Synthesis of Polycyclic Heteroaromatic Coumarins via Photoinduced Dehydrogenative Annulation of 4-Phenyl-3-heteroarylcoumarins

Article abstract of DOI:10.1021/acs.joc.8b02290

An efficient, oxidant and metal-free synthesis of polycyclic heteroaromatic coumarins was developed. H-Furo[2′,3′:3,4]naphtho[2,1-c]chromen-4-one (2a-2f), 1H-benzofuro[2′,3′:3,4]naphtho[2,1-c]chromen-1-one (2g-2j), and 4H-thieno[2′,3′:3,4]naphtho[2,1-c]ch

Full text of DOI:10.1021/acs.joc.8b02290

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Article
Synthesis of polycyclic heteroaromatic coumarins via photoinduced
dehydrogenative annulation of 4-phenyl-3-heteroarylcoumarins
Juan Shi, Yang Kang, Tao Wang, Yong Liang, and Zunting Zhang
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b02290 • Publication Date (Web): 23 Oct 2018
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Synthesis of polycyclic heteroaromatic coumarins via photoinduced
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dehydrogenative annulation of 4-phenyl-3-heteroarylcoumarins
Juan Shi,†‡ Yang Kang,† Tao Wang,† Yong Liang,†§ Zunting Zhang*†
†Key Laboratory of the Ministry of Education for Medicinal Resources and Natural
Pharmaceutical Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal
University, Xi’an 710119, People’s Republic of China.
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‡Shaanxi Key Laboratory of Catalysis, School of Chemical and Environmental Sciences, Shaanxi
University of Technology, Hanzhong 723001, People’s Republic of China.
ABSTRACT: An efficient, oxidant and metal free synthesis of polycyclic heteroaromatic
coumarins
was
developed.
H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one
(2a-2f),
1H-benzofuro[2',3':3,4]naphtho[2,1-c]chromen-1-one (2g-2j) and 4H-thieno[2',3':3,4]naphtho
[2,1-c]chromen-4-one (2k-2s) derivatives were obtained by the irradiation of 4-phenyl-3-
heteroarylcoumarin in EtOH–H2O (9 : 1, v/v) using a high-pressure Hg lamp as the light source, at
room temperature and under Ar atmosphere. Owing to the expansion of π-conjugation system,
2a-2s showed strong fluorescence emissions in ethanol solution (ФF = 0.40-0.83).
INTRODUCTION:
In recent years, π-expanded coumarins have attracted considerable attention due to their excellent
pharmacological activities. Polycyclic conjugated coumarins, for examples, Isofraxidin isolated
from Acanthopanax Senticosus and Calanolides isolated from Calophyllum Lanigerum trees, were
found to be highly effective autumnariol and against HIV-1, respectively.1 Besides, coumarin
derivatives have been widely used in the field of fluorescent dyes, organic light-emitting materials,
solar battery and liquid crystal materials due to their outstanding photophysical and photochemical
properties.2 The type of fused ring, the manner of fusion and the electronic effect from
electron-donating or electron-withdrawing substituents all influenced the photophysical
parameters. It has been showed that the introduction of fused rings constituted a powerful
approach to control photophysical properties of π-expanded coumarins.3 A variety of aromatic
[c]coumarin derivatives along a few heterocoumarin analogues are shown in Scheme 1, which
possess photophysical activity, especially compound e (ФF = 0.73).4
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Scheme 1. Reported π-expanded coumarins with their corresponding ФF (n.r.: not reported)
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The photoinduced intramolecular annulation of polycyclic compounds could be summarized
mainly in three strategies: (a) photoinduced oxidative annulation with the presence of external
oxidizer, e.g. O2, I2 or TCNE;5 (b) transition metal-catalyzed dehydrogenative photocyclization,
which might need additional ligand or other metals;6 (c) dehydrohalogenation or dehydrated
photocyclization.7 For instances, irradiation of 3,4-diphenylcoumarin in benzene with the presence
of iodine for 40 hours by a medium pressure mercury lamp gave photooxidation product
benzo[b]phenanthro[9,10-d]pyran-9-one in decent yield (Scheme 2a).5a The synthesis of
polycyclic indole derivatives was achieved via intramolecular direct double C-H activation in the
presence of Co(dmgH)2(4-CO2Mepy)Cl and Ir(ppy)3 under visible light irradiation along with the
elimination of hydrogen (Scheme 2b).6c In Scheme 2c, a non-oxidative photocyclization was
performed by exposing lactam to sunlight in the presence of diisopropylethylamine to provide the
desired indolocarbazole. The photochemically induced conversion was promoted by the facile
dehydrobromination of the incipient cyclization product.7c
Scheme 2. Examples of photoinduced intramolecular annulation
We have successfully demonstrated the transition-metal and/or additive-free photoinduced
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intramolecular cyclization.8 Various heteroaromatics were synthesized from 1-aryl-2-(furan/
thiophen-2-yl)butan-1,3-diones9 and 2,3-di(hetero)-arylchromen-4-ones.10 Encouraged by our
previous work and the excellent photophysical properties of π-expanded coumarins, we would like
to report the synthesis of polycyclic heteroaromatic coumarins 2 via photoinduced
dehydrogenative annulation of 4-phenyl-3-heteroaryl-coumarins 1 (Scheme 3). Moreover, the
fluorescence properties of 2 were further explored and high fluorescence quantum efficiencies (ФF
= 0.40-0.83) were observed and discussed, which could be explained by the π-expanded
conjugation system.
