Reaction of allyl phenylcarbamate with benzaldehyde phenylhydrazones in the presence of N-chlorobenzenesulfonamide sodium salt

Article abstract of DOI:10.1007/s11178-005-0047-8

Phenylhydrazones derived from 4-bromo-, 4-methoxy-, and 3-nitrobenzaldehydes react with allyl phenylcarbamate in the presence of N-chlorobenzenesulfonamide sodium salt to give the corresponding 3-aryl-1-phenyl-5-(phenylcarbamoyloxymethyl)-4,5-dihydro-1H-p

Full text of DOI:10.1007/s11178-005-0047-8

Russian Journal of Organic Chemistry, Vol. 40, No. 10, 2004, pp. 1490–1492. Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004,
pp. 1539–1541.
Original Russian Text Copyright © 2004 by Velikorodov.
Reaction of Allyl Phenylcarbamate
with Benzaldehyde Phenylhydrazones in the Presence
of N-Chlorobenzenesulfonamide Sodium Salt
A. V. Velikorodov
Astrakhan State University, ul. Tatishcheva 20a, Astrakhan, 414056 Russia
e-mail: avelikorodov@mail.ru
Received May 20, 2003
Abstract—Phenylhydrazones derived from 4-bromo-, 4-methoxy-, and 3-nitrobenzaldehydes react with allyl
phenylcarbamate in the presence of N-chlorobenzenesulfonamide sodium salt to give the corresponding 3-aryl-
1-phenyl-5-(phenylcarbamoyloxymethyl)-4,5-dihydro-1H-pyrazoles whose structure was confirmed by the IR
and 1H and 13C NMR spectra.
lead tetraacetate as a reagent for generation of nitril-
imines, for it prevents possible formation of diacyl-
hydrazines [5]. The synthetic potential and specific
features of 1,3-dipolar cycloaddition of alkenyl carba-
mates to nitrilimines generated in situ by the action of
N-chlorobenzenesulfonamide sodium salt on benzalde-
hyde phenylhydrazones remain almost unstudied.
We previously studied reactions of allyl and
2-propynyl phenylcarbamates with benzaldehyde
oximes in the presence of N-chlorobenzenesulfon-
amide sodium salt; these reactions occurred with high
regioselectivity and resulted in formation of 3,5-disub-
stituted 4,5-dihydroisoxazoles and isoxazoles [1–3]. In
continuation of these studies, the present communica-
tion reports on reactions of phenylhydrazones derived
from substituted benzaldehydes with allyl phenylcar-
bamate in the presence of N-chlorobenzenesulfon-
amide sodium salt. It should be noted that generation
of nitrilimines from aromatic and aliphatic aldehyde
phenylhydrazones by the action of N-chloro-p-toluene-
sulfonamide sodium salt and addition of these species
to acrylonitrile, styrene, and ethyl acrylate with forma-
tion of the corresponding dihydropyrazoles were
reported for the first time in [4]. N-Chlorobenzene-
sulfonamide sodium salt is more advantageous than
Reactions of allyl phenylcarbamate (I) with benz-
aldehyde, p-bromobenzaldehyde, m-nitrobenzalde-
hyde, and p-methoxybenzaldehyde phenylhydrazones
IIa–IId in the presence of N-chlorobenzenesulfon-
amide sodium salt were carried out by heating a mix-
ture of the reactants in boiling ethanol over a period of
3 h. After treatment of the mixture with diethyl ether
[1], the precipitate was filtered off, and the product
was isolated by column chromatography and was
additionally purified by recrystallization from diethyl
ether–petroleum ether (1:2).
Scheme 1.
3'''
4'''
2'''
1'''
5'''
O
6'''
H
H
PhSO2NCl Na
EtOH, reflux
HN
N
O
N
N
Ph
O
R
+
4
5
O
2''
2'
1N
3
3''
4''
3'
1'
6'
R
1''
6''
N
4'
2
5''
5'
I
IIa–IId
IIIb–IIId
II, III, R = H (a), 4-Br (b), 3-O2N (c), 4-MeO (d).
1070-4280/04/4010-1490 © 2004 MAIK “Nauka/Interperiodica”

