Synthesis and photoinduced fluorescence of 3-(2-hetarylethenyl)chromen-2- ones

Article abstract of DOI:10.1134/S1070428008040210

3-(2-Hetarylethenyl)chromen-2-ones were synthesized for the first time, following two different schemes, and their spectral and photochemical properties were studied. The title compounds were found to undergo both reversible and irreversible photoinduced

Full text of DOI:10.1134/S1070428008040210

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2008, Vol. 44, No. 4, pp. 595–601. © Pleiades Publishing, Ltd., 2008.
Original Russian Text © A.Yu. Bochkov, V.N. Yarovenko, M.M. Krayushkin, T.A. Chibisova, T.M. Valova, V.A. Barachevskii, V.F. Traven’, I.P. Beletskaya,
2008, published in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 4, pp. 600–607.
Synthesis and Photoinduced Fluorescence
of 3-(2-Hetarylethenyl)chromen-2-ones
A. Yu. Bochkova, V. N. Yarovenkob, M. M. Krayushkinb, T. A. Chibisovaa, T. M. Valovac,
V. A. Barachevskiic, V. F. Traven’a, and I. P. Beletskayad
a Mendeleev Russian University of Chemical Technology, Miusskaya pl. 9, Moscow, 125047 Russia
e-mail: traven@muctr.ru
b Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, Moscow, Russia
c Photochemistry Center, Russian Academy of Sciences, Moscow, Russia
d Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow, Russia
Received August 2, 2007
Abstract—3-(2-Hetarylethenyl)chromen-2-ones were synthesized for the first time, following two different
schemes, and their spectral and photochemical properties were studied. The title compounds were found to
undergo both reversible and irreversible photoinduced transformations which are accompanied by considerable
change of the fluorescence pattern.
DOI: 10.1134/S1070428008040210
Interest in photochromic dihetarylethenes originates
from their possible application as materials for opto-
electronic devices, in particular for creation of high-
capacity optical data storage media [1]. Here, prefer-
ence is given to light-sensitive systems capable of
changing their fluorescence properties under the action
of actinic light [2].
molecule of a fluorophoric fragment, for example,
a coumarin moiety. It is known that many coumarin
derivatives are effective fluorophores characterized by
high fluorescence quantum yields [3]. Taking the
above stated into account, we were the first to syn-
thesize coumarine derivatives of the dihetarylethene
series. We obtained new unsymmetrical dihetaryl-
ethenes I containing coumarin and thiophene (or furan)
fragments.
A possible way of building up appropriate com-
pounds consists of introduction into a chromophoric
Scheme 1.
Ph
O
CHO
AcONa, Ac2O
OH
+
O
Ph
O
OH
OH
IV
O
III
Ph
Ph
Ph
NaBH4
TsOH
O
O
O
O
O
O
O
V
II
O
VI
595

BOCHKOV et al.
596
Scheme 2.
O
OH
O
Cl
O
Ar
SOCl2
ArH, AlCl3
O
O
O
O
O
O
VII
VIII
V, IXa, IXb
HO
Ar
Ar
β
α
NaBH4
TsOH
O
O
O
O
Xa, Xb
Ia, II
Ia, IXa, Xa, Ar = 2,5-dimethylthiophen-3-yl; II, V, Xb, Ar = Ph; IXb, Ar = 2-methyl-1-benzothiophen-3-yl.
There are no published data on the synthesis of
with (2-oxo-2H-chromen-3-yl)acetyl chloride (VIII).
(2-Oxo-2H-chromen-3-yl)acetic acid (VII) was syn-
thesized by reaction of salicylaldehyde with succinic
anhydride. The yield of acid VII was greater when
triethylamine rather than sodium succinate [7] was
used as base (57 and 40%, respectively). Treatment of
acid VII with excess thionyl chloride at room tempera-
ture (reaction time 12 h) gave (2-oxo-2H-chromen-3-
yl)acetyl chloride (VIII), and the latter was used to
acylate benzene in the presence of anhydrous alumi-
num chloride at 50°C (3 h). As a result, ketone V was
obtained in 75% yield (Scheme 2).