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Scheme 3. Photoinduced syntheses of 2 via dehydrogenative annulation
RESULTS and DISCUSSION
Substrates 1a-1s were synthesized according to the literature reports.11 The full UV-absorption
spectrum of 1a is shown in SI. And the typical π→π* absorption is observed at 370 nm (ε =
104700 L·mol−1·cm−1), which is accordant with the excited light (365 nm) of a high-pressure
mercury lamp.
Table 1. Optimization of Intramolecular cyclization of 1aa
Conc.
(mM)
Time Conva Yielda
Entry
Solvent (v:v)
(h)
2
(%)
30
50
80
84
88
81
74
(%)
12
40
50
57
64
61
59
1
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7
2.5
2.5
2.5
2.5
2.5
2.5
2.5
CH2Cl2
MeCN
2
MeOH
2
EtOH
2
EtOH-H2O (9:1)
EtOH-H2O (8:1)
EtOH-H2O (6:1)
2
2
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EtOH-H2O (9:1)
EtOH-H2O (9:1)
EtOH-H2O (9:1)
EtOH-H2O (9:1)
EtOH-H2O (9:1)
EtOH-H2O (9:1)
2
2
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2
82
70
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39
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13b
2.5
2.5
2.5
2.5
69
97
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a Irradiation of 1a (0.25 mmol) in various solvents (100 mL) with a 500 W high-pressure mercury lamp under Ar
atmosphere at room temperature. b Performed in the open air atmosphere.
Initially, irradiation of 1a (0.25 mmol) in CH2Cl2 (100 mL) with a high-pressure mercury lamp
(500 W) at ambient temperature for 2 h gave annulation product 2a in 12% (Table 1, entry 1).
Replacement of DCM with acetonitrile, methanol or ethanol gave 2a in better yields (40%, 50%
and 57%, entries 2-4). Interestingly, the yields of 2a were slightly elevated with addition water to
the reaction mixture (59-64%, entries 5-7), while the conversion yields varies. The effects of
substrate concentration and irradiation time were investigated. Thus, the annulation with either
higher or lower substrate concentrations of 1a was performed. Unfortunately, 2a was obtained in
reduced yields (entries 8-9). As it is expected, the conversion yields of 1a were increased
dramatically with extended irradiation time (entries 11-12), whereas, the yields for the formation
of 2a decreased slightly, especially in the presence of air (entry 13). As a result, the irradiation of
1a (0.25 mM) in EtOH-H2O (9:1, v/v, 100 mL) with mercury lamp under Ar atmosphere at room
temperature for 2 h was determined to be the optimal condition.
With the optimized condition determined, a series of annulation products 2a-2s were obtained
and displayed in Table 2 along with yields in parenthesis. Generally, substrates 1 bearing
benzofuran (1g-1j) and thiophene (1k-1s) gave the corresponding cyclization products in higher
yields (52-76%) than that of the furan derivatives (2a-2f). And substrates with electron-donating
groups (e.g. Me, OMe, and C2H5), produced better yields than the substrate bearing
electron-withdrawing groups (F, CF3). Notably, a free hydroxyl group could also be tolerated and
2o was obtained in 39%. The presence of Cl group on 2e makes it possible to perform further
modification.
Table 2. Synthesis of polycyclic heteroaromatic coumarins (2a−2s) a
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a
All reactions were carried out on 0.25 mmol of 1 in EtOH-H2O (100 mL, 9 : 1) and irradiated with a
high-pressure mercury lamp (500 W) under an argon atmosphere at ambient temperature.
1
The structure of 2 was established via H NMR, 13C NMR, HRMS, UV and IR. Compound 2l
was also analyzed by X-ray. The fluorescence spectra of 2 were measured in EtOH (10-6 mol/L)
and the corresponding excitation/emission maxima wavelength and quantum yields were listed in
Table 3. Generally, irradiation of coumarin derivatives 2 with 303–370 nm light generated
blue-purple fluorescence light (λem = 417−465 nm).
