectrophotometer; hexachlorobutadiene solns.; n in cmÀ1. 1H-NMR Spectra: Bruker AC-E
250F (250 MHz); in (D6)DMSO; d in ppm rel. to Me4Si as internal standard. MS: Waters AutoSpec-Ultima
orthogonal T.O.F. mass spectrometer; 75 eV; m/z (%). Microanalyses (C, H, N) were performed in the
¡
laboratories ofthe Dipartimento di Scienze Farmaceutiche-Universita di Catania. Compound 17 was dried in a
cell thermostatted at 1508 under vacuum 4 h before analysis.
1,3-Dimethyl-4-nitro-1H-pyrazole-5-carbonyl Chloride (11). 1,3-Dimethyl-4-nitro-1H-pyrazole-5-carboxyl-
ic acid (10; 1.85 g, 10 mmol) [5] was reacted with SOCl2 (12 ml) under reflux for 5 h. The soln. was evaporated
under reduced pressure and the oily residue obtained was dissolved in abs. benzene (20 ml). The soln. was

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Helvetica Chimica Acta Vol. 88 (2005)
Fig. 5. Linear dichroism spectrum of 17 DNA complex (optical path 1 mm)
evaporated under reduced pressure. This last part ofthe procedure was repeated and the oily residue was used in
the next step.
N,1,3-Trimethyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-4-nitro-1H-pyrazole-5-carboxamide (13). A soln.
containing equimolar amounts of 11 and N,3-dimethyl-1-phenyl-1H-pyrazol-5-amine (12; 1.87 g, 10 mmol) [6] in
dry CHCl3 (100 ml) was refluxed for 5 h. After the first hour, Et3N (1.6 ml) was added in four portions (0.8, 0.4,
2 Â 0.2 ml, resp., with intervals of1 h between additions). The soln. was evaporated under reduced pressure, and
the solid residue was washed with H2O (2 Â 100 ml) and crystallized from EtOH to afford 13 (1.06 g, 30%).
1
Crystalline colorless solid. M.p. 136 1378. IR: 1664 (CO). H-NMR: 2.13 (s, Me); 2.78 (s, Me); 3.53 (s, Me);
‡
6.21 (s, HÀC(4) ofpyrazole); 7.16 7.57 ( m, 5 arom. H). MS: 354 (M ). Anal. calc. for C17H18N6O3: C 57.62, H
5.12, N 23.72; found: C 57.47, H 5.19, N 23.59.
4-Amino-N,1,3-trimethyl-N-(3-methyl-1-phenyl-1H-pyrazol-5-yl)-1H-pyrazole-5-carboxamide (14).
A
susp. ofFe filings (8 g) in 5% aq. AcOH (10 ml) was heated at ca. 1008 under stirring on the water bath ofa
rotavapor until H2 evolution ceased. The NO2 derivative 13 (4.6 g, 13 mmol) was added in four portions, with
intervals of20 min between additions. Atfer the last addition, stirring was continued at 100 8 for 1 h, then the
mixture was cooled to r.t. The pH ofthe susp. was adjusted to 7 8 with a sat. soln. ofNaHCO 3. The solid was
separated by filtration, air dried overnight, and then extracted with boiling CHCl3 (3 Â 50 ml). The combined
extracts were evaporated under vacuum, leaving an oily residue that solidified by addition of a small amount of
Et2O to give practically pure 14 (3.12 g, 74%). Crystalline colorless solid. M.p. 122 1248 (Et2O). IR: 3429
3335 (multiple bands), 1634 (CO). 1H-NMR: 1.89 (s, Me); 2.20 (s, Me); 2.85 (s, Me); 3.36 (s, Me); 3.73 (s, NH2
‡
(exchangeable with D2O)); 6.52 (s, HÀC(4) ofpyrazole); 7.13 7.47 ( m, 5 arom. H). MS: 324 (M ). Anal. calc
for C17H20N6O: C 62.95, H 6.21, N 25.91; found: C 62.71, H 6.31, N 25.75.
