Nitration of some 3-(2-furyl)-2-propenones with dinitrogen tetraoxide

Article abstract of DOI:10.1007/s11178-005-0181-3

Nitration of 3-(2-furyl)-2-propenones with dinitrogen tetraoxide leads to the corresponding 3-(4-nitro-2-furyl)-2-propenones. If the furyl group contains a substituent in position 5, the nitration occurs at the side chain to afford 3-(5-R-2-furyl)-2-nitro

Full text of DOI:10.1007/s11178-005-0181-3

Russian Journal of Organic Chemistry, Vol. 41, No. 3, 2005, pp. 423–428. Translated from Zhurnal Organicheskoi Khimii, Vol. 41, No. 3, 2005,
pp. 431–436.
Original Russian Text Copyright © 2005 by Sitkin, Klimenko.
Nitration of Some 3-(2-Furyl)-2-propenones
with Dinitrogen Tetraoxide
A. I. Sitkin and V. I. Klimenko
Kazan State Technological University, ul. K. Marksa 68, Kazan, 420015 Tatarstan, Russia
Received July 8, 2003
Abstract—Nitration of 3-(2-furyl)-2-propenones with dinitrogen tetraoxide leads to the corresponding
3-(4-nitro-2-furyl)-2-propenones. If the furyl group contains a substituent in position 5, the nitration occurs at
the side chain to afford 3-(5-R-2-furyl)-2-nitro-2-propenones.
3-(5-Nitro-2-furyl)-2-propenones are known to
exhibit strong bactericidal and bacteriostatic activity
[1]. These compounds are usually prepared by cro-
tonization of 5-nitrofuraldehyde with appropriate
ketones [1] or by reaction of 3-(2-furyl)-2-propenones
with nitric acid in acetic anhydride [2]. The goal of
the present work was to synthesize new isomeric nitro
compounds of the above series by reaction of equi-
molar amounts of liquid dinitrogen tetraoxide with
3-(2-furyl)-2-propenones Ia–Ij in diethyl ether at
reduced temperature.
ketone IIIf as a result of replacement of the halogen
atom in the furan ring by nitro group.
According to published data [3], nitration of un-
saturated compounds with dinitrogen tetraoxide under
analogous conditions (equimolar amounts of the reac-
tants, diethyl ether, cooling) follows a radical mechan-
ism and occurs at the most spatially accessible carbon
atom. Therefore, the observed reaction pathways
(a and b in Scheme 1) indicate that the most spatially
accessible reaction centers in furylpropenones Ia–Ij
are C4 in the furan ring and the α-carbon atom (with
respect to the carbonyl group). The side-chain carbon
atom in molecules Ia–Ie is partially shielded by bulky
acyl groups (COC6H4R), and the nitration follows
mainly pathway a provided that no substituent is pres-
ent in position 5 of the furan ring. Otherwise (com-
pounds If–Ij), position 4 in the heteroring becomes
less accessible, and the reaction occurs according to
pathway b.
We have found that the nitration products of furyl-
propenones Ia–Ie having no substituent in the furan
ring are the corresponding 3-(4-nitro-2-furyl)-2-pro-
penones IIa–IIe (Scheme 1). However, treatment with
dinitrogen tetraoxide of compounds If–Ih containing
a substituent in position 5 of the heteroring leads to
formation of products with a nitro group in the side
chain, substituted 3-(5-R-2-furyl)-2-nitro-2-propenones
IIIf–IIIh. The nitration of 5-bromo- and 5-iodofuryl
derivatives Ii and Ij also affords unsaturated dinitro-
It was reasonable to presume that the absence of
bulky acyl groups and substituents in the furan ring
Scheme 1.
O2N
R
R'
R'
a
b
O
O
O
R'
N2O4
IIa–IIe, IIk, IIl
R
O
–HNO2
O
O2N
Ia–Il
R
O
IIIf–IIIh
I, II, R = H, R' = Ph (a), 4-ClC6H4 (b), 4-BrC6H4 (c), 4-MeC6H4 (d), 4-MeOC6H4 (e), OH (k), H (l);
I, III, R = NO2, R' = Ph (f), Me (g), R = R' = Me (h); I, R' = Ph, R = Br (i), I (j).
1070-4280/05/4103-0423 © 2005 Pleiades Publishing, Inc.