3-(2-hetarylethenyl)chromen-2-ones. Some synthetic
approaches to fluorescent arylethenes containing a cou-
marin fragment have been reported, but the available
data are contradictory. For example, various 3-styryl-
coumarin derivatives II were obtained according to
Scheme 1 [4]. Condensation of salicylaldehyde with
4-phenyl-4-oxobutanoic acid (III) gave butenolide IV
which underwent rearrangement into acyl coumarin
derivative under acidic [4, 6] or basic conditions [5].
However, the data on the product structure were am-
biguous. According to [5, 6], the product had 3-phen-
acylcoumarin structure V, whereas Chodankar et al.
[4] presumed formation of phenylacetyl-substituted
coumarin VI. In both cases, the assignment was based
only upon IR spectral data. We reproduced the syn-
thesis of compound V described in [4]. The physical
constants of butenolide IV differed from those
reported in [4], and the mass spectrum of ketone V
contained a peak with m/z 105, corresponding to ben-
zoyl ion. These data indicate that the rearrangement of
butenolide IV yields 3-phenacylcoumarin (V) rather
than 3-(phenylacetyl)coumarin (VI) as presumed in
[4]. The subsequent reduction of V with sodium tetra-
hydridoborate and dehydration of the alcohol thus
formed afforded 3-styrylcoumarin (II).
Following Scheme 2, we succeeded in synthesizing
heterocyclic analogs of 3-phenacylcoumarin (V). In
particular, the acylation of 2,5-dimethylthiophene and
2-methyl-1-benzothiophene with chloride VIII in the
presence of AlCl3 as catalyst at –5 to –10°C gave
ketones IXa and IXb in 71 and 63% yield, respec-
tively. The subsequent reduction of ketone IXa with
sodium tetrahydridoborate and dehydration of alcohol
Xa gave dihetarylethene Ia (Scheme 2). The reduction
of ketone IXb under analogous conditions occurred in
a complicated fashion, and we failed to isolate the cor-
responding alcohol.
One more synthetic approach to 3-styrylcoumarins
is based on the condensation of (2-oxo-2H-chromen-3-
yl)acetic acid (VII) with substituted benzaldehydes,
which leads to the formation of the target products in
one step (Scheme 3) [4]. Attack by the activated
methylene carbon atom in acid VII on the aldehyde
carbonyl group is followed by decarboxylation, yield-
ing disubstituted alkene.
However, analogous syntheses of heteroanalogs of
ketone V as key compounds for the preparation of new
photochromes (Scheme 1), cannot be regarded as
promising, for at least to steps in this scheme, the
formation of butenolide IV and its rearrangement into
ketone V, are characterized by fairly moderate yields
(45 and 52%, respectively). Therefore, we made an at-
tempt to reduce the number of steps and improve the
overall yield of ketone V and its heteroanalogs via
acylation of benzene and the corresponding hetarenes
We tried to extend this approach to the synthesis of
3-(2-hetarylethenyl)coumarins. In fact, by reaction of
acid VII with heterocyclic aldehydes in pyridine in the
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SYNTHESIS AND PHOTOINDUCED FLUORESCENCE
597
Scheme 3.
Table 1. Chemical shifts and coupling constants of protons
at the exocyclic double bond in 3-(2-hetarylethenyl)-2H-
chromen-2-ones Ia–If and II
Ar
β
α
ArCHO, pyridine, MW
Compound no.
δα, ppm
δβ, ppm
J, Hz
VII
Ia
Ib
Ic
Id
Ie
If
7.57
7.83
7.88
7.80
7.64
7.54
7.62
6.84
7.08
6.91
6.91
6.99
6.93
7.14
16.3
16.5
16.0
16.0
16.1
16.0
16.3
O
O
Ib–If
Ar = 2-methyl-1-benzothiophen-3-yl (b), 2-thienyl (c), 5-methyl-
thiophen-2-yl (d), 2-furyl (e), 5-methylfuran-2-yl (f).
presence of piperidine we obtained compounds Ib–If.
We also found that the reaction can be activated by
microwave irradiation. For example, the yield of com-
pound Ib in the thermal reaction (heating under reflux
on an oil bath) was as poor as 23%, while microwave-
assisted reaction gave 47% of Ib. In the latter case, the
isolation procedure was considerably simpler: no by-
products that could complicate chromatographic sepa-
ration of the target compounds were formed.