1,3-Dimethyl-5-{[methyl(3-methyl-1-phenyl-1H-pyrazol-5-yl)amino]carbonyl}-1H-pyrazole-4-diazonium
Sulfate (15). Pulverized 14 (1.49 g, 4.6 mmol) was dissolved in cooled (0 58) 5n H2SO4 (9.2 ml), and 2.5m aq.
NaNO2 (1.92 ml) was added dropwise to the stirred soln. The soln. was stirred for a further 15 min in an ice bath
and then checked for excess HNO2 with KI-starch paper; excess HNO2 was destroyed by addition ofurea.
(3S,4S)- or (3S,4R)-4-Chloro-2,4-dihydro-1',3',5,5'-tetramethyl-2-phenylspiro[3H-pyrazole-3,4'(1'H)-pyr-
rolo[3,4-c]pyrazol]-6'(5'H)-one (18a). To a cold (0 58) soln. (220 ml) ofCuSO 4 ¥ 5 H2O (0.3m) and NaCl
(0.75m), first the soln. of 15 obtained from the previous procedure, and then ascorbic acid (205 mg, 1.6 mmol)
were added under stirring. The mixture was stirred for 1 h at r.t. and then filtered. The solid product obtained
was dried (anh. CaCl2) for 24 h and then processed by flash chromatography (FC) [7] (external diameter of the
column 5 cm, silica gel (0.040 0.063 mm, 170 g), AcOEt/light petroleum ether 6 :4 (40 708)); 50 ml fractions
were collected. The initial ten fractions were discarded and Fr. 11 16 were evaporated under reduced pressure

Helvetica Chimica Acta Vol. 88 (2005)
2279
to give 500 mg ofa mixture that was crystallized from Et 2O to give 18a (160 mg). Crystalline colorless solid. M.p.
156 1588. IR: 1708 (CO). 1H-NMR: 2.19 (s, Me); 2.21 (s, Me); 2.47 (s, Me); 3.91 (s, Me); 5.93 (s, HÀC(4) of
‡
pyrazole); 6.82 7.21 (m, 5 arom. H). MS: 343 (M ). Anal. calc. for C17H18ClN5O: C 59.39, H 5.28, N 20.37;
found: C 59.17, H 5.40, N 20.03.
4,6-Dihydro-1,4,6,8-tetramethyl-3-phenyldipyrazolo[3,4-b:4',3'-d]pyridin-5(3H)-one (16). Fr. 21 26 were
evaporated under vacuum, and the residues crystallized from AcOEt to give 16 (100 mg): Colorless crystalline
solid. M.p. 241 2438. IR: 1649 (CO). 1H-NMR: 2.58 (s, Me); 2.61 (s, Me); 3.09 (s, Me); 4.18 (s, Me); 7.53 (s, 5
‡
arom. H). MS: 307 (M ). Anal. calc. for C17H17N5O: C 66.43, H 5.57, N 22.79; found: C 66.57, H 5.60, N 22.60.
4,6-Dihydro-3,4,6,8-tetramethyl-1-phenyldipyrazolo[4,3-b:4',3'-d]pyridin-5(1H)-one (17). Fr. 32 38 were
evaporated under vacuum, and the residues crystallized from AcOEt to give 17 (90 mg). White crystalline solid.
1
M.p. 220 2228. IR: 1646 (CO). H-NMR: 1.46 (s, Me); 2.61 (s, Me); 3.75 (s, Me); 4.20 (s, Me); 7.57 (br. s, 5
‡
arom. H). MS: 307 (M ). Anal. calc. for C17H17N5O: C 66.43, H 5.57, N 22.79; found: C 66.65, H 5.45, N 22.87.
