Tetronic acid in reaction with aromatic aldehydes and 2-naphthylamine. Investigation of fluorescent and nonlinear-optical characteristics of compounds obtained

Article abstract of DOI:10.1134/S1070428008070142

By Knoevenagel condensation and by three-component condensation 3-arylmethylenetetrahydrofuran-2,4-diones and previously unknown 8,11-dihydro-11-arylbenzo[f]furo[3,4-b]quinolin-10(7H)-ones were respectively synthesized. The luminescent spectra and nonline

Full text of DOI:10.1134/S1070428008070142

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 7, pp. 1031−1037. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © N.G. Kozlov, S.L. Bondarev, A.P. Kadutskii, L.I. Basalaeva, F.S. Pashkovskii, 2008, published in Zhurnal Organicheskoi Khimii,
2008, Vol. 44, No. 7, pp. 1041−1047.
Tetronic acid in Reaction with Aromatic Aldehydes
and 2-Naphthylamine. Investigation of Fluorescent
and Nonlinear-Optical Characteristics of Compounds Obtained
N. G. Kozlova, S. L. Bondarevb, A. P. Kadutskiia, L. I. Basalaevaa, and F. S. Pashkovskiic
aInstitute of Physical Organic Chemistry, National Academy of Sciences of Belarus, Minsk, 220072 Belarus
e-mail: loc@ifoch.bas-net.by
bInstitute ofMolecular and Atomic Physics, National Academy of Sciences of Belarus, Minsk, Belarus
cInstitute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received July 3, 2007
Abstract—By Knoevenagel condensation and by three-component condensation 3-arylmethylenetetrahydrofuran-
2,4-diones and previously unknown 8,11-dihydro-11-arylbenzo[f]furo[3,4-b]quinolin-10(7H)-ones were
respectively synthesized. The luminescent spectra and nonlinear-optical characteristics of compounds obtained
were investigated.
DOI: 10.1134/S1070428008070142
is catalyzed by the proton of the enolyzed β-dicarbonyl
compound I.
Tetrahydrofuran-2,4-dione (I) widely known as
β-tetronic acid is a promising convenient building block
for the synthesis of structures of lignan type that attract
a constant scientific and practical interest as components
of a group of naturally occurring compounds [1–3] and
as organic luminophors with fused five- and six-
membered heterocycles [4]. In the series of these com-
pounds azaanalogs exist of lignan structures whose
synthesis occurs in two stages. The first stage consists
in the preparation of 3-arylmethylenefurandiones, the
second one, in their condensation with aromatic amines.
By boiling of compounds Va–Vk with 2-naphthyl-
amine in alcohol solution for 20–40 min we obtained
8,11-dihydro-11-arylbenzo[f]furo[3,4-b]quinolin-10(7H)-
ones VIa–VIk. The same compounds we synthesized by
a three-component condensation of tetrahydrofuran-2,4-
dione (I), aromatic aldehydes IIa–IIk, and 2-naph-
thylamine (III) at the simultaneous charge of all
components or by boiling in alcohol of two of these
components followed by adding the third one after
15 min without isolation of intermediate reaction
products. The boiling of the tetrahydrofuran-2,4-dione
with an aromatic aldehyde with subsequent charging
2-naphthylamine into the reaction mixture or boiling
the 2-naphthylamine with aldehyde followed by addition
of the tetronic acid led to the formation of 8,11-dihydro-
11-arylbenzo[f]furo[3,4-b]quinolin-10(7H)-ones VIa–
VIk. The formation of the same reaction products at the
different order of reagents charging suggests that the
formation of benzo[f]furoquinolines occurs both via
azomethines of 2-naphthylamine series IV (as has been
already reported in [5, 6]) and through cross-conjugated
tetrahydrofuran-2,4-diones V. In the second event
unstable iminium intermediate A decomposes into
3-arylidenetetrahydrofuran-2,4-dione V and 2-naphthyl-
amine. The latter again enters into the addition reaction
The target of the present study was the preparation of
3-arylmethylenetetrahydrofuran-2,4-diones Va–Vk
proceeding from tetronic acid (I) and aromatic aldehydes
IIa–IIk, the reaction of compounds Va–Vk with 2-naph-
thylamine (III) and the three-component condensation
involving tetronic acid, aromatic aldehydes and 2-napht-
hylamine, and the investigation of luminescent spectra
and nonlinear-optical characteristics of compounds
obtained.
