Stereoselective synthesis and single crystal X-ray structures of some sterically congested electron-poor N-vinyl pyrazole derivatives

Article abstract of DOI:10.1515/znb-2008-0109

A one-pot synthesis of sterically congested electron-poor N-vinyl pyrazoles in fairly good yields by the reaction of ethyl 3-phenyl-2-propynoate, pyrazoles and triphenylphosphine is reported. The structures of these compounds were confirmed by IR, ¹H, and ¹³C NMR spectroscopy, and single crystal X-ray structure determination. The structural analysis of the products indicated that the reaction is completely regio- and stereoselective.

Full text of DOI:10.1515/znb-2008-0109

Stereoselective Synthesis and Single Crystal X-Ray Structures of Some
Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives
a
a
a
b
´
Nader Noshiranzadeh , Ali Ramazani , Amir Tofangchi Mahyari , Katarzyna Slepokura ,
and Tadeusz Lisb
a Department of Chemistry, Zanjan University, P O Box 45195-313, Zanjan, Iran
b Faculty of Chemistry, University of Wrocław, 14 Joliot-Curie St., 50-383 Wrocław, Poland
Reprint requests to Dr. A. Ramazani. Fax: +98 241 5283100. E-mail: aliramazani@yahoo.com
Z. Naturforsch. 2008, 63b, 65 – 70; received August 5, 2007
A one-pot synthesis of sterically congested electron-poor N-vinyl pyrazoles in fairly good yields
by the reaction of ethyl 3-phenyl-2-propynoate, pyrazoles and triphenylphosphine is reported. The
1
structures of these compounds were confirmed by IR, H, and 13C NMR spectroscopy, and single
crystal X-ray structure determination. The structural analysis of the products indicated that the reac-
tion is completely regio- and stereoselective.
Key words: 3-Phenyl-2-propynoate, Vinyltriphenylphosphonium Salts, Crystal Structure,
Phosphorus Ylide, N-Vinyl Pyrazoles
Introduction
convulsant, antihistaminic, antibiotic and anti-depress-
ant properties [1 – 10].
Pyrazole derivatives are in general well-known
nitrogen-containingheterocyclic compounds, and vari-
ous procedures have been developed for their syntheses
[1 – 3]. The chemistry of pyrazole derivatives has been
the subject of much interest due to their importance for
various applications and their widespread potential and
proven biological and pharmacological activities such
as anti-inflammatory, antipyretic, analgesic, antimicro-
bial, antiviral, antitumor, antifungal, pesticidal, anti-
β-Additions of nucleophiles to the vinyl group of
vinylphosphonium salts leading to the formation of
new alkylidenephosphoranes has attracted much at-
tention as a very convenient and synthetically useful
method in organic synthesis [11 – 14].
Acetylenic esters are reactive systems and take
part in many chemical syntheses as Michael accep-
tors [15 – 19]. In recent years, we have established a
one-pot method for the synthesis of stabilized phos-
phorus ylides [15 – 24]. In this paper, we wish to de-
scribe the preparation of sterically congested electron-
poor N-vinyl pyrazoles from a 3-phenyl-2-propynoate
and pyrazoles in the presence of triphenylphosphine in
fairly good yields.
Results and Discussion
The reaction of ethyl 3-phenyl-2-propynoate (2)
with pyrazole derivatives 4 in the presence of tri-
phenylphosphine (1) proceeded spontaneously at r. t.
in CH2Cl2 and was finished within 72 h. Based on
TLC monitoring of the reaction and NMR analyses
of the products, in this reaction, Z stereoisomers 8a,
8b and 8c were observed only and therefore, the re-
action is completely regio- and stereoselective. A re-
action mechanism is proposed in Scheme 1. We re-
duced the amount of triphenylphosphine to 50 % of
Scheme 1.
0932–0776 / 08 / 0100–0065 $ 06.00 © 2008 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
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66
N. Noshiranzadeh et al. · Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives
Table 1. Crystal data and structure refinement details for 8a
and 8b.