The quantum yields (ФF) of 4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-ones (2a-2f) are higher
than those bearing thiophenyl moiety (2k-2s). Due to the presence of expanded π-conjugated
system, 2g-2j gave higher quantum yields than 2a-2f. The presence of electron-donating
substituent on heteroaromatic coumarins benefited the growth of quantum yields. For example,
2g-2j have prominent fluorescence properties, and their fluorescence quantum yields are ranging
from 0.76 to 0.83 with significant stokes shifts (140 to 149 nm). The quantum yield of 2g is
consistent with literature reported (0.73/benzene). 5a
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Table 3 Spectral properties of 2a-2s in ethanol solution(10-6 mol/L)
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Stokes
Compounds
shift/nm
ФF
2a
2b
2c
2d
2e
2f
347
351
303
299
304
349
313
316
319
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318
341
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308
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321
319
370
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449
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447
457
462
465
462
456
439
439
439
455
443
430
417
449
444
452
102
98
0.64
0.72
0.76
0.78
0.53
0.63
0.78
0.81
0.83
0.76
0.51
0.63
0.67
0.54
0.40
0.43
0.65
0.71
0.62
0.51
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146
145
143
108
149
149
143
140
123
123
121
114
124
122
98
2g
2h
2i
2j
2k
2l
2m
2n
2o
2p
2q
2r
128
125
74
2s
1a
The crystal structure of 2l was characterized by the single crystal X-ray diffraction, and the
detail info is shown in Table S1(SI). As illustrated in Figure 1, the molecule of 2l includes three
benzene rings [A (C1-C6), C (C8, C9, C12, C13, C18, C19), and D (C13-C18)], one
2H-pyran-2-one ring B (C6, O1, C7, C8, C19, C1) and one thiophene ring E (C9, S1, C10, C11,
C12). The atoms of ring B, ring C, ring D and ring E are almost coplanar with a mean deviation
from the least-squares plane of 0.0853 A˚. It is important to note that the unexpected rotation
(17.6˚) of ring A from the planar B-E was observed, which is believed to avoid steric conflicts
between H2 and H17.
Figure 1. X-ray crystal structure of 2l
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On the basis of literature reports and experimental evidence, a plausible mechanism for the
formation of 2 is proposed and illustrated in Scheme 4. Irradiation of 3-(furan-2-yl)-4-
phenylcoumarin (1a) with UV light (365 nm) at ambient temperature generates the intermediate A
via an intramolecular 6π-electron-cyclization.12 A undergoes [1,5]-H shift and gives the
intermediate B.13 The rearomatization of the furan ring is the force driving this [1,5]-sigmatropic
shift.
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The keto-enol tautomerization of A leads to the formation of intermediate B, which might be
stabilized via the intramolecular hydrogen bond between the corresponding -OH and oxygen from
furan ring and it is believed to be the driving force for this transformation. Then, syn-isomer
intermediate C was obtained from another enol-keto tautomerization. Because polar protic solvent
is beneficial to the process of keto-enol isomerization, account for the higher yield of 2a in
EtOH-H2O (9:1) comparing to CH2Cl2 and MeCN. And the dose water is benefit to the keto-enol
isomerization. Finally, syn-isomer C yields annulation product 2a by the hydrogen evolution,
which share similar concept with literature reports.10 It is important to note that the cyclization
product 2a was obtained with the presence of oxygen (open air) in low yield. Thus we concluded
the intramolecular photoinduced dehydrogenative cyclization proceeded through the S1 state.
More importantly, by-product H2 was also successfully detected via GC chromatography during
the annulation, which powerfully proved the validity of the proposed mechanism (SI, Figure
S4-5).
Scheme 4. Proposed mechanism for the formation of 2a
In order to further examine and validate the mechanism, 3,4-diphenyl-2H-chromen-2-
one
3 was subjected to the optimal condition [hv, rt, 9 : 1 EtOH/H2O (v/v)]. However,
neither annulation product benzo[b]phenanthro-[9,10-d]pyran-9-one nor H2 was detected.
It is a strong indication that our reported photoinduced cyclization proceed via different
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mechanism comparing to the literature report.5a Due to the presence of benzene ring at both
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3
and 4 position of substrate 3, there is no significant electron density difference between
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the phenyl substituents. Thus, no cyclization product was observed under the optimal
condition.
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The presence of furyl or thiophenyl group at 3-position of coumarin is believe to be
crucial for the cyclization of substrates
heteroaromatic at the position as well as the electron withdrawing property of the
carbonyl group, the electron density difference between and facilitate the cyclization
1. With the presence of electron rich five-member
3
3
4
and yield the intramolecular dehydrogenative product
that irradiation of 3-phenyl-4-(furan-2-yl)coumarin
2
. Meanwhile, it is important to note
4
in EtOH–H2O (9 : 1, v/v) with a
high-pressure mercury lamp at room temperature under Ar atmosphere also led to the
formation of dehydrogenative cyclization product [5H-furo[2',3':3,4]naphtho[1,2-c]
chromen-5-one]
3,4-di(furan-2-yl)coumarin
presence of same substituents at both
5
but in lower yields (30%). As expected, irradiation of
failed to give corresponding cyclization product due to the
and position. On the basis of experimental result,
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3
4
only substrates with different aryl substitutions gave cyclization product in decent to good
yields and the 3-heteroarylcoumarin seems to be the best candidate due to the consistency
with electron withdrawing property of carbonyl group. (Scheme 5)
Scheme 5. Effect of the substituents on dehydrogenative annulation reactivity
In addition, treatment of 1a with NaBH4 in EtOH at 35 °C for 8 h give reduced product
in 31% (Scheme 6).14 As it is expected that subjection of
7
7
to the optimal condition [hv, rt,
9 : 1 EtOH/H2O(v/v)] failed to provide dehydrogenative annulation product
be easily explained by the lack of keto-enol tautomerization.