The Knoevenagel condensation of equimolar quan-
tities of tetronic acid (I) and aromatic aldehydes IIa–IIk
by heating the reagents mixture in alcohol led to the
formation in preparative amounts of the target 3-aryl-
methylenetetrahydrofuran-2,4-diones Va–Vk. In this reac-
tion the formation of the cross-conjugated multiple bond
1031

KOZLOV et al.
1032
Scheme 1.
R
NH2
R
O
O
N
O
O
IIa_IIk
III
I
IV
I
O
O
O
O
O
R
O
_III
R
NH
Va_Vk
III
A
O
R
2
O
R
3
4
1
O
11
10
O
O
H2N
5
N
8
6
H
VIa_VIk
B
R = H (a), Cl (b), Br (c), OH (d), OCH3 (e), N(CH3)2 (f), N(C2H5)2 (g), 3,4-(OCH3)2 (h), 3-OCH3-4-one (i), 3-OC2H5-
4-one (j), 3,4-OCH2O (k).
Scheme 2.
O
O
O
O
O
9
10
8
7
NaNO2 / H+
O
NH2NH2
1
2
VIk
NH2
N
3
O
H
6
N
N
5
OH
VIk
VIIIk
with β-dicarbonyl compound V at the carbon atom in
the α-position to the amino group. The heterocyclization
of the arising intermediate compound B results in
compounds VIa–VIk (Scheme 1).
acid fragment, and in the structure of the final condensa-
tion products VIa–VIk the lactone moiety is conserved
remaining available for further modification of the
compounds.
The intramolecular cyclization of aminoketone B
involves exclusively the ketone carbonyl of the tetronic
On oxidation of compound Vk with sodium nitrite in
acetic acid we obtained benzo[f]furo[3,4-b]-quinolin-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008

TETRONIC ACID IN REACTION WITH AROMATIC ALDEHYDES
1033
10(8H)-one (VIIk), whose lactone ring at treating with
hydrazine in alcoholic solution opened virtually
quantitatively to yield the corresponding hydrazide of
1,3-disubstituted benzo[f]quinoline-2-carboxylic acid
VIIIk (Scheme 2). Hence this sequence of transforma-
tions can be an efficient and convenient method of
preparation of 1,2,3-substituted derivatives of benzo-
[f]quinoline.
3240 cm–1 appears in the spectra of compounds Vi, Vj,
Vid, VIi, VIj, and VIIIk.
The comparison of yields of compounds VIa–VIk
reported in EXPERIMENTAL permits the establishment
of some trends in the condensation. The electrophilic
groups in the para-position of the benzene ring of
arylmethylenefurandiones Vb and Vc decrease the
electron density on the exocyclic carbon of the double
bond facilitating the addition of 2-naphthylamine, and
thus the yield of compounds Vb and Vc reaches 82 and
84%. The nucleophilic substituent in the benzene rings
of arylidenefurandiones Vd–Vg through the π-con-
jugation with the double bond increase the electron
density on the reaction site of compounds V and hamper
the formation of the new C–C bond. Therefore the yield
of compounds VId–VIg does not exceed 58%. The yield
of the reaction products is favored by nucleophilic
substituents in the meta-position of the benzene ring of
disubstituted aldehydes when the second nucleophilic
substituent is located in the para-position. Yields of 8,11-
dihydro-11-(4-hydroxy-3-methoxyphenyl)- (VIi) and
8,11-dihydro-11-(4-hydroxy-3-ethoxyphenyl)- (VIj) -
benzo[f]furo[3,4-b]quinolin-10(7H)-ones equal respec-
tively 82 and 78% and are by 30% higher than the yield
of 8,11-dihydro-11-(4-hydroxyphenyl)benzo[f]furo[3,4-
b]quinolin-10(7H)-one (VId), for the presence of the
substituents in the meta-position reduces the donor effect
of the hydroxy group due to the distortion of the
coplanarity of dione V molecule [8].
