Reaction of 1-aryl-3-methylpyrazol-5-ones with 2-cyanoaryldiazonium bisulfates

Article abstract of DOI:10.1007/s10593-005-0124-5

2-Cyanoaryldiazonium bisulfates, obtained by the action of nitrosyl sulfuric acid on isatin 3-hydrazone and its 5-bromo and 5-nitro derivatives, couple with 1-aryl-3-methylpyrazol-5-ones and form 4-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones. It

Full text of DOI:10.1007/s10593-005-0124-5

Chemistry of Heterocyclic Compounds, Vol. 41, No. 2, 2005
REACTION OF 1-ARYL-3-METHYL-
PYRAZOL-5-ONES WITH 2-CYANOARYL-
DIAZONIUM BISULFATES
1
1
2
2
M.-G. A. Shvekhgeimer , O. A. Ushakova , V. V. Nesterov , and M. Yu. Antipin
2
-Cyanoaryldiazonium bisulfates, obtained by the action of nitrosyl sulfuric acid on isatin 3-hydrazone
and its 5-bromo and 5-nitro derivatives, couple with 1-aryl-3-methylpyrazol-5-ones and form
-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones. It was established on the basis of data of IR,
4
1
UV, and H NMR spectra and of X-ray structural analysis that the coupling products exist in the
hydrazone form stabilized by an intramolecular hydrogen bond.
Keywords: 4-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones, 1-aryl-3-methylpyrazol-5-ones,
2
-cyanoaryldiazonium bisulfates, coupling reaction.
Aryldiazonium salts react readily with compounds containing an activated methylene group with the
formation of arylhydrazones.
R1
_
+
ArN2 X +
R
CH2
ArNHN=C–R1
R
+ HX
Of the heterocyclic compounds with an activated CH group capable of a coupling reaction with
2
aryldiazonium salts, some of the most studied are the 1-aryl-3-R-pyrazol-5-ones [1].
The products of coupling aryldiazonium salts with 1-aryl-3-R-pyrazol-5-ones may exist in four
tautomeric forms 1a-d. Preference must be given to structures 1a and 1b, stabilized by an intramolecular
hydrogen bond.
Ar
Ar
R
Ar
N
O
R
Ar
N
O
R
N
R
N
N
N
N
H
N
H
N
N
NH
N
N
N
O
N
O
N
Ar1
Ar1
Ar1
Ar1
1
a
1b
1c
1d
_
_________________________________________________________________________________________
1
2
Moscow A. N. Kosygin State Textile University, Moscow 117918, Russia; e-mail: office@msta.ac.ru.
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow 117813; e-
mail: xray@xray.ineos.ac.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 210-215,
February, 2005. Original article submitted September 13, 2001; revision submitted February 3, 2004.
0
009-3122/05/4102-0181©2005 Springer Science+Business Media, Inc.
181