8, which could
Scheme 6. Attempted annulation of 7 under the optimal reaction conditions
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CONCLUSION
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In summary, we have successfully demonstrated the synthesis of polycyclic heteroaromatic
coumarins via photoinduced dehydrogenative annulation of 3-aryl-4-heteroarylcoumarins
with a high-pressure mercury lamp in EtOH-H2O (9:1, v/v) at room temperature.
Compared with reported methods, the described method has the superiorities of a) no
requirement of oxidant, additives and catalyst, b) green solvent (EtOH-H2O), c) broad
substrate scope, and d) moderate to very good atom efficiency. Owing to π-expanded
conjugated system, heteroaromatics 2a-2s possess excellent fluorescence in ethanol
solution.
EXPERIMENTAL PROCEDURES AND ANALYTICAL DATA
General Information. All reagents were purchased from commercial suppliers and used without purification.
Thin-layer chromatography (TLC) used silica gel 60 GF254 plate. The silica gel (size 200-300 mesh) used for the
column chromatography was purchased from Qingdao Haiyang Chemistry Plant (China). Melting points were
1
measured in a X-5 micro-melting point apparatus and were uncorrected. H NMR spectra were recorded on 400
MHz spectrometer with TMS as internal reference and CDCl3 or DMSO-d6 as solvent. All chemical shift values
were reported in parts per million (ppm) and referenced to the residual solvent peaks [CDCl3 (7.26 ppm) or
1
DMSO-d6 (2.50 ppm)] for H NMR. 13C NMR spectra were recorded on 400 or 600 MHz spectrometer and the
CDCl3 (77.16 ppm) or DMSO-d6 (39.52 ppm) for 13C NMR spectra, with coupling constant (J) values reported in
Hz. The infrared spectra were recorded on a Nicollet 170SX FTIR spectrophotometer with KBr pellets in the
4000–500 cm-1 region. High-resolution mass spectrometry (HRMS) was recorded using electron-spray ionization
quadrupole-time of flight (ESI-Q-TOF) technique. The elemental analysis were carried out with a Perkin-Elmer
240C elemental analyzer. The crystal diffraction data was collected on a Bruker Smart-1000 CCD diffractometer.
The fluorescence spectra were measured on a Hitachif-4600 fluorescence spectrometer equipped with a xenon
discharge lamp.
General Procedures for Syntheses of Polycyclic Heteroaromatic Coumarins (2a−2s).
Substrate 3-(furan-2-yl)-4-phenyl-2H-chromen-2-one 1a (72 mg, 0.25 mmol) was dissolved in a mixture of
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EtOH-H2O (100 mL, 9:1, v/v) at ambient temperature in a quartz tube (100 mL). The solution was deaerated by
bubbling argon for 30 min and irradiated with a high pressure mercury lamp (500 W), which was cooled to about
25 °C with tap water by means of an internal cold finger. Then, the volatiles were removed under reduced pressure
and residue was column chromatographied (ethyl acetate/petroleum ether, 1:20) to give 2a (46 mg, 64%).
Analogously, compounds 2b-2s were synthesized using the same methodology described above, with yields
39~74%. (The reaction scheme is in SI-Scheme S1).
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Procedures for Syntheses of 4-aryl-3-heteroaryl-2H-chromen-2-one derivatives (1a-1s, 3, 4,
6).
Synthesis of 3-bromo-4-hydroxy-2H-chromen-2-ones16 The N-bromosuccinimide (2.9 g, 16.2 mmol)
was added to a solution of 4-hydroxycoumarin (2.496 g, 15.4 mmol) in acetonitrile (50 mL), followed by
ammonium acetate (0.116 g, 1.5 mmol). The reaulting mixture was stirred at ambient temperature for 3 h (Scheme
1). Then the volatiles were removed under the reduced pressure and the residue was taken in ethyl acetate and
water mixture (50 mL, 1:1). The mixture was extracted with ethyl acetate (3×20 mL). Organic layer was collected,
washed with brine, dried over anhydrous MgSO4 and concentrated under reduced pressure. The oily residue was
purified by column chromatography (ethyl acetate/petroleum ether, 1:40) to give 3-bromo-4-hydroxycoumarin as
light yellow solid (3.266 g, 88%), which was used for the next step without characterization.
Synthesis of 3-bromo-2-oxo-2H-chromen-4-yltrifluoromethane-sulfonate11 After the solution of
o
3-bromo-4-hydroxycoumarin (0.964 g, 4.0 mmol) in dry dichloromethane (100 mL) was cooled to 0 C (ice bath)
in a hot-oven dried Schlenk test tube, triethylamine (0.7 mL, 5.10 mmol) was added and stirred for another 5 min.
Then triflic anhydride (2.6 mL, 15 mmol) was added slowly. After the reaction mixture was stirred at 0 °C for 6 h,
it was poured into water and extracted with dichloromethane (3×20 mL). Organic layer was collected, washed
(brine), dried (anhydrous Na2SO4) and concentrated under the reduced pressure. The oil residue was purified by
column chromatography (ethyl acetate/petroleum ether, 1:30) to give white solid (0.925 g, 62%).