The composition and structure of obtained compounds
Vi, Vj, VIa–VIk, VIIk, and VIIIk were confirmed by
elemental analyses, 1H NMR and IR spectra.
1H NMR spectra of compounds Vi and Vj contain
two characteristic singlets of methylene protons of the
heterocycle in the region 4.60–4.65 and 4.85–4.90 ppm
due to the presence of Ε- and Z-geometric isomers in the
1
ratio 2:3. In H NMR spectra of compounds VIa–VIk
singlets characteristic of these structures are observed
from the protons H11 and NH at 5.43–5.69 and 9.89–
10.31 ppm respectively [7]. The signal from the protons
of CH2OCO group appeared in the spectrum as a doublet
of doublets at 4.72–4.95 ppm. The chemical shifts and
multiplicity of these signals unambiguously confirm the
1
structure of compounds VIa–VIk. H NMR spectrum
of oxidation product VIIk lacks the signal from NH
group evidencing the complete dehydrogenation. In the
1H NMR spectrum of hydrazide VIIIk a singlet of the
alcoholic hydroxy group appears at 9.27 ppm. The
protons at the nitrogen atoms give rise to two char-
acteristic multiplet in the region 4.60–4.82 (2H) and
4.95–5.30 (1H) ppm.
The effect of the character of substituent in the bezene
ring of aromatic aldehydes on the position of the absorp-
tion bands in the electronic spectra (λmax) and their
relative intensity is also revealed in the electronic spectra
recorded from ethanol solutions at room temperature.
The spectral data are presented in the table and on Figs.
1 and 2. The spectra of dihydrobenzofuroquinolinones
VIc, VIg, VIh, VIj, and VIk are characterized mainly
by a system of three electron-vibronic bands located
respectively in the ranges 300–380, 250–300, and 200–
250 nm (see the table and Fig. 1), they possess a pro-
nounced vibronic structure, and the strongest band is that
in the short-wave region with λmax ~ 220 nm. 3-Aryl-
methylenetetrahydrofuran-2,4-diones Va, Vf, Vg, and Vh
are characterized by absorption spectra displaced into
the long-wave region compared to those of compounds
VI. The most longwave bands are observed in the spectra
of compounds Vg and Vf with λmax 483 and 480 nm
respectively (see the table and Fig. 1). The red shift of
the long-wave absorption bands in the series of com-
pounds Va (335 nm), Vh (385 nm), Vf (480 nm), and Vg
In the IR spectra of 3-arylmethylenetetrahydrofuran-
2,4-diones Vi and Vj absorption bands are present of the
stretching vibrations of the keto and lactone carbonyls
in the range 1740–1730 cm–1 and of the double bond
conjugated with them in the region 1635–1640 cm–1. The
IR spectra of compounds VIa–VIk, and VIIk contain
the bands of stretching vibrations of the lactone carbonyl
at 1720–1745 cm–1 and of a conjugated double bond in
the region 1640–1670 cm–1. The band of the secondary
amino group is observed in the range 3330–3180 cm–1
in the spectra of compounds VIa–VIk. IR spectrum of
compound VIb is characterized by the absorption band
at 854 cm–1 belonging to C–Cl bond, of compound VIc,
by the strong band at 562 cm–1 characteristic of the
stretching vibrations of the C–Br bond. A strong
absorption band in the region 2850–2830 cm–1 belonging
to vibrations of OCH3 group is present in the spectra of
compounds Vi, VIe, VIh, and VIi. The absorption band
of the stretching vibrations of the hydroxy group at 3400–
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008

KOZLOV et al.
1034
Spectral and luminescence properties of compounds Va, Vf, Vg, Vh and VIc, VIg, VIh, VIj, VI k in ethanol solution and
polycrystals at room temperaturea
Compound
no.