The use of physicochemical methods of investigation for establishing the structures of organic
compounds has enabled strict and unequivocal determination of the tautomeric form in which the products of
coupling aryldiazonium salts with 1-aryl-3-R-pyrazol-5-ones exist.
1
5
13
It was established by data of N and C NMR spectroscopy [2] and by X-ray structural analysis [3-8]
that these coupling products, as a rule, exist in the tautomeric form 1a.
Until our work there was no information in the literature on the synthesis and structure determination of
compounds 1 in which the group Ar might be phenyl containing the strong electron-withdrawing group CN in
the position ortho to the –NH–N= grouping. However, the presence of such a group in conjugation with the
remaining portion of the molecule may influence the tautomeric equilibrium.
In the present work we have synthesized 4-arylhydrazones of 1-aryl-3-methylpyrazole-4,5-diones 2 by
the coupling reaction of 1-aryl-3-methylpyrazol-5-ones 3 with 2-cyanobenzenediazonium bisulfates 4. The latter
were obtained by treating 3-hydrazones of isatin and its 5-bromo and 5-nitro derivatives 5 with nitrosyl sulfuric
acid by the procedure developed by us in [9].
R
N
O
NH2
R
CN
NaNO , H SO , AcOH
2
2
4
_
N
+
N
2
HSO4
H
4
5
R
CN
Me
N
O
Me
N
O
N
N
H
Ar
3
N
N
Ar
2
a–i
2
a R = H, Ar = Ph; b R = H, Ar = 4-HO
Ar = 4-MeC ; e R = Br, Ar = 4-HO SC
Ar = 4-MeC ; h R = NO , Ar = 4-HO
3
SC
6
H
4
; c R = Br, Ar = Ph; d R = H,
2
, Ar = Ph; g R = NO ,
6
H
4
3
6
H
4
; f R = NO
2
6
H
4
2
3
SC ; i R = Br, Ar = 4-MeC H
6
H
4
6 4
The coupling of bisulfates 4 with 1-aryl-3-methylpyrazol-5-ones 3 takes place readily, the corresponding
hydrazones 2 are formed in 43-94% yield at the usual temperature in aqueous alcoholic medium. Analysis of the
1
H NMR spectra of compounds 2a-c confirmed that these compounds are in the hydrazone form in DMSO
solution.
An X-ray structural investigation of hydrazones 2a and 2b was carried out to establish unequivocally the
structure of the products of coupling aryldiazonium bisulfates 4 with 1-aryl-3-methylpyrazol-5-ones 3. The
results are shown in Figs. 1 and 2. Bond lengths and valence angles for compounds 2a and 2b are given in
Tables 1 and 2.
Crystals of the molecules of the studied compounds 2 exist in the hydrazone tautomeric form. The
pyrazole ring is planar (planarity is achieved with a precision of ±0.003 Å for compounds 2a and 2b), the
substituents are practically coplanar with this plane. The dihedral angles between the plane of the pyrazolone and
the planes of the benzene rings C(1)–C(2)–C(3)–C(5)–C(6)–C(7) and C(12)–C(13)–C(14)–C(15)–C(16)–C(17)
were 167.3 and 173.9° for compound 2a and 162.0 and 168.5° for compound 2b respectively.
Intramolecular hydrogen bonds were detected in the molecules of the studied compounds at
O(1)···H–N(4) with parameters O(1)···N(4) 2.768(2), O(1)···HN(4) 2.02(2), N(4)–H 0.96(2) Å, angle
N(4)–H···O(1) 134(1)° for compound 2a and O(1)···N(4) 2.757(2), O(1)···HN(4) 2.03(2), N(4)–H 0.93(2) Å,
angle N(4)–H···O(1) 133(1)° for compound 2b. We note that these hydrogen bonds close a practically planar six-
membered ring in the molecules. The remaining geometric parameters in the molecules studied have the usual
values [10].
1
82

Fig. 1. General form of the 2a molecule (the intramolecular hydrogen bond is shown dotted).
Fig. 2. General form of the 2b molecule (the intramolecular hydrogen bond is shown dotted).
TABLE 1. Bond Lengths (d) in the Structures of Compounds 2a and 2b
d, Å
d, Å
Bond
Bond
2
a
2b
2a
2b
O(1)–C(8)
N(1)–C(8)
N(1)–C(7)
N(1)–N(2)
N(2)–C(10)
N(3)–C(9)
N(3)–N(4)
N(4)–C(12)
N(5)–C(18)
C(1)–C(2)
C(1)–C(7)
C(2)–C(3)
C(3)–C(5)
1.239(2)
1.379(2)
1.421(2)
1.431(2)
1.305(2)
1.312(2)
1.321(2)
1.405(2)
1.154(2)
1.387(3)
1.393(3)
1.388(3)
1.398(3)
1.232(2)
1.370(2)
1.418(2)
1.411(2)
1.296(2)
1.303(2)
1.315(2)
1.396(2)
1.146(2)
1.383(2)
1.389(2)
1.394(2)
1.389(2)
C(3)–C(4)
—
1.499(2)
1.386(2)
1.389(2)
1.464(2)
1.439(2)
1.483(2)
1.394(2)
1.395(2)
1.377(2)
1.387(2)
1.384(2)
1.395(2)
1.442(2)
C(5)–C(6)
1.393(3)
1.394(3)
1.470(3)
1.443(2)
1.485(3)
1.402(3)
1.404(2)
1.380(3)
1.393(3)
1.381(3)
1.404(3)
1.438(3)
C(6)–C(7)
C(8)–C(9)
C(9)–C(10)
C(10)–C(11)
C(12)–C(13)
C(12)–C(17)
C(13)–C(14)
C(14)–C(15)
C(15)–C(16)
C(16)–C(17)
C(17)–C(18)
1
83