8a
8b
Crystal data
Empirical formula
C
16H18N2O2
C21H20N2O2
332.39
Formula weight, g mol−1
Crystal system, space group
270.32
— monoclinic, P21/n —
˚
a, A
11.044(3)
7.970(2)
21.427(5)
10.780(3)
108.78(3)
1742.9(8)
4
1.267
0.082
704
˚
b, A
7.944(2)
17.605(3)
96.24(3)
1535.4(6)
4
1.169
0.078
˚
c, A
β, deg
3
˚
V, A
Z
Dcalc, g cm−3
µ, mm−1
F(000), e
576
Crystal size, mm3
Crystal color and form
0.48×0.46×0.26 0.50×0.34×0.17
colorless block colorless plate
Data collection
Diffractometer
Data collection method
Monochromator
Radiation type
T, K
— Kuma KM4CCD —
— ω scans —
— graphite —
˚
— MoKα (λ = 0.71073 A) —
240(2)
100(2)
θ Range, deg
h, k, l Ranges
3.17 – 29.00
−14 ≤ h ≤ 15
−10 ≤ k ≤ 9
−24 ≤ l ≤ 24
16548
3.30 – 28.00
−10 ≤ h ≤ 8
−28 ≤ k ≤ 27
−12 ≤ l ≤ 14
14709
Measured reflections
Independent reflections
Observed refl. [I ≥ 2σ(I)]
3964
2338
4142
3489
Refinement
Fig. 1. The molecular structures of compounds 8a (a) and
8b (b) showing the atom numbering schemes. The in-
tramolecular C(5)–H(5)···O(2) and C(7)–H(7)···N(1) con-
tacts forming S(5) and S(6) motifs, respectively, as well as
C(15)–H(15A)···O(1) in 8b are shown with dotted lines. Dis-
placement ellipsoids are drawn at the 30 % (for 8a) and 50 %
(for 8b) probability level.
Refinement on
F2
F2
Data/restraints/parameters
3964/0/184
R1 = 0.0554
wR2 = 0.1411
R1 = 0.1044
wR2 = 0.1615
1.063
4142/0/306
R1 = 0.0425
wR2 = 0.0999
R1 = 0.0533
wR2 = 0.1057
1.054
R[Fo ≥ 2σ(Fo2)]a
2
R (all data)a
GooF = S
Weighting parameter a/b
∆ρmax/min, e A
0.0831/0.0
0.0515/0.5418
0.27/−0.22
mole ratio. In all cases where we used triphenylphos-
phine as a catalyst in the range of 50 % to 100% of
molar ratio, the reaction time amounted to 72 hours. In
all cases where we used triphenylphosphine as a cata-
lyst in the range below 50 % of mole ratio, the reaction
time was longer than 72 hours. The reaction proceeded
smoothly and cleanly and no side reactions were ob-
served. In the absence of triphenylphosphine no prod-
ucts were observed. The structures of 8a – c were de-
duced from their IR, 1H and 13C NMR spectra and sin-
gle crystal X-ray structure determination.
−3
˚
0.17/−0.13
ꢀ
a
R1 = ΣꢀFo| − |Fcꢀ/Σ|Fo|; wR2 = Σ[w(Fo −Fc2)2]/Σ[w(Fo2)2];
2
weighting scheme: w = 1/[σ2(Fo2)+(aP)2 +bP], where P = (Fo
2Fc2)/3.
+
2
to that observed in their close analogs described by
us previously [23, 25]. Like in these compounds, two
well defined planes (with the atoms N(1) and C(4) be-
ing common) may be distinguished in the molecules of
8a and 8b. These are the ethyl (2Z)-2-amino-3-phen-
ylacrylate moiety (forming plane 1 with r. m. s. devi-
˚
˚
ation of fitted atoms = 0.155 A in 8a and 0.163 A in
Description of the crystal structures of 8a and 8b
8b) and the rest of the molecule (plane 2 with r. m. s. =
˚
˚
0.007 A in 8a and 0.048 A in 8b). The atoms which
deviate the most from these planes in 8a are O(1), be-
The crystals of 8a and 8b are built up from mol-
ecules of structures shown in Fig. 1. The summary of
the experimental details are given in Table 1. The over-
all structures of the presented compounds are similar
˚
ing displaced by 0.332(2) A from plane 1, and C(13)
deviating by 0.012(2) A from plane 2. In 8b these are
˚
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N. Noshiranzadeh et al. · Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives
67
Table 2. Selected
8a
8b
8a
8b
interatomic
dis-
O(1)–C(3)
O(2)–C(2)
O(2)–C(3)
N(1)–N(2)
N(1)–C(4)
N(1)–C(14)
1.205(2)
1.458(2)
1.329(2)
1.364(2)
1.428(2)
1.352(2)
1.212(2) N(2)–C(12)
1.462(2) C(3)–C(4)
1.340(2) C(4)–C(5)
1.369(2) C(5)–C(6)
1.429(2) C(12)–C(13)
1.369(2) C(13)–C(14)
1.331(2)
1.492(2)
1.330(2)
1.469(2)
1.394(2)
1.368(2)
1.340(2)
1.492(2)
1.343(2)
1.468(2)
1.413(2)
1.372(2)
˚
tances (A), valence
angles (deg) and
torsion angles (deg)
in 8a and 8b.