II
Table 2. Spectral parametersa of 3-(2-hetarylethenyl)-2H-
chromen-2-ones Ia–If and II
Comp.
no.
ε, l mol–1 ×
ΔD at ΔD at
λinit
λinit, nm
λph, nm
λfl, nm
cm–1
λph
Ia
Ib
Ic
Id
Ie
If
378
371
378
385
380
390
362
22200
11500
450
442
0.15 <0.1 452
0.15 <0.1 458
1
According to the H NMR data, all isolated com-
pounds I and II were trans isomers with respect to the
exocyclic double bond. Their H NMR spectra con-
tained two doublets at δ 7.88–7.70 and 7.08–6.84 ppm
with a coupling constant J of 16–16.5 Hz, which is
typical of trans-oriented protons (Table 1).
13000 <300< 0.25 <0.1 442
23700 <300< 0.51 <0.1 450
23400 <300< 0.03 <<0.1< 453
1
3
22200
28000
323
433
0.47 <0.1 465
0.92 ~0.1 440
II
We examined photochromic and fluorescent prop-
erties of 3-(2-hetaryl)coumarins Ia–If and II. Their
spectral parameters are collected in Table 2. It is seen
that these compounds are characterized by absorption
in the UV region and fluorescence in the visible
region. Irradiation induces photochemical transforma-
tions which are accompanied by reduction of the ab-
sorption and fluorescence intensity as compared to the
initial E isomer. Figures 1 and 2 show photoinduced
variations in the electronic absorption and fluorescence
spectra of compound Ib upon irradiation at λ 365 nm
(filtered light). Irradiation of a solution of Ib with UV
light (λ 365 nm) leads to reduction in the absorption
intensity at λ 371 nm and decrease in the fluorescence
intensity at λ 458 nm. Simultaneously, a weak absorp-
tion band appears in the visible region of the spectrum.
Analogous changes were observed for compounds Ia
and II. These transformations are reversible. Figure 3
illustrates variations of the spectral pattern upon ir-
radiation of a solution of the photoinduced form of
compound II with filtered light at λ 436 nm. However,
the intensity of the original absorption band is restored
only partly.
a
λinit, λph, and λfl stand for absorption maxima of the initial and
photoinduced forms and fluorescence maximum of the photo-
induced form; ε is the molar absorption coefficient of the initial
form, and ΔD stands for the photoinduced change in the optical
density at the absorption maxima corresponding to the initial
(λinit) and photoinduced forms (λph).
tra. On the other hand, new bands appear in the UV
region (Fig. 4). The photoinduced transformations are
also reversible. In the course of the reversible trans-
formations, the photoinduced optical density mono-
tonously decreases as a result of decomposition of the
initial photochrome or the corresponding photoinduced
form. This also follows from the disappearance of
isosbestic point from the absorption spectra after pro-
longed irradiation with actinic light. Compounds Ia
and Ib are characterized by high thermal stability of
the photoinduced form; the latter disappears in the dark
very slowly.
Taking into account that initial compounds Ia–If
and II have trans configuration, the observed photo-
chemical transformations may be rationalized as
follows using dihetarylethene Ib as an example
(Scheme 4). Presumably, the first step is E–Z isomer-
ization. Such isomerization is typical of trans-alkenes
The other compounds displayed no variations in the
in the visible region of the electronic absorption spec-
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BOCHKOV et al.
598
Scheme 4.
Me
O
O
S
O
O
hν1
hν2
hν3
hν4
H
Me
S
Me
S
O
O
E-Ib
Z-Ib
c-Ib
upon UV irradiation [8]. Photoinduced formation of
the Z isomer from compounds Ia, Ib, and II is likely to
promote the subsequent reversible photocyclization. In
fact, comparison of the observed variations in the
electronic absorption spectra of these compounds with
those typical of photoinduced electrocyclization of
dithienylethenes [1] suggests formation of cyclic struc-
tures. The appearance of a new absorption band at
longer wavelengths (Δλ = 70–72 nm, relative to λmax of
the initial structure) is typical of cyclic forms of di-
thienylethenes. In this case, the fluorescence intensity
decreases as a result of rupture of conjugation between
the coumarin and hetaryl fragments in going to the
cyclic structure.
tion. The results showed that the absorption maxima
of the Z isomers are displaced to the blue region by
20–30 nm as compared to the E isomers, which is
consistent with the experimental data. No transforma-
tions of compound Ie were observed upon irradiation.