SITKIN, KLIMENKO
424
Scheme 2.
O2N
O2N
N2O4
H
H
[O]
OH
CHNO2
–HNO2
–CO2
O
O
O
O
O
O
O
Il
A
IV
should favor nitration of compounds Ik and Il with
dinitrogen tetraoxide at both reaction centers. In fact,
by reacting 3-(2-furyl)acrylic acid (Ik) and 3-(2-furyl)-
acrylaldehyde (Il) with N2O4 we isolated in each case
two nitro derivatives: 4-nitrofuryl IIk and IIl (pathway
a) and 1-(2-furyl)-2-nitroethylene (IV); the latter prod-
uct was identified by comparison with an authentic
sample [4]. The formation of nitroalkene IV from
furylacrylic acid Ik may be explained by easy decar-
boxylation of intermediate 3-(2-furyl)-2-nitroacrylic
acid (A) which is formed along pathway b. In the
nitration of aldehyde Il, the primary nitration product,
3-(2-furyl)-2-nitro-2-propenal (pathway b), is likely to
be readily oxidized to acid A whose decarboxylation
yields nitroalkene IV (Scheme 2).
(5'-H) and a quartet from 4'-H (J3,4 ≈ 3.5, J4,5 ≈ 1.8 Hz).
All protons in the spectra of 4-nitrofuryl derivatives
IIa–IIe and IIk resonate in a weaker field due to
deshielding by the nitro group, the largest downfield
shifts being observed for the 3'-H and 5'-H signals
(∆δ 0.51–0.74 and 1.01–1.13 ppm, respectively). The
spectra lack quartet signal corresponding to 4'-H in
the initial compounds, and the 3'-H and 5'-H signals
appear as singlets rather than doublets. The side-chain
olefinic protons, as in the spectra of the initial com-
pounds, give rise to an AA' system with the same
coupling constant (3Jtrans = 16 Hz). The aldehyde
proton signal and that from 3-H in the spectra of Il and
IIl are doublets, and the 2-H signal is a quartet. ortho-
and meta-Aromatic protons in IIb–IIe give doublets
with coupling constants of 8.0–8.5 Hz, and aromatic
protons in IIa and IIIf appear as multiplets. Signals
from the methyl group protons were also present in the
spectra of ketones IId, IIe, IIIg, and IIIh.
The IR spectra of initial compounds I indicate the
existence of conjugation between the double bond
π-electron systems in their molecules: νC=C 1648–1605,
νC=O 1680–1655 cm–1. In the IR spectra of nitro
derivatives II and III, the carbonyl absorption band is
displaced by 5–20 cm–1 toward higher frequencies; this
means that the conjugation between the carbonyl group
and double C=C bond weakens. The C=C absorption
frequency also increases (by 3–12 cm–1). In addition,
the IR spectra of II and III contain strong absorption
bands due to asymmetric and symmetric vibrations of
the conjugated nitro group in the regions 1545–1525
and 1375–1350 cm–1, respectively. The furan ring
gives rise to characteristic absorption bands at 3155–
3120, 1035–1015, and 890–868 cm–1. The bands in
the regions 1230–1070 and 850–812 cm–1 correspond
to in-plane and out-of-plane bending vibrations of the
aromatic C–H bonds. Stretching vibrations of the latter
appear at 3072–3010 cm–1. Compounds containing
methoxy (2845, 1255 cm–1) or methyl groups (2870–
2856, 1482–1460 cm–1) and C–Cl (740–700 cm–1) or
C–Br bonds (650, 560 cm–1) showed in the IR spectra
the corresponding absorption bands.
The 1H NMR spectra of III lack signal correspond-
ing to 2-H in initial ketones If–Ij [δ, ppm: 6.80–7.58 d
3
(2-H), 7.12–7.92 d (3-H), J2,3 ≈ 16 Hz], while signals
from the other protons are located in a weaker field.
The 3-H proton in III is the most deshielded (δ 0.45–
0.49 ppm); it appears as a singlet, for there is no proton
in the neighboring position (C2). The furan ring pro-
tons (3'-H and 4'-H) give rise to two doublets.