Absorption λmax, nm ( )
Fluorescence λmax, nm
polycrystals
ethanol
ethanol
383 w
Va
335 (0.21), 235 (1.0)
410 m
Vf
480 (1.0), 248 (0.46), 226 (0.57)
520 w
513 w
394 w
381 m
513 w
380 m
381 m
380 m
692 m
648 s
Vg
483 (1.0), 258 (0.16), 233 (0.14)
Vh
385 (1.0), 248 (0.46)
415, 558 m
449 s
VIc
VIg
VIh
VIj
VIk
350 (0.08), 326 (0.13), 283 (0.39), 224 (1.0)
483 (1.0), 258 (0.16), 233 (0.14)
648 s
350 (0.08), 325 (0.13), 283 (0.37), 224 (1.0)
350 (0.09), 325 (0.15), 281 (0.41), 223 (1.0)
350 (0.09), 325 (0.15), 282 (0.41), 225(1.0)
406 s
395 s
409 s
a All compounds under study in the crystalline state at room temperature exhibit fluorescence of various intensity. The registration of
fluorescence spectra of compounds Vf and Vg was performed at λexcit 460 nm, and of all the other compounds, at λexcit 340 nm. Intense
fluorescence (s) is characteristic of compounds Vg, VIc, VIg, VIh, VIj, VI k. The other compounds possess medium (m) intensity of
fluorescence. Maxima of the fluorescence spectra vary in a wide spectral range. Whereas for the majority of polycrystals the fluorescence
maxima lie about 410 nm, compounds Vf and Vg fluoresce in the long-wave region at 645 and 692 nm (Fig. 2).
(483 nm) is apparently caused by increased interaction
with charge transfer between electron-donor groups
OCH3, N(CH3)2, N(CH5)2 and the electron-acceptor
furandiones [9]. As a result of the increased interaction
with the charge transfer in the spectra of compounds Vf–
Vh the intensity of the long-wave absorption bands is
stronger that the intensity of the short-wave bands in the
range 220–240 nm (see the table). In the spectrum of
compound Va lacking electron-donor substituents the
intensity of the band at 235 nm is 5 times higher than
that of the long-wave band at 335 nm.
8,11-Dihydro-11-(arylphenyl)benzo[f]furo[3,4-b]-
quinolin-10(7H)-ones VIc, VIg, VIh, VIj, VI kin ethanol
solution at room temperature and λexcit 340 nm exhibit
medium intensity fluorescence with the maximum in the
region 380–390 nm (see the table). The fluorescence of
weak intensity is also characteristic of furandione type
compounds in ethanol solution, and the spectral maxima
of compounds Vf and Vg (λexcit 460 nm) are strongly
displaced to the long-wave region compared to the spectra
of compounds from the benzofuroquinoline series VIc,
VIg, VIh, VIj, VI k (see the table and Fig. 2).
Fig. 2. Absorption (1, 4) and fluorescence (2, 3, 5, 6) spectra
of compounds VIj (1–3) and Vf (4–6) in ethanol (1, 2, 4, 5)
and polycrystals (3, 6) at 293 K.
Fig. 1. Electron absorption spectra registered at 293K in
ethanol of compounds (1) VIc, (2) Vh, (3) Vf.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008

TETRONIC ACID IN REACTION WITH AROMATIC ALDEHYDES
1035
(2Harom), 7.90 m (1H, C=CH), 8.52 m (1Harom). Found,
%: C 59.47; H 4.51. C12H10O5. Calculated, %: C 59.46;
H 4.50.
Compounds Vf and Vg in the polycrystalline state
possess nonlinear-optical properties, namely, they are
capable of transforming the frequency of a laser radiation.
At excitation with the first harmonic of the radiation of
neodymium laserYAG–Nd3+ (λexcit 1.06 μm, Εexcit 80 mJ,
pulse length 20 ns) of these polycrystalline compounds
a bright red fluorescence, λmax ~640 nm (Vg), and dark-
red fluorescence, λmax ~690 nm (Vf) was observed. This
fluorescence arises as a result of simultaneous absorption
of two photons (λ 1.06 m) and is two-photon excited.
(E,Z)-3-(4-Hydroxy-3-ethoxybenzylidene)-tetra-
hydrofuran-2,4-dione (Vj). Yield 62%, yellow crystals.