Thus the results of our spectral and kinetic studies
indicate that the mechanism of photoinitiated trans-
formations of 3-(2-hetarylethenyl)coumarins is deter-
mined by the substrate structure. The process can
involve both reversible E–Z photoisomerization and
subsequent photocyclization. In all cases, the trans-
formations are accompanied by considerable change in
the fluorescence intensity, which may be useful for the
development of light-sensitive materials with photo-
controlled fluorescence.
It is most probable that compounds Ic, Id, and If do
not undergo photoinduced cyclization but give rise to
reversible E–Z photoisomerization, as follows from
the appearance of short-wave absorption bands in their
electronic spectra (Fig. 3), which is typical of cis-stil-
benes and their analogs [8]. The positions of absorp-
tion maxima of the E and Z isomers of compounds I
were calculated in terms of the INDO/S approxima-
EXPERIMENTAL
1
The H NMR spectra were measured on a Bruker
AC-200 spectrometer from solutions in CDCl3 and
DMSO-d6. The melting points were determined on
a Boetius melting point apparatus. The mass spectra
Ifl, rel. units
300
D
0.5
1
1
2
0.4
200
2
0.3
λ = 371 nm
7
0.2
100
4
λ = 442 nm
λ = 458 nm
0.1
0
0.1
300
350
400
450
500 λ, nm
400
500
600
λ, nm
Fig. 1. Electronic absorption spectra of a solution of
3-[(E)-2-(2-methyl-1-benzothiophen-3-yl)vinyl]-2H-chro-
men-2-one (Ib) in toluene (1) before and after irradiation at
λ 365 nm for (2) 5, (3) 10, (4) 15, (5) 20, (6) 30, and (7) 180 s.
Fig. 2. Fluorescence spectra of a solution of 3-[(E)-2-(2-
methyl-1-benzothiophen-3-yl)vinyl]-2H-chromen-2-one (Ib)
in toluene (1) before irradiation and after irradiation at
λ 365 nm for (2) 15, (3) 60, and (4) 105 s.
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SYNTHESIS AND PHOTOINDUCED FLUORESCENCE
599
D
(electron impact, 70 eV) were obtained on a Kratos
1.2
0.8
0.4
0.0
1
MS-30 instrument with direct sample admission into
the ion source. Thin-layer chromatography was per-
formed using Merck 60 F254 plates. The electronic
absorption spectra were recorded on a Varian Cary UV-
50 single-beam spectrophotometer. The fluorescence
spectra were measured on a Varian Cary Eclipse spec-
trofluorimeter. The spectral studies were performed
using 1-cm cells and toluene of spectroscopic grade as
solvent; solutions with a concentration of 4×10–5 M
(electronic absorption spectra) or 4×10–6 M (fluores-
cence spectra) were prepared. A mercury–xenon gas-
discharge lamp was used as a source of UV and visible
irradiation; a required wavelength was isolated using
a set of glass light filters. Microwave-assisted reactions
were carried out in a Rolsen MS1770SA domestic
microwave furnace.
6
2
6
2
300
400
500
λ, nm
Fig. 3. Electronic absorption spectra of a solution of
3-[(E)-2-phenylvinyl]-2H-chromen-2-one (II) in toluene
(1) before irradiation, (2) after irradiation at λ 365 nm for
210 s, and after subsequent irradiation at λ 436 nm for (3) 5,
(4) 15, (5) 30, and (6) 45 s.