In going from solutions of compounds II and III
in acetone-d6 to solutions in DMSO-d6, signals from
all protons in their molecules shift downfield. The
largest shift for compounds II was observed for 5'-H
(∆δ 0.52–0.62 ppm); the other signals were displaced
downfield to a lesser extent (∆δ3-H 0.19–0.30,
∆δ2-H 0.17–0.30, ∆δ1-H 0.13–0.40, ∆δo-H 0.17–0.29,
∆δm-H 0.22–0.26 ppm). Compounds III were also
characterized by large and positive ∆δ values (0.25–
0.47 ppm) for all protons. It should be noted that the
difference in the chemical shifts of protons in II and
III, on the one hand, and initial compounds, on the
other, are larger in DMSO-d6 than in acetone-d6. For
example, ∆δ values in DMSO for 5'-H in IIa, IIb, and
IId, as compared to Ia, Ib, and Id (δ 8.05–8.15 ppm,
d), range from 1.20 to 1.41 ppm, and for 3-H in III,
from 0.57 to 0.67 ppm (If–Ih, δ3-H 7.47–8.09 ppm,
DMSO-d6).
1
The H NMR spectra of initial compounds Ia–Ie
and Ik in acetone-d6 are characterized by the presence
of two doublets from the trans-ethylene protons (2-H
3
and 3-H, AA' system) with a coupling constant J of
16 Hz and signals from protons in the furan ring:
doublets at δ 6.90–7.16 (3'-H) and 7.70–7.82 ppm
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 3 2005

NITRATION OF SOME 3-(2-FURYL)-2-PROPENONES
Dipole moments of compounds Ia, Ib, Il, IIa, IIb, and IIl
425
According to [5], ketone Ia exists mainly as syn-
trans-s-cis conformer, while aldehyde Il is charac-
terized by syn-trans-s-trans conformation. We have
determined the configuration of compounds Ia, Ib, Il,
IIa, IIb, and IIl. The coupling constant for the olefinic
µ
calc, D
anti isomer
Comp. no.
µ
exp, D
syn isomer
3.59
3.82
3.41
3.07
4.58
2.54
3.55
1.75
2.97
1.04
4.09
1.80
2.73
4.77
2.59
3.22
3.26
5.14
Ia
1
IIa
Ib
IIb
Il
protons in the H NMR spectra is equal to ~16 Hz,
indicating trans-configuration of the double bond. The
greater intensity of the νC=C band as compared to νC=O
(νC=O/νC=C = 0.3–0.5) in the IR spectra of ketones Ia,
Ib, IIa, and IIb suggests that the conjugated carbonyl
group and ethylene moiety are arranged s-cis [5]. The
intensity ratio of the C=O and C=C absorption bands
in the IR spectra of aldehydes Il and IIl is equal to 2.5,
which is typical of transoid orientation of the corre-
sponding groups [6].
IIl
dipole moments of ketones IIa and IIb and aldehyde
IIl occupy an intermediate place between the values
calculated for their syn and anti conformers; therefore,
these compounds give rise to equilibrium mixtures of
the syn and anti conformers. Using the formula µ =
The fractions of the syn and anti isomers of trans-s-
cis-ketones Ia, Ib, IIa, and IIb and trans-s-trans-
aldehydes Il and IIl were estimated by comparing the
experimental dipole moments with those calculated
by the vector additivity scheme for the corresponding
conformations (see table). The calculations were per-
formed using the formula µ = (mx2 + my2)1/2, where mx
and my are, respectively, the sums of the projections
of the bond dipole moments on the x and y axes. The
coordinate system was set in such a way that the x axis
passed through positions 2 and 5 of the furan ring, and
the y axis, through position 3. The required parameters
of 2-substituted furan ring and dipole moments of
particular groups and bonds in molecules Ia, Ib, Il,
IIa, IIb, and IIl were taken from [5]. The dipole
moment of the nitro group in position 4 of the furan
ring was assumed to be 4.01 D (i.e., as in nitrobenzene
[7]), and the moment of chlorine in aromatic ring was
taken equal to 1.59 D [7].
2
2
(1 – x)µ1 + xµ2 , we obtained the following fractions
of the syn conformer: IIa, 0.41; IIb, 0.10; IIl, 0.86.