REACTION OF ALLYL PHENYLCARBAMATE
1491
1
Analysis of the products by IR and H and 13C
NMR spectroscopy showed that the cycloaddition of
nitrilimines, as well as of unsubstituted and substituted
benzonitrile oxides, occurs with high regioselectivity,
leading to formation of the corresponding 3-aryl-1-
phenyl-5-(phenylcarbamoyloxymethyl)-4,5-dihydro-
pyrazoles IIIb–IIId in 32–54% yield. The spectral par-
ameters of compounds IIIb–IIId are consistent with
those reported for structurally related compounds [4].
from protons. The purity of the products was checked
by TLC on Silufol UV-254 plates.
3-(4-Bromphenyl)-1-phenyl-5-(phenylcarba-
moyloxymethyl)-4,5-dihydropyrazole (IIIb). A mix-
ture of 0.70 g (3.96 mmol) of allyl phenylcarbamate
(I), 1.10 g (4.0 mmol) of phenylhydrazone IIb, and
1.12 g (4.18 mmol) of N-chlorobenzenesulfonamide
sodium salt trihydrate in 16 ml of anhydrous ethanol
was heated for 3 h under reflux. The precipitate was
filtered off, the solvent was distilled off from the
filtrate, and the residue was treated with methylene
chloride (2×25 ml). The extract was washed with
water (2×25 ml) and 1 N aqueous sodium hydroxide
(2×50 ml) and dried over sodium sulfate, the solvent
was removed, the residue was dissolved in 15 ml of
diethyl ether, the solution was cooled, and the crystals
were filtered off. The ether solution was applied to
a column charged with silica gel L 100/160 µm, and
the column was eluted with diethyl ether to isolate
0.89 g (50%) of compound IIIb. Light yellow crystals,
mp 125–126°C (from diethyl ether–petroleum ether,
1:2). IR spectrum, ν, cm–1: 3340 (NH); 1725 (C=O);
High-melting crystalline products, which were in-
soluble in diethyl ether, were purified by reprecipita-
tion from DMF with diethyl ether. In the reaction with
benzaldehyde phenylhydrazone IIa, apart from unre-
acted carbamate I, the only isolated product was
a high-melting substance (yield 62%). On the basis of
the IR spectrum and elemental composition, this prod-
uct was assigned the structure of 1,3,4,6-tetraphenyl-
1,2,4,5-tetraaza-2,5-hexadiene (IV). Presumably, this
compound is formed by dimerization of intermediate
C,N-diphenylnitrilimine.
Ph
1
PhCH
N
N
C
N
NHPh
1610, 1585, 1530 (C=Carom). H NMR spectrum, δ,
Ph
ppm (J, Hz): 8.54 br.s (1H, NH), 8.02 d (2H, Harom
J = 8.3), 7.94 d (2H, Harom, J = 8.3), 7.40 d (2H, Harom
,
,
IV
J = 8.8), 7.21 m (2H, Harom), 6.97 m (6H, Harom),
4.28 m (2H, OCH2), 3.93 m (1H, 5-H), 3.41 d.d (1H,
4-H, J = 8.4, 12.2), 3.20 d.d (1H, 4-H, J = 8.0, 12.2).
13C NMR spectrum, δC, ppm: 38.52 (C4), 56.80
(OCH2), 58.43 (C5), 112.04 (C2'', C6''), 119.10 (C4''),
119.19 (C2''', C6'''), 122.51 (C3''', C5'''), 123.42 (C4'),
123.55 (C4'''), 127.52 (C2', C6), 127.76 (C3'', C5''), 129.71
(C1'), 130.32 (C3', C5'), 134.04 (C1'''), 145.72 (C1''),
148.38 (C=N), 154.31 (C=O). Found, %: C 61.09;
H 4.14; N 9.27. C23H20BrN3O2. Calculated, %: C 61.33;
H 4.44; N 9.33.
In the reactions with the other hydrazones, the
yields of the high-melting products were considerably
lower. Relatively low yields of dihydropyrazoles IIIb–
IIId, as well as formation of nitrilimine dimerization
products, may be rationalized in terms of higher reac-
tivity of nitrilimines as compared to benzonitrile
oxides and low reactivity of allyl phenylcarbamate as
dipolarophile. Nevertheless, despite the above draw-
backs, the reaction of benzaldehyde phenylhydrazones
with allyl phenylcarbamate in the presence of
N-chlorobenzenesulfonamide sodium salt provides
a convenient method for the synthesis of 1,3,5-trisub-
stituted dihydropyrazoles.
3-(m-Nitrophenyl)-1-phenyl-5-(phenylcarba-
moyloxymethyl)-4,5-dihydropyrazole (IIIc) was syn-
thesized in a similar way from 0.35 g (1.98 mmol) of
allyl phenylcarbamate (I), 0.48 g (1.99 mmol) of
m-nitrobenzaldehyde phenylhydrazone (IIc), and
0.56 g (2.09 mmol) of N-chlorobenzenesulfonamide
sodium salt trihydrate. Yield 0.40 g (54%). Light
yellow crystals, mp 105–107°C (from diethyl ether–
petroleum ether, 1:2). IR spectrum, ν, cm–1: 3340
(NH); 1720 (C=O); 1610, 1585, 1535 (C=Carom); 1530,
EXPERIMENTAL
The IR spectra were recorded in the range from
4000 to 400 cm–1 on an IKS-29 spectrometer from
samples dispersed in mineral oil. The 1H NMR spectra
were recorded on a Bruker AC-200 instrument at
200.13 MHz) from solutions in acetone-d6 using tetra-
1
1355 (NO2). H NMR spectrum, δ, ppm (J, Hz):
13
methylsilane as internal reference. The C NMR spe-
8.66 br.s (1H, NH), 8.20 d (1H, Harom, J = 7.7), 8.02 s
(1H, Harom), 7.94 t (1H, Harom, J = 7.7), 7.36 d (2H,
Harom, J = 7), 7.21 t (3H, Harom, J = 7.8), 6.94 m (6H,
ctra were measured in acetone-d6 on a Bruker WM-400
spectrometer (100 MHz) with complete decoupling
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 40 No. 10 2004