(3S,4R)- or (3S,4S)-4-Chloro-2,4-dihydro-1',3',5,5'-tetramethyl-2-phenylspiro[3H-pyrazole-3,4'(1'H)-pyr-
rolo[3,4-c]pyrazol]-6'(5'H)-one (18b). The residue obtained by evaporation ofthe mother liquors of Fr. 11
16 were processed by FC [7] (external diameter ofcolumn 3.5 cm, silica gel (0.004 0.063 mm, 70 g), Et 2O/light
petroleum ether 7:3 (40 708)); 50 ml fractions were collected. The first eight fractions were discarded, and
Fr. 17 19 were evaporated to afford a small amount of practically pure 18b. IR: 1705 (CO). 1H-NMR: 2.03 (s,
Me); 2.20 (s, Me); 2.70 (s, Me); 3.86 (s, Me); 5.81 (s, HÀC(4) ofpyrazole); 6.70 7.19 ( m, 5 arom. H). MS: 343
‡
(M ).
4'-Chloro-N,1,3,3'-tetramethyl-1'-phenyl[4,5'-1H-bipyrazole]-5-carboxamide (19). Epimer 18a (80 mg) was
dissolved in 1m KOH in abs. EtOH (5 ml) and the soln. was stirred for 15 h at r.t. The obtained soln. was diluted
with H2O to a volume of25 ml and then extracted with Et 2O (3 Â 25 ml). The combined extracts were dried
(Na2SO4) and evaporated to afford a solid residue. Crystallization from AcOEt/light petroleum ether (40 708)
1
gave compound 19 (60 mg, 75%). Colorless crystalline solid. M.p. 111 1128. IR: 3231 (NH), 1671 (CO). H-
NMR: 1.67 (s, Me); 2.27 (s, Me); 2.60 (s, Me); 3.84 (s, Me); 7.24 7.41 (m, 5 arom. H); 7.9 (br. s, NH (exchanges
‡
very slowly with D2O)). MS: 343 (M ). Anal. calc. for C17H18ClN5O: C 59.39, H 5.28, N 20.37; found: C 59.60, H,
5.41, N 20.21.
X-Ray Crystallography. The crystal data for 16 and 17 are given in Table 1, and significant bond lengths are
listed in Table 2. The intensity data were collected on a CAD4 diffractometer with graphite monochromated
MoKa radiation (l 0.71073 ä). The cell parameters were determined and refined by least-squares fit of 20 high-
angle reflections. The structures were solved by direct methods with Sir-92 [8] and conventional Fourier
synthesis (SHELX-97) [9]. The refinement of the structures was made by full-matrix least-squares on F2. All
non-H-atoms were refined anisotropically. The H-atom positions were detected in a difference Fourier synthesis
and refined with isotropic thermal factors. The supplementary crystallographic data have been deposited with
the Cambridge Crystallographic Data Centre (CCDC deposition numbers 253865 and 253866).
Linear Dichroism (LD) Measurements. The LD spectra ofDNA solns. (4 Â 10À3 m) containing 2 mm NaCl
and 1 mm EDTA were measured in the absence and presence ofexcess 17 on a Jasco J500 CD spectrometer
converted for LD according to Wada and Kozawa [10]. Briefly, a quartz cylinder was immersed in a cylindrical
cell with two quartz windows. The sample soln. was illuminated with plane-polarized light ofincidence
perpendicular to the cell axis. When the inner cylinder rotates, the long, stiff DNA molecules are oriented in the
flow. The LD spectrum is the difference between the absorption spectra recorded with and without cylinder
rotation (i.e., with the molecules oriented randomly or ordered, resp.).
Antiproliferation Assay. Compound 17 was tested in vitro for the antiproliferation activity against the
human NCI-H460 cell line. Cells were suspended at a density of4 Â 105 cells per ml in minimum essential
medium (Eagle MEM, Sigma) supplemented with 10% fetal calf serum (FCS) and antibiotics, transferred
(100 ml per well) to 96-well plate and incubated for 4 d at 378 in a humidified atmosphere containing 5% CO2.