The formation of an equilibrium mixture of syn and
anti conformers of the above compounds may be
rationalized in terms of electron-acceptor effect of the
nitro group, which weakens π-electron density transfer
in the conjugated system furan ring–ethylene frag-
ment–carbonyl group from the former to the latter. As
a result, rotation of the furan ring about the C3–C2'
bond becomes possible.
The experimental dipole moments of nitro ketones
IIIf–IIIh in which the nitro group is located at the
side-chain double bond are 5.04, 4.96, and 5.79 D,
respectively. These values considerably exceed those
found for initial compounds If–Ih having a planar
structure (3.48, 3.72, and 4.34 D, respectively). Pre-
sumably, the nitro group in molecules III is forced out
from the plane of the rest of the molecule, thus ruling
out or strongly reducing its conjugation with the furan
ring and carbonyl group.
As follows from the data collected in table, both
s-cis-propenones Ia and Ib and s-trans-acrolein Il in
solution exist mainly as syn conformers. However,
introduction of a nitro group into the furan ring shifts
the conformational equilibrium. The experimental
Carbonyl compounds II and III can readily be con-
verted into the corresponding 2,4-dinitrophenylhydra-
zones V. The IR spectra of the latter lack absorption
R
H
H
O
C6H4R'
C6H4R'
R
O
O
H
O
H
syn Isomer
Ia, Ib, IIa, IIb
anti Isomer
R
H
H
O
O
O
R
O
H
H
H
H
anti Isomer
Il, IIl
syn Isomer
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 3 2005

SITKIN, KLIMENKO
426
Scheme 3.
O2N
N
N
NaN3
HCl
R'
R
N
R
N
O
O
–HNO2
–NaCl
R
NNa
NH
O
O
R'CO
R'CO
VIf–VIh
IIIf–IIIh
due to carbonyl stretching vibrations, but bands be-
longing to vibrations of the C=N (1615 cm–1) and N–H
bonds (3450, 3400, and 1315 cm–1) are present. Treat-
ment of ketones III with sodium azide in a dipolar
50 ml of diethyl ether was cooled to –15°C, 10 mmol
of dinitrogen tetraoxide was added, and the mixture
was stirred for 2 h at that temperature and poured onto
100 g of finely crushed ice. After 3 h, the organic
phase was separated, and the solvent was evaporated.
The residue was washed in succession with water and
alcohol, and recrystallized from appropriate solvent.
We thus isolated nitro ketones IIa–IIe and IIIh.
Following the same procedure, in the reaction of
aldehyde Il with N2O4, apart from 4-nitrofuryl deriva-
tive IIl, we isolated by fractional crystalization from
carbon tetrachloride 14% of furylnitroethylene IV with
mp 74°C [4]. Compound IV was also isolated in 18%
yield (mp 74–75°C, from CCl4) in addition to nitro
acid IIk in the nitration of 3-(2-furyl)acrylic acid (Ik).
Dinitro ketone IIIf was synthesized from compound If,
Ii, or Ij and dinitrogen tetraoxide at a reactant molar
ratio of 1:4; the reaction mixture was stirred for 3 h at
0°C); yield 47, 32, and 33%, respectively. Likewise,
dinitropropenone IIIg was synthesized from com-
pound Ig using 2 equiv of N2O4 (temperature 17°C).
aprotic (DMF) or protic solvent (EtOH) afforded the
corresponding 5-acyl-4-(2-furyl)-1H-1,2,3-triazoles VI.
The reaction is likely to occur via [3+2]-cycloaddition
of azide ion at the double bond and elimination of
nitrous acid molecule (Scheme 3). Compounds VI
showed in the IR spectra absorption bands at 1690–
1650 (C=O), 3200–3100 (NH), 1530–1520 and 1360–
1350 (NO2), 1020–990 (triazole ring), 1500, 1030, 890,
775 (furan), 1380 (Me), and 1600, 1248–1240, 1186–
1155 cm–1 (arom.). Unlike initial compounds III, the
1H NMR spectra of VI contained no signals assignable
to olefinic proton. 4-Nitrofuryl derivatives II failed
to react with sodium azide; presumably, the olefinic
double bond in these compounds is insufficiently elec-
trophilic.
EXPERIMENTAL
3-(4-Nitro-2-furyl)-1-phenyl-2-propenone (IIa).
Yield 15%, mp 157–158°C (from EtOH). IR spectrum,
ν, cm–1: 1620 (C=C); 1680 (C=O); 1540, 1368 (NO2).