VELIKORODOV
1492
H
arom), 4.26 m (2H, OCH2), 3.94 m (1H, 5-H), 3.50 d.d
δC, ppm: 38.48 (C4), 55.10 (OMe), 56.85 (OCH2),
58.37 (C5), 112.04 (C2'', C6''), 112.90 (C3', C5'), 119.10
(C4''), 119.17 (C2''', C6'''), 122.54 (C3''', C5'''), 123.54
(C4'''), 124.60 (C1' ), 127.87 (C2', C6'), 127.92 (C3'', C5''),
134.01 (C1'''), 145.34 (C1''), 148.36 (C=N), 154.43
(C=O), 159.21 (C4'). Found, %: C 71.59; H 6.02;
N 10.30. C24H23N3O3. Calculated, %: C 71.82; H 5.74;
N 10.47.
1,3,4,6-Tetraphenyl-1,2,4,5-tetraaza-2,5-hexadi-
ene (IV) was isolated as a crystalline substance. Yield
62%, mp 202°C; published data [5]: mp 200–202°C.
IR spectrum, ν, cm–1: 3330 (NH), 1620–1535 (C=Carom).
Found, %: C 79.78; H 5.48; N 14.44. C26H22N4. Cal-
culated, %: C 80.00; H 5.54; N 14.36.
(1H, 4-H, J = 7.8, 10.2), 3.44 d.d (1H, 4-H, J = 8.3,
10.2). C NMR spectrum, δC, ppm: 38.52 (C4), 55.62
13
(OCH2), 58.39 (C5), 112.03 (C2'', C6''), 119.12 (C4''),
119.18 (C2''', C6'''), 122.02 (C2'), 122.54 (C3''', C5'''),
123.51 (C4'''), 125.08 (C4'), 127.67 (C3'', C5''), 129.21
(C5'), 132.76 (C1'), 133.92 (C6'), 134.57 (C1'''), 145.95
(C1''), 146.88 (C3'), 148.42 (C=N), 153.87 (C=O).
Found, %: C 66.10; H 4.78; N 13.19. C23H20N4O4.
Calculated, %: C 66.35; H 4.81; N 13.46.
3-(4-Methoxyphenyl)-1-phenyl-5-(phenylcarba-
moyloxymethyl)-4,5-dihydropyrazole (IIId) was
synthesized in a similar way from 0.35 g (1.98 mmol)
of allyl phenylcarbamate (I), 0.45 g (1.99 mmol) of
p-methoxybenzaldehyde phenylhydrazone (IId), and
0.56 g (2.09 mmol) of N-chlorobenzenesulfonamide
sodium salt trihydrate. Yield 0.25 g (32%). Light
yellow crystals, mp 95–97°C (from diethyl ether–
petroleum ether, 1:2). IR spectrum, ν, cm–1: 3340
(NH); 1725 (C=O); 1620, 1575, 1535 (C=Carom).
1H NMR spectrum, δ, ppm (J, Hz): 8.50 br.s (1H, NH),
7.87 d (2H, Harom, J = 8.4), 7.36 d (2H, Harom, J = 8.8),
7.20 m (3H, Harom), 7.07 m (5H, Harom), 6.67 d (2H,
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3.62 s (3H, OMe), 3.53 d.d (1H, 4-H, J = 8.5, 10.2),
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13
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