5-(2-Hydroxybenzylidene)-3-phenylfuran-2(5H)-
one (IV). A mixture of 2.44 g (20 mmol) of salicyl-
aldehyde, 3.56 g (20 mmol) of 4-phenyl-4-oxobutanoic
acid [9], 1.64 g (20 mmol) of anhydrous sodium ace-
tate, and 7 ml of acetic anhydride was stirred for 12 h
on heating on a boiling water bath. The mixture was
poured into cold water and was left overnight, and the
precipitate was filtered off and recrystallized from
ethanol. Yield 2.4 g (45%), orange crystals, mp 172–
D
1.0
1
0.8
0.6
0.4
0.2
1
174°C; published data [4]: mp 140°C. H NMR spec-
trum (DMSO-d6), δ, ppm: 4.26 br.s (1H, OH), 6.64–
6.98 m (4H, Harom), 7.13 s (1H, 4′-H), 7.41–7.80 m
(6H, Harom). Mass spectrum, m/z (Irel, %): 264 (100)
[M]+, 158 (34), 118 (70), 105 (40). Calculated:
M 264.28.
λ = 323 nm
10
λ = 390 nm
3-(2-Oxoethyl-2-phenyl)-2H-chromen-2-one (V).
a. Butenolide IV, 4 g (15 mmol), was dissolved in
30 ml of acetic acid, an equal volume of concentrated
hydrochloric acid was added, and the mixture was
heated for 4 h on a boiling water bath. The mixture
was cooled, and the precipitate was filtered off and
recrystallized from ethyl acetate. Yield 2.08 g (52%),
colorless crystals, mp 165–166°C [5, 6].
0.0
300
400
500
λ, nm
Fig. 4. Electronic absorption spectra of a solution of
3-[(E)-2-(5-methylfuran-2-yl)vinyl]-2H-chromen-2-one (If)
in toluene (1) before irradiation and after irradiation at
λ 365 nm for (2) 5, (3) 15, (4) 30, (5) 45, (6) 60, (7) 120,
(8) 180, (9) 240, and (10) 300 s.
b. (2-Oxo-2H-chromen-3-yl)acetyl chloride (VIII),
4 mmol (880 mg), was dissolved in 20 ml of anhy-
drous benzene, 1200 mg (8.8 mmol) of AlCl3 was ad-
ded under stirring, and the mixture was stirred for 3 h
on heating on a boiling water bath. The warm mixture
was poured into a mixture of concentrated hydro-
chloric acid with ice, the organic phase was separated,
the aqueous phase was extracted with ethyl acetate, the
extract was combined with the organic phase and dried
over anhydrous MgSO4, the solvent was removed on
a rotary evaporator, and the residue was recrystallized
from ethyl acetate. Yield 790 mg (75%), colorless
crystals, mp 165–166°C [5, 6]. H NMR spectrum
1
(CDCl3), δ, ppm: 4.21 s (2H, CH2), 7.22–8.03 m (10H,
Harom). Mass spectrum, m/z (Irel, %): 264 (10) [M]+,
105 (100) [PhCO]+, 76 (63), 51 (25). Found, %:
C 77.29; H 4.62. C17H12O3. Calculated, %: C 77.26;
H 4.58. M 264.28.
3-(2-Hydroxy-2-phenylethyl)-2H-chromen-2-one
(Xb). Ketone V, 132 mg (0.5 mmol), was dissolved in
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BOCHKOV et al.
600
15 ml of methanol, and sodium tetrahydridoborate was
added in 50-mg portions at 1-h intervals, the progress
of the reaction being monitored by TLC. When the re-
action was complete, the mixture was poured into cold
water and acidified with 5 ml of 10% hydrochloric
acid. The precipitate was filtered off, dried, and recrys-
tallized from 75% ethanol. Yield 108 mg (81%), color-
less crystals, mp 179–180°C; published data [4]:
(2-Oxo-2H-chromen-3-yl)acetyl chloride (VIII).
(2-Oxo-2H-chromen-3-yl)acetic acid (VII), 204 mg
(1 mmol), was dispersed in 10 ml of anhydrous meth-
ylene chloride, and 360 mg (3 mmol) of thionyl chlo-
ride and 2 drops of dimethylformamide were added.
After 12 h, the transparent solution was evaporated on
a rotary evaporator to obtain acid chloride VIII as yel-
low–brown crystals which were used in further syn-
theses without additional purification.
1
mp 155°C. H NMR spectrum (CDCl3), δ, ppm:
2.56 br.s (1H, OH), 2.85–3.11 m (2H, CH2), 5.07–
5.13 m (1H, CHOH), 7.20–7.51 m (10H, Harom). Mass
spectrum, m/z (Irel, %): 266 (10) [M]+, 160 (23), 107
(100) [PhCH2O]+. Found, %: C 76.50; H 5.39.