IR spectrum, cm–1: 3387, 3008, 2943, 1730, 1703, 1664,
1635, 1527, 1482, 1317, 1302, 1219, 1113. 1H NMR
spectrum, δ, ppm: 3.95 s (3H, OMe), 4.65 s (2H, CH2,
Ε-isomer), 4.90 s (2H, CH2, Z-isomer), 7.06 m (2Harom),
7.87 m (1H, C=CH), 8.55 m (1Harom). Found, %: C 62.89;
H 4.82. C13H12O5. Calculated, %: C 62.90; H 4.83.
The discovered nonlinear-optical effect of two-photon
excitation for compounds Vf and Vg suggests them as
promising materials for designing elements for visualiza-
tion of the invisible radiation of IR lasers.
8,11-Dihydro-11-arylbenzo[f]furo[3,4-b]-quinolin-
10(7H)-ones VIa–VIk. a. Asolution of 1.43 g (0.01 mol)
of 2-naphthylamine (III), 0.01 mol of an appropriate
aromatic aldehyde IIa–IIk, and 1.3 g (0.01 mol) of
tetronic acid (I) in 20 ml of ethanol was boiled till the
beginning of crystals precipitation (30–60 min). On
cooling the separated precipitate was filtered off, washed
with ether, and recrystallized from a mixture ethanol–
benzene, 1:1.
EXPERIMENTAL
Electron absorption spectra were registered at room
temperature on a spectrophotometer Cary-500 (Varian,
USA). Fluorescence spectra were measured on a spectro-
fluorimeter SFL-1211A (SOLAR, Belarus’). The two-
photon excitation was performed with the use of the first
harmonic of the radiation of neodymium laser YAG–
Nd3+, wave length 1.06 μm. IR spectra were recorded on
b. Asolution of 1.43 g (0.01 mol) of 2-naphthylamine
(III), 0.01 mol of an appropriate aromatic aldehyde IIa–
IIk in 20 ml of ethanol or a solution of 0.01 mol of
aldehyde IIa–IIk and 1.3 g (0.01 mol) of tetronic acid
(I) in 20 ml of ethanol was boiled for 15 min, 10 min
later into the reaction mixture was added respectively
either 1.3 g (0.01 mol) tetronic acid (I) or 1.43 g
(0.01 mol) of 2-naphthylamine (III), and the boiling was
continued for 20–40 min. On cooling the separated
precipitate was filtered off, washed with ether, and
recrystallized from a mixture ethanol–benzene, 1:1.
'
'
a Fourier spectrophotometer Nicolet Protege-460 from
thin films or pellets with KBr. NMR spectra were
obtained on a spectrometer Bruker AC-500 [500 (1H),
125 MHz (13C)] using 5% solutions in DMSO-d6,
chemical shifts measured from an internal reference
TMS.
Tetrahydrofuran-2,4-dione (tetronic acid) was
prepared along procedure [10] by bromination of ethyl
acetoacetate followed by rearrangement of the α-bromide
obtained into a γ-isomer under the effect of air oxygen
and cyclization of the γ-isomer under the treatment with
aqueous alkali.
c. A solution of 0.01 mol of an appropriate 3-aryl-
methylene-2,4(3H,5H)-furandione Va–Vk and 0.01 mol
2-naphthylamine (III) in 20 ml of ethanol was boiled till
the beginning of crystals precipitation. On cooling the
separated precipitate was filtered off, washed with ether,
and recrystallized from a mixture ethanol–benzene, 1:1.
8,11-Dihydro-11-phenylbenzo[f]furo[3,4-b]-
quinolin-10(7H)-one (VIa). Yield 72%, colorless
crystals, mp 270°C. IR spectrum, cm–1: 3220, 3190, 1718,
1642, 1590, 1541, 1470, 1442, 1361, 1235, 1100, 813.
1H NMR spectrum, δ, ppm: 4.90 d.d (2H, CH2OCO),
5.43 s (1H, CH), 6.80–7.10, 7.20–7.43, 7.60–7.90 m
(11Harom), 10.12 s (1H, NH). Found, %: C 80.53; H 4.80;
N 4.43. C21H15NO2. Calculated, %: C 80.51; H 4.79;
N 4.47.