TABLE 2. Valence Angles (ω) in the Structures of Compounds 2a and 2b
ω, deg.
ω, deg.
Angle
Angle
2
a
2b
2a
2b
C(8)–N(1)–C(7)
C(8)–N(1)–N(2)
C(7)–N(1)–N(2)
C(10)–N(2)–N(1)
C(9)–N(3)–N(4)
N(3)–N(4)–C(12)
C(2)–C(1)–C(7)
C(1)–C(2)–C(3)
C(2)–C(3)–C(5)
C(5)–C(3)–C(4)
C(2)–C(3)–C(4)
C(6)–C(5)–C(3)
C(5)–C(6)–C(7)
C(1)–C(7)–C(6)
C(1)–C(7)–N(1)
C(6)–C(7)–N(1)
O(1)–C(8)–N(1)
O(1)–C(8)–C(9)
130.4(2)
111.5(1)
118.1(1)
107.5(1)
117.1(2)
119.8(2)
119.1(2)
121.2(2)
119.3(2)
—
28.9(1)
112.2(1)
118.9(1)
107.4(1)
116.6(1)
120.2(1)
119.5(2)
121.6(2)
117.6(2)
120.8(2)
121.7(2)
121.9(2)
119.3(2)
120.1(2)
119.5(1)
120.4(2)
128.6(2)
127.7(1)
N(1)–C(8)–C(9)
104.0(2)
125.9(2)
127.9(2)
106.3(2)
110.7(2)
122.3(2)
127.0(2)
119.1(2)
121.6(2)
119.3(2)
119.7(2)
121.2(2)
119.9(2)
19.6(2)
103.8(1)
126.0(2)
128.2(1)
105.8(1)
110.9(1)
122.5(1)
126.6(2)
119.5(2)
121.5(2)
119.0(2)
119.5(1)
121.2(2)
119.9(2)
119.3(2)
120.5(2)
119.4(1)
120.0(1)
178.2(2)
N(3)–C(9)–C(10)
N(3)–C(9)–C(8)
C(10)–C(9)–C(8)
N(2)–C(10)–C(9)
N(2)–C(10)–C(11)
C(9)–C(10)–C(11)
C(13)–C(12)–C(17)
C(13)–C(12)–N(4)
C(17)–C(12)–N(4)
C(14)–C(13)–C(12)
C(13)–C(14)–C(15)
C(16)–C(15)–C(14)
C(15)–C(16)–C(17)
C(12)–C(17)–C(16)
C(12)–C(17)–C(18)
C(16)–C(17)–C(18)
N(5)–C(18)–C(17)
—
120.3(2)
119.5(2)
120.7(2)
119.4(2)
119.9(2)
128.6(2)
127.4(2)
120.4(2)
119.0(2)
120.5(2)
177.0(2)
EXPERIMENTAL
The IR spectra were recorded on a Specord M 80 (KBr disks), and the UV spectra on a Uvidek 610
1
spectrophotometer in alcohol solution. The H NMR spectra were obtained on a Bruker AM 300 (300 MHz)
instrument in solutions of DMSO-d –CCl as the internal standard.
6
4
X-ray Structural Investigations of Compounds 2a and 2b. Experiments were carried out at -163°C on
a SMART 1000 CCD diffractometer (λMoKα = 0.71073 Å, graphite monochromator, ω-scanning with a step of
0
.3°, exposure time 15 sec). Structures were solved by the direct method, revealing all the non-hydrogen atoms,
and were refined by a full-matrix least squares method in an anisotropic approach for the non-hydrogen atoms.
The hydrogen atoms were made apparent by Fourier difference syntheses and were refined isotropically. All
calculations were carried out with SAINT [11] and SHELXTL-97 [12] (PC version) programs.
The crystals of compound 2a were triclinic, at -163°C a = 7.372(3), b = 9.720(4), c = 11.193(4) Å;
3
3
α = 108.44(1), β = 104.73(1), γ = 99.91(1)°; V = 708(1) Å ; d = 1.424 g/cm ; Z = 2; space group P1. The final
calc
values of the reliability factors R = 0.059 for 2236 reflections with I >2σ and R = 0.1692 for 4110 reflections.
1
w
The crystals of 2b were triclinic, at -163°C a = 7.490(2), b = 10.574(3), c = 10.657(3) Å; α = 109.04(1),
3
3
β = 102.97(1), γ = 101.46(1)°; V = 743(1) Å ; dcalc = 1.419 g/cm ; Z = 2, space group P1. The final values of the
reliability factors were R = 0.058 for 2455 reflections with I >2σ and R = 0.2203 for 4326 reflections.
1
w
4
-(2-Cyanophenyl)hydrazone of 3-Methyl-1-phenylpyrazole-4,5-dione (2a). Finely powdered sodium
nitrite (1.4 g, 0.02 mol) was added gradually with stirring during 30 min to conc. H SO cooled to 0-5°C. Isatin
2
4
3
-hydrazone (5, R = H) (1 g, 0.0062 mol) was then added gradually during 15 min to the resulting nitrosyl
sulfuric acid, periodically adding glacial acetic acid (8 ml). The resulting mixture was stirred at 5-10°C for 30
min, and poured into a mixture of water (50 ml) and ice (50 g). A solution of 3-methyl-1-phenylpyrazol-5-one
(
1.1 g, 0.0063 mol) in alcohol (10 ml) cooled to 5°C was added gradually with stirring to the obtained
suspension at room temperature. The reaction mixture was stirred for 1 h at 20°C. The precipitated solid was
1
84