C(14)–N(1)–N(2)
N(2)–N(1)–C(4)
C(14)–N(1)–C(4)
112.28(13)
120.15(12)
127.57(13)
112.50(9) C(12)–N(2)–N(1)
118.08(9) C(4)–C(5)–C(6)
128.83(10)
104.56(11)
130.37(14)
104.18(9)
129.25(11)
C(4)–N(1)–N(2)–C(12) −179.3(2)
−172.2(1)
170.6(1)
179.8(1)
61.2(2)
O(2)–C(3)–C(4)–C(5)
O(2)–C(3)–C(4)–N(1)
N(1)–C(4)–C(5)–C(6)
C(4)–C(5)–C(6)–C(7)
N(2)–C(12)–C(16)–C(17)
−17.2(2)
167.0(2)
−1.2(3)
−4.1(3)
—
−10.8(2)
167.2(1)
4.3(2)
19.5(2)
−5.2(2)
C(3)–O(2)–C(2)–C(1)
C(2)–O(2)–C(3)–C(4)
N(2)–N(1)–C(4)–C(5)
179.5(2)
177.3(2)
91.6(2)
N(1)–N(2)–C(12)–C(16) −179.6(2)
179.5(1)
tion to the vinyl carbon atom C(5) in both 8a and 8b as
also found for most of structurally related compounds
[23, 25, 26].
The short C(5)···O(2) and C(7)···N(1) intramolec-
ular contacts in 8a and 8b, also observed before
[23, 25, 26], may indicate the presence of weak in-
tramolecular hydrogen interactions: C(5)–H(5)···O(2)
and C(7)–H(7)···N(1), giving rise to five-membered
S(5) and six-membered S(6) motifs, respectively (see
Table 3 for geometrical details). Both of them are
formed in plane 1 and stabilize the molecular struc-
tures of the compounds. There is another contact,
C(15)–H(15A)···O(1), observed in the molecule of
8b, which results in a seven-membered intramolecu-
lar motif. It is to note here that most of the Z geo-
metrical isomers of similar structures reported so far
[23, 25, 26] also revealed some deviations from the pla-
narity of the fragment defined here as plane 1; they
usually showed the phenyl group slightly twisted. That
is reflected in the value of the C(4)–C(5)–C(6)–C(7)
torsion angle (Table 2), which is significantly larger
in compound 8b than in 8a and in the tetrahydro-
phthalimidyl and 1,3-dioxo-1,3-dihydro-2H-isoindol-
yl derivatives [23, 25].
Fig. 2. Comparison of molecular structures of compounds 8a
(solid line) and 8b (open line). The common reference points
are O(1), O(2) and C(3).
˚
N(1) and N(2) deviating by 0.407(1) A from plane 1
˚
and by 0.093(1) A from plane 2, respectively.
The dihedral angles between the least-squares
planes 1 and 2 are quite different in the presented com-
pounds. They amount to 89.3(1)◦ in 8a and 62.2(1)◦
in 8b and reveal that the two planes are almost per-
pendicular to each other in 8a (like in the tetrahydro-
phthalimidyl derivative [23]), and not perpendicular
in 8b (like in the 1,3-dioxo-1,3-dihydro-2H-isoindolyl
derivative [25]). The differences in the molecular struc-
tures of compounds 8a and 8b are shown in Fig. 2.