3-Arylmethylenetetrahydrofuran-2,4-diones Va–
Vk were obtained by boiling in alcohol equimolar
amounts of tetronic acid (I) and an appropriate aldehyde
IIa–IIk for 20–30 min. Physicochemical constants of
β-dicarbonyl compounds Va–Vh, and Vk coincide with
the published data [11, 12], the parameters of new
compounds Vi and Vj are given below.
(E,Z)-3-(4-Hydroxy-3-methoxybenzylidene)-
tetrahydrofuran-2,4-dione (Vi). Yield 71%, yellow
crystals. IR spectrum, cm–1: 3400, 3010, 2920, 2830,
1740, 1682, 1640, 1523, 1481, 1320, 1306, 1225, 1100.
1H NMR spectrum, δ, ppm: 3.93 s (3H, OMe), 4.60 s
(2H, CH2, Ε-isomer), 4.85 s (2H, CH2, Z-isomer), 7.02 m
8,11-Dihydro-11-(4-chlorophenyl)benzo[f]furo-
[3,4-b]quinolin-10(7H)-one (VIb). Yield 82%, colorless
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008

KOZLOV et al.
1036
crystals, mp 295°C. IR spectrum, cm–1: 3229, 1726, 1645,
1541, 1520, 1468, 1321, 1223, 1080, 854, 813. 1H NMR
spectrum, δ, ppm: 4.93 d.d (2H, CH2OCO), 5.69 s (1H,
CH), 7.00–7.20, 7.26–7.57, 7.67–8.10 m (10Harom),
10.31 s (1H, NH). Found, %: C 72.60; H 4.02; Cl 10.10;
N 4.04. C21H14ClNO2. Calculated, %: C 72.62; H 4.03;
Cl 10.08; N 4.03.
3294, 2185, 2010, 1727, 1711, 1689, 1532, 1472, 1376,
1334, 1235, 992, 573. 1H NMR spectrum, δ, ppm: 1.09 t
(6H, 2CH2Me), 3.25 q (4H, 2CH2Me), 4.78 d.d (2H,
CH2OCO), 5.47 s (1H, CH), 6.35–6.52 m (2Harom), 6.88–
7.09 m (2Harom), 7.18–7.35 m (3Harom), 7.61–7.77 m
(3Harom), 9.89 s (1H, NH). Found, %: C 78.11; H 6.24;
N 7.31. C25H24N2O2. Calculated, %: C 78.12; H 6.25;
N 7.29.
8,11-Dihydro-11-(4-bromophenyl)benzo[f]furo-
[3,4-b]quinolin-10(7H)-one (VIc). Yield 84%, colorless
crystals, mp 340°C. IR spectrum, cm–1: 3230, 1720, 1647,
1531, 1513, 1484, 1213, 1011, 743, 562. 1H NMR spec-
trum, δ, ppm: 4.95 d.d (2H, CH2OCO), 5.64 s (1H, CH),
7.00–7.20, 7.26–7.57, 7.67–8.10 m (10Harom), 10.31 s
(1H, NH). Found, %: C 64.29; H 3.60; Br 20.38; N 3.60.
C21H14BrNO2. Calculated, %: C 64.28; H 3.57; Br 20.41;
N 3.57.
8,11-Dihydro-11-(3,4-dimethoxyphenyl)benzo[f]-
furo[3,4-b]quinolin-10(7H)-one (VIh). Yield 50%,
colorless crystals, mp 238°C. IR spectrum, cm–1: 3310,
3230, 2843, 2213, 2126, 2051, 1722, 1693, 1660, 1524,
1
1471, 1368, 1325, 1211, 967, 564. H NMR spectrum,
δ, ppm: 3.65 (6H, 2OMe), 4.92 d.d (2H, CH2OCO),
5.61 s (1H, CH), 6.42–6.68 m (2Harom), 7.00 s (1Harom),
7.20–7.36 m (3Harom), 7.62–7.81 m (3Harom), 9.95 s (1H,
NH). Found, %: C 73.80; H 5.36; N 3.72. C23H20NO4.