1H NMR spectrum, δ, ppm: in acetone-d6: 7.46 d (1H,
2-H, J = 15.8 Hz), 7.56 s (1H, 1-H), 7.65–8.12 m (5H,
The IR spectra were recorded on a UR-20 spectro-
photometer from samples dispersed in mineral oil. The
intensity ratio of the νC=O and νC=C bands was deter-
mined by cutting and weighing the corresponding
1
peaks. The H NMR spectra were recorded from solu-
Harom), 7.82 d (1H, 3-H, J = 15.8 Hz), 8.83 s (1H,
tions in acetone-d6 on a Varian CFT-20 spectrometer
(80 MHz) and in DMSO-d6 on a Tesla BS 487C
spectrometer (80 MHz). The chemical shifts were
measured relative to tetramethylsilane. The dipole
moments were determined by the Debye technique
from dilute solutions [7] in dioxane at 25±0.1°C using
an ON-302 precision dielcometer; the solvent was
purified by the procedure described in [8]. The com-
pounds under study were recrystallized until constant
melting point and were dried under reduced pressure.
The purity of the products was checked by TLC on
Silufol UV-254 plates using benzene as eluent; spots
were visualized under UV light. Initial compounds Ia–
Il were synthesized and purified by the procedures
reported in [9].
5'-H); in DMSO-d6: 7.73 d (1H, 2-H, J = 16.0 Hz),
7.87–8.29 m (5H, Harom), 7.95 s (1H, 1-H), 8.01 d
(1H, 3-H, J = 16.0 Hz), 9.35 s (1H, 5'-H). Found, %:
C 64.46; H 3.90; N 5.82. C13H9NO4. Calculated, %:
C 64.14; H 3.70; N 5.76.
1-(4-Chlorophenyl)-3-(4-nitro-2-furyl)-2-pro-
penone (IIb). Yield 14%, mp 190–191°C (from
EtOH). IR spectrum, ν, cm–1: 1620 (C=C); 1670
(C=O); 1530, 1370 (NO2). 1H NMR spectrum, δ, ppm:
in acetone-d6: 7.54 d (1H, 2-H, J = 15.8 Hz), 7.66 d
(2H, m-H, J = 8.5 Hz), 7.69 s (1H, 1-H), 7.79 d (1H,
3-H, J = 15.8 Hz), 8.12 d (2H, o-H, J = 8.5 Hz), 8.84 s
(1H, 5'-H); in DMSO-d6: 7.80 d (1H, 2-H, J =
15.9 Hz), 7.92 d (2H, m-H, J = 8.0 Hz), 8.03 s (1H,
1-H), 8.09 d (1H, 3-H, J = 15.9 Hz), 8.41 d (2H, o-H,
J = 8.0 Hz), 9.46 s (1H, 5'-H). Found, %: C 56.08;
Nitro compounds II and III (general procedure).
A solution of 10 mmol of compound Ia–Ie or Ih in
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 3 2005

NITRATION OF SOME 3-(2-FURYL)-2-PROPENONES
427
H 2.92; Cl 13.03; N 5.16. C13H8ClNO4. Calculated, %:
C 56.23; H 2.90; Cl 12.78; N 5.04.
2-Nitro-3-(5-nitro-2-furyl)-1-phenyl-2-pro-
penone (IIIf). Yield 47%, mp 140–141°C (from
AcOH). IR spectrum, ν, cm–1: 1655 (C=C); 1680
(C=O); 1540, 1350 (NO2). 1H NMR spectrum, δ, ppm:
in acetone-d6: 7.45 d (1H, 3'-H, J = 3.8 Hz), 7.55 d
(1H, 4'-H, J = 3.8 Hz), 7.64–8.08 m (5H, Harom), 8.39 s
(1H, 3-H); in DMSO-d6: 7.55 d (1H, 4'-H, J = 3.8 Hz),
7.70 d (1H, 3'-H, J = 3.8 Hz), 7.87–8.22 m (5H, Harom),
8.76 s (1H, 3-H). Found, %: C 54.38; H 2.83; N 9.80.
C13H8N2O6. Calculated, %: C 54.18; H 2.79; N 9.72.