As it was observed for close analogs of the de-
As stated above, the overall conformation of the
scribed compounds reported by us previously [23, 25], molecules 8a and 8b may be stabilized by the
as well as in most of the compounds with related intramolecular interactions C(5)–H(5)···O(2), C(7)–
structures, i. e. bearing different substituents at atom H(7)···N(1) and C(15)–H(15A)···O(1) (for 8b), result-
N(1) and different ester groups (usually –C(O)OMe ing in S(5), S(6) and S(7) motifs, respectively. The two
and –C(O)OEt), deposited at the Cambridge Structural former ones are formed in plane 1, but the C(15)–
Database [26], the molecules of 8a and 8b adopt Z H(15A)···O(1) contact, observed only in the molecule
geometry with respect to the double bond C(4)–C(5), of 8b, connects the two planes of that molecule and
which is reflected in the value of the torsion angle is accompanied by their non-perpendicular mutual ori-
N(1)–C(4)–C(5)–C(6) of −1.2(3)◦ in 8a and 4.3(2)◦ entation, with the dihedral angle between them close
in 8b (Table 2). The carbonyl oxygen atom O(1) in the to 60◦ (see Figs. 1 and 2). It is to note that in both 8a
ester group is in antiperiplanar conformation in rela- and 8b, the H(7) atom is in close contact with N(2)
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68
N. Noshiranzadeh et al. · Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives
Table 3. Geometry of pro-
posed hydrogen bonds and C–
˚
˚
˚
˚
D–H···A
D−H (A)
H···A (A)
D···A (A)
D−H···A (deg)
Offset (A)
compound 8a
H···O/N/π close contacts for 8a
C(5)–H(5)···O(2)
C(7)–H(7)···N(1)
C(9)–H(9)···O(1)i
C(7)–H(7) ···Cg(1)
C(16)–H(16A)· ··Cg(1)ii
compound 8b
C(5)–H(5)···O(2)
C(7)–H(7)···N(1)
C(10)–H(10)···O(1)iii
C(13)–H(13)···N(2)iv
C(15)–H(15A)···O(1)
C(19)–H(19) ···O(1)v
C(7)–H(7)· ··Cg(1)
0.94
0.94
0.94
0.94
0.97
2.35
2.38
2.53
2.51
2.96
2.736(2)
3.014(2)
3.445(2)
3.358(2)
3.868(2)
104
124
166
150
156
–
–
–
0.84
0.82
a
˚
and 8b (A, deg) .
a
i
Symmetry codes: x − 1, y, z;
0.99(2)
0.98(2)
0.96(2)
0.95(2)
1.00(2)
0.97(2)
0.98(2)
2.38(2)
2.43(2)
2.52(2)
2.46(2)
2.64(2)
2.46(2)
2.45(2)
2.757(2)
2.998(2)
3.344(2)
3.351(2)
3.123(2)
3.344(2)
3.209(2)
102(1)
117(1)
144(2)
156(2)
109(1)
152(2)
134(2)
–
–
–
–
–
–
0.62
ii
iii
−x + 2, −y, −z + 1;
x +
x +
iv
1/2, −y + 3/2, z − 1/2;
v
1/2, −y + 3/2, z + 1/2; −x +
1/2, y + 1/2, −z + 3/2; Cg(1) is
the centroid of the pyrazolyl ring
[N(1)–N(2)–C(12)–C(13)–C(14)].
Fig. 3. A fragment of infinite chains formed along the a axis
in the crystal of 8a with adjacent molecules joined by C(9)–
H(9)· ··O(1)i hydrogen bonds (dashed lines). Intramolecular
C–H···O/N close contacts are shown with dotted lines. Sym-
metry codes are given in Table 3.
Fig. 4. The arrangement of the molecules in the crystal lat-
tice of 8b. Intermolecular C–H···O/N bonds are shown with
dashed lines, intramolecular with dotted lines. Symmetry
codes are given in Table 3.
˚
(with H···N distances of about 2.6 A). Besides, the
same H(7) atom is involved in intramolecular C(7)–
H(7)···π[Cg(1)] interaction in the crystals of both com-
pounds (see Table 3 for details).
Conclusions
In conclusion, we have developed a convenient, one-
pot regio- and stereoselective method for preparing
sterically congested electron-poor N-vinyl pyrazoles
(8a – c) utilizing in situ generation of vinyl phospho-
nium salts. Other aspects of this process are under in-
vestigation. The X-ray structures of 8a and 8b (in their
Z isomeric forms) reveal that in the solid state, the
overall structure of the compounds is similar, but with
some differences in the mutual orientation of the two
main planes of the molecules and in the twisting of
the phenyl ring in the phenylacrylate moiety. Besides,
the connectivity pattern of the molecules via hydrogen
bonds is different in the two structures.