Syntheses of 4-aryl-3-heteroaryl-2H-chromen-2-one derivatives (1a-1s, 3, 4, 6)17, 18 According a
typical procedure, a hot-oven dried Schlenk tube was charged with 3-bromo-4-trifloxycoumarin (1.0 mmol, 0.373
g), phenylboronic acid (1.0 mmol, 0.122 g), NaHCO3 (2.0 mmol, 0.168 g), Pd(PhCN)2Cl2(0.5 mol %) and CH3OH
(20 mL) under nitrogen atmosphere. The reaction mixture was stirred at 10 °C (water bath) for 4h. Then the
reaction mixture was poured into water (20 mL) and extracted with ethyl acetate (3×20 mL). The organic layer was
combined and volatiles were removed under reduced pressure. The crude product was purified on silica gel column
chromatography (ethyl acetate/petroleum ether, 1:60) and was used directly in the next step.
A mixture of 3-bromo-4-phenyl-2H-chromen-2-one (0.5 mmol, 0.151 g), furan-2-ylboronic acid (1 mmol, 0.112
g), Pd(PPh3)4 (0.5 mol %) and CsCO3 (1.5 mmol, 0.289 g) in 1,4-dioxane (20.0 mL) was stirred at 90 °C for a
period of time. After completion of the reaction as indicated by TLC, the mixture was cooled to room temperature
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and volatiles were removed under reduced pressure. The residue was purified by silica gel by column
chromatography (EtOAc/petroleum ether, 1:30) to give 1a in 50%. Analogously, 1b-1n, 1p-1s, 3, 4 were prepared
according to this methodology above described, with yields 50%~83%. (The reaction scheme is in SI-Scheme S2).
A cold diluted solution of BBr3 (2.01 g, 8 mmol) in dry chloroform was added to a solution of 3-(furan-2-yl)
-4-(4-methoxyphenyl)-2H-chromen-2-one (1m, 0.637 g, 2 mmol) in dry chloroform and stirred at 0 °C for 30 min.
The reaction mixture was refluxed for 12 h, then, cooled to room temperature. The excess of BBr3 was quenched
by the addition of MeOH (20 mL). The volatiles were removed under the reduced pressure and the residue was
column chromatographed (ethyl acetate/petroleum ether, 1:50 → 1:5) to give 1o (48%).19 (The reaction scheme is
in SI-Scheme S3).
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Synthesis of 3-(Furan-2-yl)-4-phenyl-2H-chromene (7).20 The NaBH4 (113 mg, 1.5 mmol) was
added to a solution of 3-(furan-2-yl)-4-phenyl-2H-chromen-2-one 1a (145 mg, 0.5 mmol) in EtOH (10 ml). The
mixture was stirred at 35 °C for 8 h under Ar, poured into the saturated ammonium chloride to quench the reaction.
The mixture was extracted with ethyl acetate (20 ml×3) and combined, the organic layer dried over (Mg2SO4),
concentrated under reduced pressure. The oily residue was purified by column chromatography (petroleum ether)
to give 7 (yield, 31 %).
4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2a). Yield: 64%, 46 mg; Yellow solid; m.p. 179.3-
180.1 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 7.28(d, J = 2.0 Hz, 1H), 7.36(dd, J = 6.7, 4.1 Hz, 1H), 7.42-7.55(m,
2H), 7.61(dd, J = 7.4, 4.1 Hz, 1H), 7.75(t, J = 7.5 Hz, 1H), 7.98(d, J =1.9 Hz, 1H), 8.20(t, J = 8.1 Hz, 1H), 8.38(d,
J = 8.1 Hz, 1H), 8.80(d, J = 8.7 Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.4, 151.5, 148.8, 146.9,
132.9, 131.5, 129.9, 129.7, 128.5, 128.4, 125.9, 125.5, 125.1, 124.5, 124.2, 118.8, 117.9, 108.9, 105.5. IR (KBr) ν
(cm-1) 3366, 3160, 2925, 2845, 1745, 1599, 1465, 1107, 1071. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C19H10O3Na 309.0522; Found 309.0533.
12-Methyl-4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2b). Yield: 67%, 50 mg; Yellow solid;
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m.p. 212.7- 214.1 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.63(s, 3H), 7.28(d, J = 1.9 Hz, 1H), 7.37(s, 1H),
7.45(dd, J = 8.8, 1.0 Hz, 1H), 7.51 (t, J = 3.4 Hz, 2H), 7.98(d, J = 1.3 Hz, 2H), 8.42(d, J = 8.1 Hz, 1H), 8.73(d, J =
8.8 Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.6, 151.6, 149.1, 146.7, 140.3, 133.0, 131.9, 129.9,
128.4, 128.4, 128.0, 124.7, 124.2, 123.9, 123.7, 118.9, 117.9, 108.4, 105.4, 21.9. IR (KBr) ν (cm-1) 2960, 2872,
1723, 1627, 1471, 1459, 1383, 1019, 759. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H12O3Na 323.0679;
Found 323.0691.
12-Ethyl-4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2c). Yield: 66%, 52 mg; Yellow solid;
m.p. 236.1-237.1 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 1.41(t, J = 7.6 Hz, 3H), 2.93(s, J = 7.6 Hz, 2H), 7.30(d, J
= 1.7 Hz, 1H), 7.37(s, 1H), 7.49 (t, J = 8.5 Hz, 3H), 7.99 (s, 2H), 8.43(d, J = 8.1 Hz, 1H), 8.75(d, J = 8.8 Hz, 1H).