1-(4-Bromophenyl)-3-(4-nitro-2-furyl)-2-pro-
penone (IIc). Yield 11%, mp 189–190°C (from EtOH).
IR spectrum, ν, cm–1: 1608 (C=C); 1660 (C=O); 1525,
1
1367 (NO2). H NMR spectrum (acetone-d6), δ, ppm:
7.52 s (1H, 1-H), 7.53 d (1H, 2-H, J = 15.6 Hz), 7.74 d
(2H, m-H, J = 8.7 Hz), 7.77 d (1H, 3-H, J = 15.6 Hz),
8.03 d (2H, o-H, J = 8.7 Hz), 8.77 s (1H, 5'-H). Found,
%: C 48.31; H 2.57; Br 24.90; N 4.24. C13H8BrNO4.
Calculated, %: C 48.47; H 2.50; Br 24.80; N 4.34.
1-Methyl-2-nitro-3-(5-nitro-2-furyl)-2-pro-
penone (IIIg). Yield 56%, mp 176–177°C (from
AcOH). IR spectrum, ν, cm–1: 1660 (C=C); 1693
(C=O); 1560, 1362 (NO2). 1H NMR spectrum, δ, ppm:
in acetone-d6: 2.58 s (3H, Me), 7.34 d (1H, 3'-H, J =
3.8 Hz), 7.63 d (1H, 4'-H, J = 3.8 Hz), 7.87 s (1H,
3-H); in DMSO-d6: 7.65 d (1H, 3'-H, J = 4.0 Hz),
8.01 d (1H, 4'-H, J = 4.0 Hz), 8.34 s (1H, 3-H). Found,
%: C 42.52; H 2.61; N 12.50. C8H6N2O6. Calculated,
%: C 42.48; H 2.65; N 12.39.
3-(4-Nitro-2-furyl)-1-(4-tolyl)-2-propenone (IId).
Yield 29%, mp 148–149°C (from EtOH). IR spectrum,
ν, cm–1: 1620 (C=C); 1675 (C=O); 1536, 1365 (NO2).
1H NMR spectrum, δ, ppm: in acetone-d6: 2.43 s (3H,
Me), 7.38 d (2H, m-H, J = 8.0 Hz), 7.42 d (1H, 2-H,
J = 15.6 Hz), 7.52 s (1H, 1-H), 7.81 d (1H, 3-H, J =
15.6 Hz), 8.02 d (2H, o-H, J = 8.0 Hz), 8.80 s (1H,
5'-H); in DMSO-d6: 7.60 d (2H, m-H, J = 8.0 Hz),
7.65 s (1H, 1-H), 7.72 d (1H, 2-H, J = 15.0 Hz), 8.01 d
(1H, 3-H, J = 15.0 Hz), 8.23 d (2H, o-H, J = 8.0 Hz),
9.35 s (1H, 5'-H). Found, %: C 65.58; H 4.47; N 5.71.
C14H11NO4. Calculated, %: C 65.36; H 4.31; N 5.44.
1-Methyl-3-(5-methyl-2-furyl)-2-nitro-2-pro-
penone (IIIh). Yield 24%, mp 158–159°C (from
EtOH). IR spectrum, ν, cm–1: 1625 (C=C); 1660
(C=O); 1540, 1375 (NO2). 1H NMR spectrum, δ, ppm:
in acetone-d6: 2.35 s (3H, 5'-CH3), 2.45 s (3H, 1-CH3),
6.39 d (1H, 4'-H, J = 3.8 Hz), 7.08 d (1H, 3'-H, J =
3.8 Hz), 7.57 s (1H, 3-H); in DMSO-d6: 6.72 d (1H,
4'-H, J = 4.0 Hz), 7.43 d (1H, 3'-H, J = 4.0 Hz), 8.04 s
(1H, 3-H). Found, %: C 55.35; H 4.67; N 7.21.
C9H9NO4. Calculated, %: C 55.38; H 4.62; N 7.18.