The molecules in the crystal of compound 8a are
joined to each other by C(9)–H(9)···O(1)i interactions
to form infinite chains along the a axis (Fig. 3; sym-
metry codes are given in Table 3). Two adjacent chains
are arranged in the crystal lattice by means of C(16)–
H(16A)···π[Cg(1)ii] interactions giving rise to ribbons
parallel to the a axis.
The packing diagram in the crystal of 8b is
of quite different type. The carbonyl oxygen atom
O(1) in the ester group, beside the intramolecu-
lar C(15)–H(15A)···O(1) contact, is also involved in
two additional intermolecular interactions of the C–
H···O type. Atom O(1) accepts atoms H(10) and
H(19) of the phenyl groups of two different adja-
cent molecules, which gives rise to trifurcated, four-
centered C(15)–H(15A)···O(1), C(10)–H(10)···O(1)iii,
C(19)–H(19)···O(1)v contacts. The latter interactions,
in combination with C(13)–H(13)···N(2)iv, result in
a three-dimensional network of hydrogen bonds, ob-
served in the crystal lattice of compound 8b (Fig. 4).
Experimental Section
Melting points were measured on an Electrothermal 9100
apparatus and are uncorrected. Elemental analyses were per-
formed using a Heraeus CHN-O-Rapid analyzer. IR spectra
were recorded on a Mattson-1000 FTIR spectrophotometer.
1H and 13C NMR spectra were measured with a Bruker Spec-
trospin spectrometer at 250 and 62.5 MHz, respectively.
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N. Noshiranzadeh et al. · Some Sterically Congested Electron-poor N-Vinyl Pyrazole Derivatives
69
◦
Preparation of ethyl (Z)-2-(3,5-dimethyl-1H-pyrazol-1-yl)-3- ether (1 : 4) solution (20 – 25 C). The crystals were filtered
phenyl-2-propenoate (8a)
off, washed with a cold mixture of dichloromethane/light
petroleum ether (1 : 4) and dried at r. t. (m. p. 77.0 –
80.0 ◦C).
General procedure
To a magnetically stirred solution of triphenylphosphine
(0.262 g, 1 mmol) and 3,5-dimethyl-1H-pyrazole (0.096 g,
1 mmol) in dichloromethane (5 mL) was added dropwise a
mixture of ethyl 3-phenyl-2-propynoate (0.17 mL, 1 mmol)
in dichloromethane (2 mL) at −10 ◦C over 15 min. The mix-
ture was allowed to warm up to r. t. and stirred for 72 hrs
at r. t. The solvent was removed under reduced pressure
and the viscous residue was purified by flash column chro-
matography (silica gel; petroleum ether/ethyl acetate). The
solvent was removed under reduced pressure and the prod-
uct was obtained as white crystals. Yield: 0.216 g (80 %);
m. p. 52.0 – 55.0 ◦C. – IR (KBr): ν = 3096, 2984, 1715,
1646 cm−1. – 1H NMR (CDCl3): δ = 1.32 (t, 3 H, 3J =
7.2 Hz, CH3 of OEt), 1.96 and 2.32 (2 s, 6 H, 2 CH3),
4.32 (q, 2 H, 3J = 7.2 Hz, OCH2), 5.99 (s, 1 H, pyrazole
ring), 6.85 – 7.35 (m, 5 H, arom.), 7.92 (s, 1 H, =CH). –
13C NMR (CDCl3): δ = 10.73, 13.77 and 14.23 (3 CH3),
61.73 (OCH2), 106.21, 128.79, 130.45, 130.76 and 140.14
(7 CH); 127.21, 131.91, 140.28 and 149.95 (4 C); 164.25
(C=O of ester). – C16H18N2O2 (270.33): calcd. C 71.09,
H 6.71, N 10.36; found C 71.01, H 6.79, N 10.42.
Selected data for ethyl (Z)-2-(3,5-diphenyl-1H-pyrazol-1-yl)-
3-phenyl-2-propenoate (8c)
Colorless oil. Yield: 0.24 g (60 %). – IR (neat): ν = 3061,
2984, 1723, 1646 cm−1. – 1H NMR (CDCl3): δ = 1.20 (t,
3H, 3J = 7.2 Hz, CH3 of OEt), 4.24 (q, 2 H, 3J = 7.2 Hz,
OCH2), 6.90 (s, 1 H, pyrazole ring), 7.02 – 7.52 (m, 15 H,
arom.), 7.95 (s, 1 H, =CH). – 13C NMR (CDCl3): δ =
14.03 (CH3), 61.74 (OCH2), 104.18, 125.97, 127.77, 128.10,
128.40, 128.48, 128.60, 128.74, 130.60, 130.73 and 140.41
(17 CH), 128.30, 130.00, 131.99, 133.10, 145.97 and 152.90
(6 C), 164.25 (C=O of ester). – C26H22N2O2 (394.47): calcd.