Calculated, %: C 73.79; H 5.34; N 3.74.
8,11-Dihydro-11-(4-hydroxyphenyl)benzo-
[f]furo[3,4-b]quinolin-10(7H)-one (VId). Yield 47%,
colorless crystals, mp 268–269°C. IR spectrum, cm–1:
3330, 3307, 1750, 1731, 1640, 1536, 1479, 1324, 1217,
8,11-Dihydro-11-(4-hydroxy-3-methoxyphenyl)-
benzo[f]furo[3,4-b]quinolin-10(7H)-one (VIi). Yield
82%, colorless crystals, mp 298–300°C. IR spectrum,
cm–1: 3338, 3315, 3268, 2846, 2739, 1745, 1662, 1643,
1
1008, 560. H NMR spectrum, δ, ppm: 4.80 d.d (2H,
CH2OCO), 5.52 s (1H, CH), 6.12–6.56 m (2Harom), 6.90–
7.05 m (2Harom), 7.18–7.40 m (3Harom), 7.62–7.85 m
(3Harom), 8.64 (1H, OH), 10.00 s (1H, NH). Found, %:
C 76.60; H 4.56; N 4.21. C21H15NO3. Calculated, %:
C 76.59; H 4.56; N 4.25.
1
1529, 1513, 1472, 1325, 1218, 1009, 565. H NMR
spectrum, δ, ppm: 3.20 s (3H, OMe), 4.90 d.d (2H,
CH2OCO), 5.58 s (1H, CH), 6.39 d (1Harom), 6.57 d
(1Harom), 6.95 s (1Harom), 7.25–7.40 m (3Harom), 7.85 m
(3Harom), 8.68 s (1H, OH), 10.20 s (1H, NH). Found, %:
C 73.34; H 4.98; N 3.87. C22H18NO4. Calculated, %:
C 73.33; H 5.00; N 3.89.
8,11-Dihydro-11-(4-methoxyphenyl)benzo-
[f]furo[3,4-b]quinolin-10(7H)-one (VIe). Yield 47%,
colorless crystals, mp 278°C. IR spectrum, cm–1: 3326,
3310, 2850, 2744, 1743, 1667, 1532, 1515, 1482, 1319,
1
8,11-Dihydro-11-(4-hydroxy-3-ethoxyphenyl)-
benzo[f]furo[3,4-b]quinolin-10(7H)-one (VIj). Yield
78%, colorless crystals, mp 268–270°C. IR spectrum,
cm–1: 3324, 3318, 3262, 2831, 2745, 1739, 1658, 1642,
1534, 1513, 1471, 1319, 1216, 1010, 562. 1H NMR
spectrum, δ, ppm: 1.28 t (3H, OCH2Me), 3.90 m (2H,
OCH2Me), 4.90 d.d (2H, CH2OCO), 5.57 s (1H, CH),
6.39 d (1Harom), 6.53 d (1Harom), 6.92 s (1Harom), 7.25–
7.38 m (3Harom), 7.87 m (3Harom), 8.59 s (1H, OH), 10.19
s (1H, NH). Found, %: C 73.80; H 5.35; N 3.73.
C23H20NO4. Calculated, %: C 73.79; H 5.34; N 3.74.
1225, 973, 552. H NMR spectrum, δ, ppm: 3.18 s (3H,
OMε), 4.72 d.d (2H, CH2OCO), 5.49 s (1H, CH), 6.10–
6.48 m (2Harom), 6.90–7.08 m (2Harom), 7.22–7.34 m
(3Harom), 7.60–7.73 m (3Harom), 10.08 s (1H, NH). Found,
%: C 77.00; H 4.95; N 4.10. C22H17NO3. Calculated, %:
C 76.96; H 4.95; N 4.08.