C17H14O3. Calculated, %: C 76.68; H 5.30. M 266.30.
3-[2-(2,5-Dimethylthiophen-3-yl)-2-oxoethyl]-
2H-chromen-2-one (IXa). A solution of 667 mg
(3 mmol) of (2-oxo-2H-chromen-3-yl)acetyl chloride
(VIII) and 308 mg (2.75 mmol) of 2,5-dimethyl-
thiophene in 50 ml of anhydrous methylene chloride
was cooled to –10°C using an ice–salt bath, 850 mg
(6.3 mmol) of AlCl3 was added in portions under
stirring over a period of 15 min, and the mixture was
stirred for 2.5 h on cooling and poured into a mixture
of concentrated hydrochloric acid with ice. The or-
ganic phase was separated and dried over anhydrous
magnesium sulfate, the solvent was removed on
a rotary evaporator, and the residue was recrystallized
from petroleum ether–acetone (1:1). Yield 71%, color-
3-[(E)-2-Phenylvinyl]-2H-chromen-2-one (II).
p-Toluenesulfonic acid, 100 mg, was added to a solu-
tion of 133 mg (0.5 mmol) of compound Xb in 5 ml of
acetic acid, and the mixture was kept for 24 h at room
temperature and poured into water. The precipitate was
filtered off and purified by column chromatography
using methylene chloride as eluent. Yield 113 mg
(91%), greenish crystals, mp 168–169°C; published
1
data [4]: mp 166°C. H NMR spectrum (CDCl3), δ,
1
less crystals, mp 155–156°C. H NMR spectrum
ppm: 7.14 d (1H, β-H, J = 16.3 Hz), 7.24–7.54 m (9H,
Harom), 7.62 d (1H, α-H, J = 16.3 Hz), 7.81 s (1H, 4-H,
chromene). Mass spectrum, m/z (Irel, %): 248 (100)
[M]+, 231 (18), 219 (31), 203 (15), 189 (21), 165 (13).
Found, %: C 82.07; H 4.98. C17H12O2. Calculated, %:
C 82.24; H 4.87. M 248.28.
(CDCl3), δ, ppm: 2.43 s (3H, 5′-CH3), 2.68 s (3H,
2′-CH3), 4.07 s (2H, CH2), 7.15 s (1H, 4′-H), 7.27–
7.50 m (4H, 5-H, 6-H, 7-H, 8-H), 7.66 s (1H, 4-H).
Mass spectrum, m/z (Irel, %): 298 (12) [M]+, 187 (13),
139 (100). Found, %: C 68.36; H 4.88; S 10.59.
C17H14O3S. Calculated, %: C 68.44; H 4.73; S 10.75.
M 298.36.
(2-Oxo-2H-chromen-3-yl)acetic acid (VII).
A mixture of 30 g (0.3 mol) of succinic anhydride,
12.2 g (0.1 mol) of salicylaldehyde, and 13.1 g
(0.13 mol) of triethylamine was heated under stirring
to the boiling point. After 1–1.5 h, abundant solid
separated. The mixture was cooled and treated with
concentrated hydrochloric acid, and the precipitate was
filtered off and dried. The product was dissolved in
a warm saturated aqueous solution of sodium hydrogen
carbonate, the solution was filtered, finely powdered
activated charcoal was added to the filtrate, the mix-
ture was stirred for 15 min and filtered, and the filtrate
was acidified with concentrated hydrochloric acid. The
precipitate was filtered off, washed with water, and
dried in air until constant weight. Yield 11.2 g (57%),
colorless crystals, mp 163–164°C; published data [7]:
mp 164°C. 1H NMR spectrum (CDCl3), δ, ppm: 3.66 s
(2H, CH2), 7.29–7.57 m (4H, 5-H, 6-H, 7-H, 8-H),
7.70 s (1H, 4-H). Mass spectrum, m/z (Irel, %): 204
(25) [M]+, 160 (100) [M – CO2]+, 131 (71).
3-[2-(2-Methyl-1-benzothiophen-3-yl)-2-oxo-
ethyl]-2H-chromen-2-one (IXb) was synthesized as
described above for compound IXa by acylation of
2-methyl-2-benzothiophene with acyl chloride VIII.