After this incubation time, the cells reached confluence, the medium was removed and replaced with RPMI-
1640 (without phenol red but with FCS, 0.025% glutamine, and antibiotics) with or without test compound and
incubated at 378 for 3 d. At the end of this incubation time, the antiproliferation activity was determined by
means ofthe MTT ((3-(4, 5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide); thiazolyl blue) assay [11]
and expressed as the IC50 value (test concentration at which the cell proliferation was inhibited to a level 50% of
that ofthe untreated control).
We are grateful to Prof. S. Caffieri (Padova University) for the LD measurements, to Dr. D. Schillaci
¡
(Palermo University) for the antiproliferation test and to the Ministero dell×Istruzione, dell×Universita e della
Ricerca (MIUR, Research fund ex 60%) for financial support.

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Helvetica Chimica Acta Vol. 88 (2005)
Table 1. Crystal and Refinement Data for 16 and 17
16
17
Formula
C17H17N5O
307.36
293(2)
0.71073
monoclinic
P21/m
C17H19N5O2
323.36
293(2)
0.71073
monoclinic
P21/n
Molecular weight
Temperature [K]
Wavelength [ä]
Crystal system
Space group
Cell parameters
a [ä]
10.460(2)
7.226(7)
b [ä]
6.898(2)
20.362(8)
c [ä]
10.820(2)
11.421(4)
b [8]
V [ä3]
108.81(5)
739.0(3)
96.74(5)
1668.8(9)
Z
2
4
Calc. density [g cmÀ3
]
1.381
0.091
324
1.287
0.088
688
Absorption coeff. (mmÀ1
F(000)
)
Scan technique
Crystal size [mm]
q range [8]
w/2q
w/2q
0.5 Â 0.5 Â 1
0.3 Â 0.3 Â 1
2.06 24.98
2.00 19.98
Limiting indices
Refls. collected
Unique refls.
12 ꢀ h ꢀÀ 12, 8 ꢀ k ꢀÀ 1, 12 ꢀ l ꢀÀ 12
6 ꢀ h ꢀÀ 6, 19 ꢀ k ꢀ 0, 10 ꢀ l ꢀ 0
1919
1642
1411
1548
Completeness to q
Refinement method
Data, restraints, parameters
Goodness-of-fit on F2
R (I > 2s(I))
99.9%
99.7%
Full-matrix least-squares on F2
1411, 0, 148
1548, 0, 175
0.997
R1 ˆ 0.0554, wR2 ˆ 0.1340
1.038
R1 ˆ 0.0508, wR2 ˆ 0.1280
Table 2. Significant Bond Lengths [ä] for 16 and 17
16
17
N(1)ÀN(2)
N(1)ÀC(9)
N(1)ÀC(8)
N(2)ÀC(7)
C(9)ÀC(8)
C(7)ÀC(8)
C(9)ÀC(7)
N(1)ÀC(1)
N(3)ÀC(13)
C(10)ÀC(12)
C(12)ÀC(13)
C(10)ÀC(9)
O(1)ÀC(13)
N(5)ÀC(11)
N(3)ÀC(8)
N(3)ÀC(16)
N(4)ÀN(5)
N(4)ÀC(12)
C(10)ÀC(11)
N(4)ÀC(18)
C(11)ÀC(17)
1.370(4)
1.352(9)
1.37(1)
1.349(5)
1.308(5)
1.384(5)
1.34(1)
1.39(1)
1.35(1)
1.400(5)
1.426(5)
1.408(5)
1.389(6)
1.445(6)
1.443(5)
1.212(5)
1.333(5)
1.378(5)
1.452(5)
1.344(5)
1.354(5)
1.403(5)
1.454(5)
1.468(6)
1.433(8)
1.36(1)
1.40(1)
1.48(1)
1.43(1)
1.23(1)
1.35(1)
1.40(1)
1.475(9)
1.36(1)
1.34(1)
1.36(1)
1.50(1)
1.46(1)

Helvetica Chimica Acta Vol. 88 (2005)
2281
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Received November 8, 2004