filtered off, washed three times on the filter with water, and recrystallized from alcohol–DMF. Arylhydrazone 2a
-
1
(
0.8 g, 42.6%) was obtained; mp 225-226°C. IR spectrum, ν, cm : 2220 (CN), 1720 (CO), 1610 (N–N=C). UV
1
spectrum, λmax, nm (log ε): 205.6 (1.92), 247.6 (1.94), 380.8 (1.91). H NMR spectrum (DMSO-d ), δ, ppm: 2.35
6
(
3H, s, CH ); 7.18-7.46 (5H, m, C H ); 7.72-7.85 (4H, m, C H ); 13.58 (1H, s, NH). Found, %: C 67.14; H 4.21;
3 6 5 6 4
N 22.71. C H N O. Calculated, %: C 67.31; H 4.32; N 23.09.
1
7
13
5
The other arylhydrazones 2 were obtained analogously from the appropriate salts 4 and 1-aryl-3-
methylpyrazol-5-ones 3.
-(2-Cyanophenyl)hydrazone of 3-Methyl-1-(p-sulfophenyl)pyrazole-4,5-dione (2b). Yield 63%;
4
-
1
mp 331°C (water). IR spectrum, ν, cm : 2230 (CN), 1665 (CO), 1605 (N–N=C), 1345, 1120 (SO OH).
UV spectrum, λmax, nm (log ε): 205.2 (1.84), 250.0 (1.55), 385.6 (1.62). H NMR (DMSO-d ), δ, ppm: 2.35 (3H,
2
1
6
s, CH ); 7.30-7.53 (4H, C H -o); 7.72-7.92 (4H, C H -p); 8.22 (1H, s, SO H); 13.60 (1H, s, NH). Found, %:
3
6
4
6
4
3
C 53.12; H 3.42; N 18.01. C H N O S. Calculated, %: C 53.25; H 3.42; N 18.36.
1
7
13
5
4
4
-(4-Bromo-2-cyanophenyl)hydrazone of 3-Methyl-1-phenylpyrazole-4,5-dione (2c). Yield 51%; mp
-
1
2
32°C (alcohol–DMF). IR spectrum, ν, cm : 2224 (CN), 1720 (CO), 1625 (N–N=C). UV spectrum, λmax, nm
(
log ε): 206 (1.78), 246.8 (1.72), 385.6 (1.73). Found, %: C 53.12; H 3.16; N 18.32. C H BrN O. Calculated,
1
7
12
5
%: C 53.42; H 3.16; N 18.32.
4
-(2-Cyanophenyl)hydrazone of 3-Methyl-1-(p-tolyl)pyrazole-4,5-dione (2d). Yield 86%; mp 234°C
-
1
(
(
alcohol–DMF). IR spectrum, ν, cm : 2230 (CN), 1670 (CO), 1605 (N–N=C). UV spectrum, λ (log ε): 205.6
1.84), 246.8 (1.76), 381.2 (1.69). H NMR spectrum (DMSO-d ), δ, ppm: 2.33 and 2.34 (3H, s, CH and 3H, s,
max
1
6
3
CH ); 7.20-7.88 (8H, m, C H -p and C H -o); 13.64 (1H, s, NH). Found, %: C 69.38; H 4.48; N 22.34.
3
6
4
6
4
C H N O. Calculated, %: C 68.12; H 4.78; N 22.07.
1
8
15
5
4