Yield 61%, colorless crystals, mp 185–186°C. 1H NMR
spectrum (CDCl3), δ, ppm: 2.84 s (3H, Me), 4.21 s
(2H, CH2), 7.27–7.81 m (9H, Harom). Mass spectrum,
m/z (Irel, %): 336 (30) [M]+, 296 (31), 205 (25), 175
(100). Found, %: C 71.86; H 4.19; S 9.55. C20H14O3S.
Calculated, %: C 71.84; H 4.22; S 9.59. M 334.40.
3-[2-(2,5-Dimethylthiophen-3-yl)-2-hydroxy-
ethyl]-2H-chromen-2-one (Xa) was synthesized as
described above for alcohol Xb from ketone IXa.
Yield 74%, colorless crystals, mp 167–168°C. 1H NMR
spectrum (CDCl3), δ, ppm: 2.34 s (3H, 5′-CH3),
2.37 br.s (1H, OH), 2.41 s (3H, 2′-СH3), 2.92–2.95 m
(2H, CH2), 5.07–5.13 m (1H, CHOH), 6.75 s (1H,
4′-H), 7.50–7.27 m (4H, 5-H, 6-H, 7-H, 8-H), 7.53 s
(1H, 4-H). Mass spectrum, m/z (Irel, %): 300 (4) [M]+,
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SYNTHESIS AND PHOTOINDUCED FLUORESCENCE
601
160 (18), 141 (100), 131 (15), 113 (62). Found, %:
C 68.12; H 5.42; S 10.79. C17H16O3S. Calculated, %:
C 67.98; H 5.37; S 10.67. M 300.38.
3-[(E)-2-(5-Methylthiophen-2-yl)vinyl]-2H-
chromen-2-one (Id). Yield 41%, yellow crystals,
mp 166–167°C. H NMR spectrum (CDCl3), δ, ppm:
1
2.51 s (3H, Me), 6.69 d (1H, 4′-H, J = 3.4 Hz), 6.91 d
(1H, β-H, J = 16 Hz), 6.96 d (1H, 3′-H, J = 3.5 Hz),
7.52–7.25 m (4H, 5-H, 6-H, 7-H, 8-H), 7.69 s (1H,
4-H), 7.80 d (1H, α-H, J = 16 Hz). Mass spectrum, m/z
(Irel, %): 268 (100) [M]+. Found, %: C 71.70; H 4.35;
S 12.03. C16H12O2S. Calculated, %: C 71.62; H 4.51;
S 11.95. M 268.34.
3-[(E)-2-(2,5-Dimethyltiophen-3-yl)vinyl]-2H-
chromen-2-one (Ia) was synthesized as described
above for alkene II from alcohol Xa. Yield 97%,
1
yellow crystals, mp 154–155°C. H NMR spectrum
(CDCl3), δ, ppm: 2.43 s (3H, 5′-CH3), 2.50 s (3H,
2′-CH3), 6.84 d (1H, β-H, J = 16.3 Hz), 6.94 (1H,
4′-H), 7.49–7.27 m (4H, 5-H, 6-H, 7-H, 8-H), 7.57 d
(1H, α-H, J = 16.3 Hz), 7.73 s (1H, 4-H). Mass spec-
trum, m/z (Irel, %): 282 (100) [M]+. Found, %: C 72.15;
H 4.91; S 11.51. C17H14O2S. Calculated, %: C 72.31;
H 5.00; S 11.36. M 282.36.
3-[(E)-2-(2-Furyl)vinyl]-2H-chromen-2-one (Ie).
1
Yield 36%, yellow crystals, mp 142–143°C. H NMR
spectrum (CDCl3), δ, ppm: 6.99 d (1H, β-H, J =
16.1 Hz), 7.25–7.53 m (7H, Harom), 7.64 d (1H, α-H,
J = 16.1 Hz), 7.70 s (1H, 4-H). Mass spectrum, m/z
(Irel, %): 238 (73) [M]+, 181 (100). Found, %: C 75.49;
H 4.20. C15H10O3. Calculated, %: C 75.62; H 4.23.
M 238.25.
Condensation of (2-oxo-2H-chromen-3-yl)acetic
acid (VII) with aldehydes (general procedure).