C 79.16, H 5.62, N 7.10; found C 79.07, H 5.56, N 7.16.
Crystal structure determination of 8a and 8b
The crystallographic measurements for crystals of 8a
and 8b were performed on a κ-geometry Kuma KM4CCD
automated four-circle diffractometer with graphite-mono-
chromatized MoKα radiation. The data were collected at
240(2) and 100(2) K for 8a and 8b, respectively, using the
Oxford Cryosystems cooler. Crystals of 8a cracked at tem-
peratures below 235 K. A summary of the conditions for
the data collection and the structures refinement parameters
are given in Table 1. The data were corrected for Lorentz
and polarization effects. Data collection, cell refinement,
and data reduction and analysis were carried out with the
KM4CCD software CRYSALIS CCD and CRYSALIS RED,
respectively [27]. The structures were solved by Direct Meth-
ods using SHELXS-97 [28] and refined by a full-matrix least-
squares technique using SHELXL-97 [29] with anisotropic
displacement parameters for non-H atoms. All H atoms in
8b were found in difference Fourier maps and were refined
isotropically. The H atoms in 8a were also found in differ-
ence Fourier maps, but in the final refinement cycles, they
were treated as riding atoms, with C–H distances of 0.94 –
Preparation of single crystals of ethyl (Z)-2-(3,5-dimethyl-
1H-pyrazol-1-yl)-3-phenyl-2-propenoate (8a)
Colorless single crystals of 8a were obtained from slow
evaporation of its dichloromethane/light petroleum ether
(1 : 1) solution (20 – 25 ◦C). The crystals were filtered
off, washed with a cold mixture of dichloromethane/light
petroleum ether (1 : 1) and dried at r. t. (m. p. 52.0 – 55.0 ◦C).
Selected data for ethyl (Z)-2-(5-methyl-3-phenyl-1H-
pyrazol-1-yl)-3-phenyl-2-propenoate (8b)
W◦hite crystals. Yield: 0.23 g (68 %); m. p. 77.0 –
80.0 C. – IR (KBr): ν = 2992, 2923, 1715, 1646 cm−1. –
1H NMR (CDCl3): δ = 1.38 (t, 3H, 3J = 7.2 Hz, CH3 of
OEt), 2.12 (3 H, 1 s, CH3), 4.38 (q, 2 H, 3J = 7.2 Hz,
OCH2), 6.60 (s, 1 H, pyrazole ring), 6.99 (d, 2 H, 3J = 7.0 Hz,
arom.), 7.91 (d, 2 H, 3J = 7.5 Hz, arom.), 7.27 – 7.48 (m, 6 H,
arom), 8.05 (s, 1 H, =CH). – 13C NMR (CDCl3): δ = 10.97
and 14.28 (2 CH3), 61.88 (OCH2), 103.76, 125.87, 127.81,
128.53, 128.92, 130.58, 130.97 and 140.73 (12 CH), 127.21,
131.81, 133.4, 141.05 and 152.56 (5 C), 164.25 (C=O of es-
ter). – C21H20N2O2 (332.4): calcd. C 75.88, H 6.06, N 8.44;
found C 75.95, H 6.00, N 8.50.
˚
0.98 A, and with Uiso values of 1.5 Ueq(C) for CH3 groups,
and 1.2 Ueq(C) for CH2 and CH groups. All figures were
made using the XP program [30].
Crystallographic data for the structures have been de-
posited with the Cambridge Crystallographic Data Centre,
CCDC-656361 (8a) and CCDC-656362 (8b). Copies of the
data can be obtained free of charge via www.ccdc.cam.ac.uk/
data request/cif.
Preparation of single crystals of ethyl (Z)-2-(5-methyl-3-
phenyl-1H-pyrazol-1-yl)-3-phenyl-2-propenoate (8b)
Acknowledgement
The Iranian authors are thankful to the “Sandoogh
Colorless single crystals of 8b were obtained from slow Hemayate as Pajuoheshgharane Keshvare Iran” for partial
evaporation of its saturated dichloromethane/light petroleum support of this work.
Unauthenticated
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70
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