1-(4-Methoxyphenyl)-3-(4-nitro-2-furyl)-2-pro-
penone (IIe). Yield 29%, mp 176–177°C (from ben-
zene). IR spectrum, ν, cm–1: 1620 (C=C); 1670 (C=O);
1
1545, 1370 (NO2). H NMR spectrum (CDCl3), δ,
ppm: 3.85 s (3H, OMe), 7.45 d (2H, m-H, J = 8.4 Hz),
7.58 s (1H, 1-H), 7.90 d (1H, 2-H, J = 16.0 Hz), 8.11 d
(1H, 3-H, J = 16.0 Hz), 8.49 d (2H, o-H, J = 8.4 Hz),
8.80 s (1H, 5'-H). Found, %: C 61.71; H 4.20; N 5.21.
C14H11NO5. Calculated, %: C 61.54; H 4.10; N 5.13.
3-(4-Nitro-2-furyl)acrylic acid (IIk). Yield 12%,
mp 216–217°C (from EtOH). IR spectrum, ν, cm–1:
1638 (C=C); 1690 (COO); 1530, 1367 (NO2). 1H NMR
spectrum (acetone-d6), δ, ppm: 6.50 d (1H, 2-H, J =
15.9 Hz), 7.43 s (1H, 1-H), 7.50 d (1H, 3-H, J =
15.9 Hz), 8.79 s (1H, 5'-H), 13.31 s (1H, COOH).
Found, %: C 45.97; H 2.85; N 7.61. C7H5NO5. Calcu-
lated, %: C 45.90; H 2.73; N 7.65.
2,4-Dinitrophenylhydrazones V (general proce-
dure). Aldehyde or ketone II or III, 1 mmol, was
dissolved on heating in 10–15 ml of diethyl ether, and
a hot solution of 1 mmol of 2,4-dinitrophenylhydrazine
in 5–10 ml of alcohol acidified with concentrated
hydrochloric acid (0.5–2 ml) was added. The mixture
was heated for 10–40 min, and the precipitate was
filtered off, washed in succession with water, alcohol,
and diethyl ether, and recrystallized from appropriate
solvent.
3-(4-Nitro-2-furyl)-2-propenal (IIl). Yield 18%,
mp 135–136°C (from CCl4). IR spectrum, ν, cm–1:
1634 (C=C); 1660 (C=O); 1530, 1370 (NO2). 1H NMR
spectrum, δ, ppm: in acetone-d6: 6.65 q (1H, 2-H, J =
16.1, 7.6 Hz), 7.53 s (1H, 1-H), 7.57 d (1H, 3-H, J =
16.1 Hz), 8.85 s (1H, 5'-H), 9.71 d (1H, CHO, J =
7.6 Hz); in DMSO-d6: 6.82 q (1H, 2-H, J = 17.0,
7.0 Hz), 7.82 d (1H, 3-H, J = 17.0 Hz), 7.93 s (1H,
1-H), 9.38 s (1H, 5'-H), 9.89 d (1H, CHO, J = 7.0 Hz).
Found, %: C 50.40; H 3.09; N 8.32. C7H5NO4. Calcu-
lated, %: C 50.30; H 3.01; N 8.38.
3-(4-Nitro-2-furyl)-1-phenyl-2-propenone 2,4-di-
nitrophenylhydrazone (Va). Yield 89%, mp 230–
231°C (from benzene). Found, %: N 16.47. C19H13N5O7.
Calculated, %: N 16.54.
1-(4-Chlorophenyl)-3-(4-nitro-2-furyl)-2-pro-
penone 2,4-dinitrophenylhydrazone (Vb). Yield 75%,
mp 199–200°C (from benzene). Found, %: Cl 7.68;
N 15.23. C19H12ClN5O7. Calculated, %: Cl 7.76;
N 15.30.
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SITKIN, KLIMENKO
428
5-Acetyl-4-(5-nitro-2-furyl)-1H-1,2,3-triazole
3-(4-Nitro-2-furyl)-1-(4-tolyl)-2-propenone 2,4-di-
(VIg). Yield 64%, mp 161–162°C. Found, %: C 43.23;
H 3.06; N 25.02. C8H6N4O4. Calculated, %: C 43.25;
H 2.72; N 25.21.
nitrophenylhydrazone (Vd). Yield 83%, mp 213–
214°C (from AcOH). Found, %: N 15.98. C20H15N5O7.
Calculated, %: N 16.02.
5-Acetyl-4-(5-methyl-2-furyl)-1H-1,2,3-triazole
(VIh). Yield 82%, mp 162–163°C. Found, %: C 56.45;
H 4.81; N 22.20. C9H9N3O2. Calculated, %: C 56.35;
H 4.64; N 21.89.