An ampule was charged with 1 mmol of the corre-
sponding heterocyclic aldehyde, 1.1 mmol of acid VII,
and 2 ml of pyridine, two drops of piperidine was
added, and the ampule was tightly capped with a heat-
resistant stopper and irradiated for 20 min in a micro-
wave furnace at a power of 210 W. The mixture was
cooled and poured into ice water acidified with hydro-
chloric acid. The precipitate was filtered off or ex-
tracted into methylene chloride, and the product was
finally purified by column chromatography using
methylene chloride as eluent.
3-[(E)-2-(5-Methylfuran-2-yl)vinyl]-2H-chro-
men-2-one (If). Yield 42%, orange crystals, mp 151–
1
152°C. H NMR spectrum (CDCl3), δ, ppm: 2.37 s
(3H, Me), 6.05 d (1H, 4′-H, J = 2.8 Hz), 6.36 d (1H,
3′-H, J = 3.1 Hz), 6.93 d (1H, β-H, J = 16.0 Hz), 7.28–
7.53 m (4H, 5-H, 6-H, 7-H, 8-H), 7.54 d (1H, α-H,
J = 16.0 Hz), 7.68 s (1H, 4-H). Mass spectrum, m/z
(Irel, %): 252 (100) [M]+, 237 (17), 209 (15), 181 (55),
152 (43). Found, %: C 75.98; H 4.94. C16H12O3. Cal-
culated, %: C 76.18; H 4.79. M 252.27.
3-[(E)-2-(2-Methyl-1-benzothiophen-3-yl)vinyl]-
2H-chromen-2-one (Ib). Yield 47%, yellow crystals
1
with greenish tint, mp 183–184°C. H NMR spectrum
REFERENCES
(CDCl3), δ, ppm: 2.70 s (3H, Me), 7.08 d (1H, β-H,
J = 16.5 Hz), 7.27–7.55 m (6H, Harom), 7.78 d (1H,
Harom, J = 7.9 Hz), 7.82 s (1H, 4-H), 7.83 d (1H, α-H,
J = 16.5 Hz), 7.98 d (1H, Harom, J = 8.0 Hz). Mass
spectrum, m/z (Irel, %): 318 (100) [M]+, 258 (16), 184
(23), 171 (25), 67 (20), 43 (38). Found, %: C 75.40;
H 4.47; S 9.99. C20H14O2S. Calculated, %: C 75.45;
H 4.43; S 10.07. M 318.40.
1. Irie, M., Chem. Rev., 2000, vol. 100, p. 1685.
2. Tian, H. and Yang, S., Chem. Soc. Rev., 2004, vol. 33,
p. 85.
3. Kuznetsova, N.A. and Kaliya, A.L., Usp. Khim., 1992,
vol. 61, p. 1243.
4. Chodankar, N.K., Joshi, S.D., Sequeria, S., and Se-
hadri, S., Indian J. Chem., 1987, vol. 26, p. 427.
5. Walter, R., Theodoropoulos, D., and Purcell, T.C., J. Org.
Chem., 1967, vol. 32, p. 1649.
3-[(E)-2-(2-Thienyl)vinyl]-2H-chromen-2-one
(Ic). Yield 51%, yellow crystals, mp 157–158°C.
1H NMR spectrum (CDCl3), δ, ppm: 6.91 d (1H, β-H,
J = 16 Hz), 7.02–7.54 m (7H, Harom), 7.72 s (1H, 4-H),
7.88 d (1H, α-H, J = 16 Hz). Mass spectrum, m/z
(Irel, %): 254 (100) [M]+. Found, %: C 70.81; H 4.00;
S 12.42. C15H10O2S. Calculated, %: C 70.85; H 3.96;
S 12.61. M 254.31.
6. Baltazzi, E. and Davis, E.A., Chem. Ind., 1962, p. 1653.
7. Chodankar, N.K. and Sehadri, S., Dyes Pigm., 1985,
vol. 6, p. 313.
8. Waldeck, D.H., Chem. Rev., 1991, vol. 91, p. 415.
9. Somerville, L.F. and Allen, C.F.H., Org. Synth., 1933,
vol. 13, p. 12.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 44 No. 4 2008