-(4-Bromo-2-cyanophenyl)hydrazone of 3-Methyl-1-(p-sulfophenyl)pyrazole-4,5-dione (2e).
-
1
Yield 74%; mp 341°C (alcohol–water). IR spectrum, ν, cm : 2240 (CN), 1665 (CO), 1615 (N–N=C), 1335,
115 (SO OH). UV spectrum, λmax, nm (log ε): 206.8 (1.67), 250.4 (1.28), 394.0 (1.39). Found, %: C 44.37;
1
2
H 2.42; N 15.48. C H BrN O S. Calculated, %: C 44.16; H 2.61; N 15.15.
1
7
12
5
4
4
-(2-Cyano-4-nitrophenyl)hydrazone of 3-Methyl-1-phenylpyrazole-4,5-dione (2f). Yield 69%;
-
1
mp 275°C (alcohol–DMF). IR spectrum, ν, cm : 2228 (CN), 1735 (CO), 1615 (N–N=C), 1540, 1365 (NO ). UV
2
spectrum, λmax, nm (log ε): 204.4 (1.59), 246.4 (1.58), 393.6 (1.59). Found, %: C 59.03; H 3.15; N 23.78.
C H N O . Calculated, %: C 58.62; H 3.47; N 24.13.
1
7
12
6
3
4
-(2-Cyano-4-nitrophenyl)hydrazone of 3-Methyl-1-(p-tolyl)pyrazole-4,5-dione (2g). Yield 83%; mp
-
1
2
80°C (alcohol–DMF). IR spectrum, ν, cm : 2234 (CN), 1705 (CO), 1620 (N–N=C), 1515(NO ), 1340.
2
UV spectrum, λmax, nm (log ε): 206.0 (1.73), 244.4 (1.68), 394.2 (1.28). Found, %: C 59.54; H 4.25; N 23.47.
C H N O . Calculated, %: C 59.66; H 3.89; N 23.19.
1
8
14
6
3
4
-(2-Cyano-4-nitrophenyl)hydrazone of 3-Methyl-1-(p-sulfophenyl)pyrazole-4,5-dione (2h).
-
1
Yield 72%; mp 369°C (alcohol–water). IR spectrum, ν, cm : 2235 (CN), 1660 (CO), 1625 (N–N=C),
520(NO ), 1370, 1330, 1125 (SO OH). UV spectrum, λmax, nm (log ε): 205.2 (1.76), 301.2 (1.41), 400.0 (0.91).
1
2
2
Found, %: C 47.28; H 2.98; N 19.09. C H N O S. Calculated, %: C 47.66; H 2.82; N 19.61.
1
7
12
6
6
4
-(4-Bromo-2-cyanophenyl)hydrazone of 3-Methyl-1-(p-tolyl)pyrazole-4,5-dione (2i). Yield 94%;
-
1
mp 243°C (alcohol–DMF). IR spectrum, ν, cm : 2232 (CN), 1660 (CO), 1620 (N–N=C). UV spectrum,
λmax (log ε): 208.8 (1.84), 247.2 (1.78), 385.2 (1.64). Found, %: C 54.18; H 3.42; N 17.18. C H N O.
18
14
5
Calculated, %: C 54.46; H 3.56; N 17.67.
The work was carried out with the financial support of the Russian Fund for Fundamental Investigations
project No. 00-15-97359 and No. 99-07-90133).
(
1
85

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