13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.6, 151.5, 149.1, 146.7, 146.4, 132.9, 131.9, 129.9, 128.6, 128.4,
126.9, 124.8, 124.2, 123.9, 122.6, 118.9, 117.9, 108.3, 105.5, 29.2, 15.4. IR (KBr) ν (cm-1) 2943, 1723, 1625, 1470,
1075, 1354, 759. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C21H14O3Na 337.0835; Found 337.0852.
12-Fluoro-4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2d). Yield: 50%, 38 mg; Yellow solid;
m.p. 222.4-223.8 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 7.28(s, 1H), 7.42 (t, J = 7.8 Hz, 2H), 7.55(dd, J = 12.7,
7.5 Hz, 2H), 7.79-7.96(m, 1H), 8.03(s, 1H), 8.38(d, J = 8.1 Hz, 1H), 8.91(dd, J = 9.4, 5.5 Hz, 1H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 164.3(d,1J = 252.0 Hz), 158.3, 151.6, 149.4, 147.1, 133.6(d, 3J = 9.6 Hz), 133.3,
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131.6(d, 3J = 9.5 Hz), 130.3, 128.3, 124.8, 124.7, 124.4, 122.5, 118.6, 118.1, 115.6(d, 2J = 23.9 Hz), 109.1(d, 2J =
21.4 Hz), 105.6. IR (KBr) ν (cm-1) 3065, 2912, 1723, 1625, 1470, 1075, 1354, 759. HRMS(ESI-TOF) m/z: [M +
Na]+ Calcd for C19H9FO3Na 327.0428; Found 327.0425.
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12-Chloro-4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2e). Yield: 40%, 32 mg; Yellow solid;
m.p. 215.9-216.8 oC. H NMR(400 MHz, CDCl3) δ(ppm) 7.60(d, J = 2.3 Hz, 1H), 7.77-7.70(m, 1H), 7.88(dt, J =
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15.6, 4.6 Hz, 3H), 8.35(d, J = 1.9 Hz, 1H), 8.51 (d, J = 1.9 Hz, 1H), 8.67(d, J = 8.1 Hz, 1H), 9.12(d, J = 9.2 Hz,
1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.1, 151.6, 149.5, 147.3, 136.1, 133.0, 132.5, 130.4, 130.2, 128.2,
126.7, 124.5, 124.4, 123.9, 123.8, 118.5, 118.1, 109.1, 105.4. IR (KBr) ν (cm-1) 2933, 1753, 1625, 1520, 1474,
1355, 739. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H9ClO3Na 343.0132; Found 343.0132.
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12-Trifluoromethyl-4H-furo[2',3':3,4]naphtho[2,1-c]chromen-4-one (2f). Yield: 51%, 45 mg;
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Yellow solid; m.p. 247.9-248.6 C. H NMR(400 MHz, CDCl3) δ(ppm) 7.21-7.60(m, 3H), 7.71-8.09(m, 2H),
8.09(d, J = 4.8 Hz, 1H), 8.45(d, J = 8.0 Hz, 1H), 8.74(s, 1H), 9.03(d, J = 8.7 Hz, 1H). 13C{1H} NMR(101 MHz,
CDCl3) δ(ppm) 157.9, 151.6,149.4, 147.7, 132.7, 131.6, 130.9(d, J = 12.6 Hz), 130.8, 130.6, 129.7, 128.2, 127.2,
125.6, 124.6, 122.6, 122.0(d, J = 4.2 Hz), 121.6(d, J = 3.3 Hz), 118.3(d, J = 15.9 Hz), 110.4, 105.5. IR (KBr) ν
(cm-1) 3114, 2923, 2340, 1756, 1531, 1355, 1281, 759. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H9F3O3Na
377.0396; Found 377.0395.
1H-benzofuro[2',3':3,4]naphtho[2,1-c]chromen-1-one (2g). Yield: 68%, 57 mg; Yellow solid; m.p.
177.3-178.8 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 7.41(dd, J = 1.2, 6.8 Hz, 1H), 7.53(m, 4H), 7.66(dd, J = 0.8,
7.5 Hz, 1H), 7.86(dd, J = 7.8, 6.8 Hz, 2H), 8.34(d, J = 7.5 Hz, 1H), 8.42(d, J = 8.0 Hz, 1H), 8.66(d, J = 8.3 Hz,
1H), 8.87(d, J = 6.7Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.1, 156.9, 151.9, 151.2, 135.5, 132.7,
130.5, 130.3, 128.9, 128.9, 127.2, 125.7, 125.4, 124.3, 123.9, 123.4, 121.9, 119.5, 118.7, 118.0, 113.0, 108.8. IR
(KBr) ν (cm-1) 2939, 2840, 1745, 1599, 1464, 1106, 1071. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C23H12O3Na 359.0679; Found 359.0680.15
9-Methyl-1H-benzofuro[2',3':3,4]naphtho[2,1-c]chromen-1-one (2h). Yield: 69%, 60 mg; Yellow
solid; m.p. 249.2-250.1 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.63(s, 3H), 7.333-7.44(m, 2H), 7.50(dt, J = 19.9,
7.4 Hz, 4H), 7.82(d, J = 8.1 Hz, 1H), 8.25-8.31(m, 2H), 8.34(d, J = 8.1 Hz, 1H), 8.66(d, J = 8.8 Hz, 1H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 158.1, 156.8, 151.9, 151.4, 140.9, 135.3, 132.9, 130.3, 128.8, 128.6, 127.7, 126.9,
124.2, 123.8, 123.6, 123.5, 123.4, 121.9, 118.8, 118.7, 117.9, 112.9, 107.9, 22.2. IR (KBr) ν (cm-1) 2922, 2847,
1732, 1625, 1465, 1351, 1059. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C24H14O3Na 373.0835; Found
373.0836.