1-(4-Methoxyphenyl)-3-(4-nitro-2-furyl)-2-pro-
penone 2,4-dinitrophenylhydrazone (Ve). Yield 84%,
mp 208–209°C (from benzene). Found, %: N 15.39.
C20H15N5O8. Calculated, %: N 15.45.
The authors thank G.Kh. Khisamutdinov for con-
sulting on the synthesis of triazoles VI.
2-Nitro-3-(5-nitro-2-furyl)-1-phenyl-2-pro-
penone 2,4-dinitrophenylhydrazone (Vf). Yield 82%,
mp 257–258°C (from AcOH). Found, %: C 17.87.
C19H12N6O9. Calculated, %: C 17.95.
REFERENCES
1-Methyl-2-nitro-3-(5-nitro-2-furyl)-2-pro-
penone 2,4-dinitrophenylhydrazone (Vg). Yield 80%,
mp 255–256°C (from DMF). Found, %: N 20.63.
C14H10N6O9. Calculated, %: N 20.69.
1. Nazarova, Z.N. and Ustimenko, T.V., Zh. Obshch. Khim.,
1960, vol. 30, p. 2017.
2. Uspekhi khimii furana (Advances in the Furan Chem-
istry), Lukevits, E.Ya., Ed., Riga: Zinatne, 1978, p. 146.
1-Methyl-3-(5-methyl-2-furyl)-2-nitro-2-pro-
penone 2,4-dinitrophenylhydrazone (Vh). Yield 88%,
mp 217–218°C (from dioxane). Found, %: N 18.75.
C15H13N5O7. Calculated, %: N 18.67.
3. Shechter, H., Rec. Chem. Prog., 1964, vol. 25, p. 55.
4. Perekalin, V.V., Sopova, A.S., and Lipina, E.S.,
Nepredel’nye nitrosoedineniya (Unsaturated Nitro Com-
pounds), Leningrad: Khimiya, 1982, pp. 116, 117.
5. Savin, V.I., Flegontov, S.A., and Kitaev, Yu.P., Khim.
Geterotsikl. Soedin., 1972, p. 1331.
6. Cottee, F.H., Straughan, B.P., Timmons, C.J., Forbes, W.F.,
and Shilton, R., J. Chem Soc., 1967, p. 1146.
7. Minkin, V.I., Osipov, O.A., and Zhdanov, Yu.A.,
Dipol’nye momenty v organicheskoi khimii (Dipole
Moments in Organic Chemistry), Leningrad: Khimiya,
1968, pp. 49, 79.
8. Laboratorni technika organicke chemie, Keil, B., Ed.,
Praha: Československe Akademie Ved, 1963. Translated
under the title: Laboratornaya tekhnika organicheskoi
khimii, Moscow: Mir, 1966, p. 602.
9. Ponomarev, A.A., Sintezy i reaktsii furanovykh veshchestv
(Syntheses and Reactions of Furan Compounds), Saratov:
Saratov. Gos. Univ., 1959, p. 52; Lavrushin, V.F.,
Tsukerman, S.V., and Artemenko, A.I., Zh. Obshch.
Khim., 1962, vol. 32, pp. 1324, 1329.
3-(4-Nitro-2-furyl)-2-propenal 2,4-dinitrophenyl-
hydrazone (Vl). Yield 68%, mp 245–246°C (from
toluene). Found, %: N 20.51. C13H9N5O7. Calculated,
%: N 20.17.
5-Acyl-4-furyl-1H-1,2,3-triazoles (VI). A mixture
of 5 mmol of compound III and 5 mmol of sodium
azide in 20 ml of DMF was stirred for 3 h at 60–70°C,
cooled, diluted with water, and acidified to pH 1 with
10% hydrochloric acid. The precipitate was extracted
into diethyl ether, the extract was evaporated, and the
residue was recrystallized from glacial acetic acid.
5-Benzoyl-4-(5-nitro-2-furyl)-1H-1,2,3-triazole
(VIf). Yield 59%, mp 184–185°C. Found, %: C 54.90;
H 2.81; N 19.90. C13H8N4O4. Calculated, %: C 54.93;
H 2.83; N 19.71.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 41 No. 3 2005