8,11-Dihydro-11-(4-dimethylaminophenyl)benzo-
[f]furo[3,4-b]quinolin-10(7H)-one (VIf). Yield 58%,
colorless crystals, mp 224°C. IR spectrum, cm–1: 3321,
3307, 2236, 2054, 1715, 1703, 1662, 1513, 1484, 1387,
1312, 1222, 964, 542. 1H NMR spectrum, δ, ppm: 2.75 s
(6H, 2Me), 4.80 d.d (2H, CH2OCO), 5.50 s (1H, CH),
6.40–6.60 m, 7.00–7.40, 7.60–7.80 m (10Harom), 9.95 s
(1H, NH). Found, %: C 77.54; H 5.60; N 7.88.
C23H20N2O2. Calculated, %: C 77.52; H 5.62; N 7.86.
8,11-Dihydro-11-(3,4-methylenedioxyphenyl)-
benzo[f]furo[3,4-b]quinolin-10(7H)-one (VIk). Yield
84%, colorless crystals, mp 330°C. IR spectrum, cm–1:
3278, 3250, 1724, 1650, 1618, 1598, 1526, 1485, 1467,
1431, 1353, 1248, 1211, 1028, 1012, 813. 1H NMR
spectrum, δ, ppm: 4.80 d.d (2H, CH2OCO), 5.60 s (1H,
CH), 5.87 d (2H, OCH2O), 6.60–6.65 m (3Harom), 7.20–
8,11-Dihydro-11-(4-diethylaminophenyl)benzo-
[f]furo[3,4-b]quinolin-10(7H)-one (VIg). Yield 54%,
colorless crystals, mp 300°C. IR spectrum, cm–1: 3329,
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008

TETRONIC ACID IN REACTION WITH AROMATIC ALDEHYDES
1037
ACKNOWLEDGMENT
7.38 m (3Harom), 7.70–7.80 m (3Harom), 9.98 s (1H, NH).
Found, %: C 73.96; H 4.22, N 3.90. C22H15NO4.
Calculated, %: C 73.95; H 4.20; N 3.92.
The authors express their gratitude to I.I. Kalosha
for the help in the nonlinear-optical measurements and
to A.P. Stupak for registering the fluorescence spectra.
11-(1,3-Benzodioxol-5-yl)benzo[f]furo[3,4-b]-
quinolin-10(8H)-one (VIIk). To a solution of 1.1 g
(3 mmol) of compound VIk in 5 ml of acetic acid and
2 ml of hydrochloric acid was added 0.28 (4 mmol) of
sodium nitrite, and the mixture was stirred at room
temperature for 40 min. The reaction mixture was
neutralized with a saturated solution of sodium hydrogen
carbonate, the separated precipitate was filtered off and
recrystallized from DMF. Yield 0.93 g (86%), colorless
crystals, mp 295°C. IR spectrum, cm–1: 1740, 1214, 1012.
1H NMR spectrum, δ, ppm: 5.47 s (2H, C8H), 6.18 s
(2H, OCH2O), 6.70–8.40 m (9HapOm). Found, %: C 74.39;
H 3.66; N 3.93. C22H13NO4. Calculated, %: C 74.36;
H 3.69; N 3.94.
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1-(1,3-Benzodioxol-5-yl)-3-(hydroxymethyl)-
benzo[f]quinoline-2-carbohydrazide (VIIIk).
A mixture of 0.36 g (1 mmol) of compound VIIk and 1
ml of hydrazine hydrate in 15 ml of ethanol was boiled
for 1 h. On cooling the separated precipitate was filtered
off, washed with ethanol (3 × 5 ml), and recrystallized
from DMF. Yield 0.37 g (95%), colorless crystals, mp
220°C (decomp.). IR spectrum, cm–1: 3337, 3192, 1626,
1
1479, 1231, 1036. H NMR spectrum, δ, ppm: 4.22 s
(2H, CH2OH), 4.60–4.82 m (2H, NHNH2), 4.95–5.30 m
(1H, NHNH2), 6.14 s (2H, OCH2O), 6.65–8.25 m
(9Harom), 9.27 s (1H, OH). Found, %: C 68.19; H 4.45;
N 10.89. C22H17N3O4. Calculated, %: C 68.21; H 4.42;
N 10.85.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 7 2008