9-Methoxy-1H-benzofuro[2',3':3,4]naphtho[2,1-c]chromen-1-one (2i). Yield: 76%, 69 mg; Yellow
solid; m.p. 242.1-242.8 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 4.04(s, 3H), 7.17(dd, J = 9.5, 2.6 Hz, 1H), 7.37(d,
J = 8.1 Hz, 1H), 7.38-7.65(m, 4H), 7.76(dd, J = 24.6, 5.2 Hz, 2H), 8.13(d, J = 7.5 Hz, 1H), 8.28(d, J = 8.1 Hz, 1H),
8.64(d, J = 9.4 Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.9, 158.1, 156.7, 151.9, 151.8, 135.4, 134.7,
130.5, 130.3, 128.8, 126.8, 124.2, 123.8, 123.4, 121.4, 119.9, 118.6, 118.3, 117.9, 116.9, 112.9, 106.6, 103.9, 55.7.
IR (KBr) ν (cm-1) 2928, 2843, 1730, 1617, 1465, 1358, 1053. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C24H14O4Na 389.0784; Found 389.0788.
9-Fluoro-1H-benzofuro[2',3':3,4]naphtho[2,1-c]chromen-1-one (2j). Yield: 67%, 59 mg; Yellow
solid; m.p. 246.8-248.1 oC. 1H NMR(400 MHz, CDCl3 + d6-DMSO) δ(ppm) 7.27-7.41(m, 2H), 7.45- 7.77(m, 4H),
7.87(d, J = 8.1, 1H), 8.10-8.33(m, 2H), 8.35(d, J = 8.0 Hz, 1H), 8.90(dd, J = 9.4, 5.7 Hz, 1H). 13C{1H} NMR(101
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MHz, CDCl3) δ(ppm) 157.1, 156.1, 151.2, 151.1, 135.1, 133.6(d, J = 7.1 Hz), 131.4(d, 3J = 6.1 Hz), 130.3, 128.1,
125.4(d, 1J = 280.3 Hz), 123.7, 122.4, 121.7, 121.0, 118.3, 117.5(d, 2J = 37 Hz), 114.9(d, 2J = 26 Hz), 112.2, 108.2,
108.1, 107.5. IR (KBr) ν (cm-1) 2919, 2853, 2341, 1741, 1624, 1451, 1058. HRMS(ESI-TOF) m/z: [M + Na]+
Calcd for C23H11FO3Na 377.0584; Found 377.0590.
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4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2k). Yield: 68%, 51 mg; Yellow solid; m.p. 204.4-
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205.7 C. H NMR(400 MHz, CDCl3) δ(ppm) 7.30-7.41(m, 1H), 7.46-7.56(m, 2H), 7.62(d, J = 8.0 Hz, 1H),
7.67-7.91(m, 2H), 7.97(d, J = 5.5 Hz, 1H), 8.40(t, J = 7.3 Hz, 2H), 8.79(d, J = 8.6 Hz, 1H). 13C{1H} NMR(101
MHz, CDCl3) δ(ppm) 160.9, 151.2, 137.4, 134.2, 132.9, 132.8, 131.2, 129.9, 129.7, 128.3, 128.2, 126.3, 126.2,
124.8, 124.3, 121.1, 118.8, 117.9, 115.7. IR (KBr) ν (cm-1) 3106, 2832, 1708, 1604, 1446, 1165, 767, 727.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H10O2S Na 325.0294, Found 325.0300.
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12-Methyl-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2l). Yield: 73% (55 mg); Yellow solid;
m.p. 199.6-200.3 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.58(s, 3H), 7.26-7.38(m, 2H), 7.48(t, J = 5.0 Hz, 2H),
7.72(d, J = 5.5 Hz, 1H), 7.86(d, J = 5.5 Hz, 1H), 8.05(s, 1H), 8.29(d, J = 8.1 Hz, 1H), 8.53(d, J = 8.7 Hz, 1H).
13C{1H} NMR(101MHz, CDCl3) δ(ppm) 160.9, 151.1, 140.1, 136.8, 134.2, 132.8, 132.7, 130.7, 129.8, 128.1,
128.1, 127.9, 124.2, 124.2, 121.0, 118.8, 117.8, 114.9, 22.0. IR (KBr) ν (cm-1) 2916, 2354, 1700, 1621, 1471, 1169,
769, 719. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H12O2SNa 339.0450; Found 339.0457.
12-Methoxy-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2m). Yield: 74%, 61 mg; Yellow
solid; m.p. 143.1-144.5 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 4.03(s, 3H), 7.19(dd, J = 2.4, 2.6 Hz, 1H),
7.28-7.41(m, 1H), 7.38-7.59(m, 2H), 7.62(d, J = 2.5 Hz, 1H), 7.73(d, J = 5.4 Hz, 1H), 7.86(d, J = 5.5 Hz, 1H),
8.31(d, J = 8.1 Hz, 1H), 8.63(d, J = 9.4 Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.9, 160.5, 151.2,
136.4, 134.9, 134.8, 132.9, 130.5, 129.9, 129.9, 128.2, 124.3, 121.0, 120.9, 118.8, 117.9, 117.1, 113.8, 104.7, 55.68.
IR (KBr) ν (cm-1) 2932, 2836, 1699, 1614, 1483, 1166, 768, 722. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C20H12O3SNa 355.0399; Found 355.0405.
11-Methoxy-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2n). Yield: 51%, 42 mg; Yellow
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solid; m.p. 140.1-141.9 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.60(s, 3H), 7.41-7.49(m, 2H), 7.55(dd, J = 11.1,
8.7 Hz, 2H), 7.89(d, J = 5.5 Hz, 1H), 8.07(d, J = 5.5 Hz, 1H), 8.10(s, 1H), 8.74(d, J = 8.0 Hz, 1H), 9.72(d, J = 8.9
Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.6, 159.9, 157.5, 154.6, 152.7, 152.6, 136.6, 132.2, 130.3,
127.8, 124.9, 120.4, 120.4, 117.2, 116.9, 114.9, 113.9, 112.7, 55.6. IR (KBr) ν (cm-1) 3082, 2837, 1719, 1589, 1451,
1169, 997, 754. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H12O3SNa 355.0399; Found 355.0407.
12-Hydroxy-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2o). Yield: 39%, 31 mg; Yellow
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solid; m.p. 146.3-147.1 C. H NMR(400 MHz, d6-DMSO) δ(ppm) 7.26-7.30(m, 1H), 7.53(d, J = 5.1 Hz, 2H),
7.59(d, J = 1.7 Hz, 1H), 7.90(s, 2H), 8.20(d, J = 2.0 Hz, 1H), 8.25(d, J = 8.0 Hz, 1H), 8.62(d, J = 9.0 Hz, 1H),
10.73(s, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 172.9, 163.4, 156.7, 151.7, 146.8, 145.9, 130.3, 129.2,
127.4, 125.8, 124.0, 123.7, 120.9, 119.3, 115.2, 114.7, 108.1, 105.6, 102.4. IR (KBr) ν (cm-1) 3079, 2989, 2821,
1721, 1624, 1483, 1174, 748, 712. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H10O2SNa 341.0243; Found
341.0244.
12-Fluoro-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2p). Yield: 65%, 52 mg; Yellow solid;
m.p. 182.1-183.4 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 7.33-7.42(m, 2H), 7.53(dt, J = 15.1, 7.5 Hz, 2H), 7.79(d,
J = 5.5 Hz, 1H), 7.86(d, J = 5.4 Hz, 1H), 7.95(dd, J = 9.7, 2.5 Hz, 1H), 8.30(d, J = 8.1 Hz, 1H), 8.79(dd, J = 9.4,
5.6 Hz, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 162.9(d, 1J = 254.5 Hz), 160.7, 151.2, 136.6, 135.2,
134.6(d, 3J = 9.1 Hz), 132.8, 131.4, 131.1(d, 3J = 9.1 Hz), 130.2, 128.0, 124.5, 123.1, 121.1, 118.5, 118.1, 115.7(d,
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2J = 24.2 Hz), 115.2, 109.4(d, J = 21.2 Hz). IR (KBr) ν (cm-1) 3090, 2926, 2853, 1706, 1603, 1328, 1184, 755,
715. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for for C19H9FO2SNa 343.0199; Found 343.0208.
2-Methyl-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2q). Yield: 70%, 55 mg; Yellow solid;
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m.p. 195.1.4-196.5 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.67(s, 3H), 7.28-7.41(m, 1H), 7.34-7.62(m, 4H),
7.64(t, J = 7.5 Hz, 1H), 8.18(d, J = 8.2 Hz, 1H), 8.31(d, J = 8.1 Hz, 1H), 8.67(d, J = 8.6 Hz, 1H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 160.9, 150.9, 145.8, 137.7, 133.4, 132.1, 131.5, 129.5, 129.2, 128.1, 126.2, 125.9,
124.7, 124.2, 119.1, 118.9, 117.8, 115.4, 16.1. IR (KBr) ν (cm-1) 2993, 2842, 2373, 1695, 1603, 1457, 1174, 1366.
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HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H12O2SNa 339.0456; Found 339.0466.
2, 12-Dimethyl-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2r). Yield: 73%, 60 mg; Yellow
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solid; m.p. 214.9-216.2 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.60(s, 3H), 2.70(s, 3H), 7.38(t, J = 8.7 Hz, 2H),
7.49(d, J = 2.6 Hz, 2H), 7.57(s, 1H), 8.04(s, 1H), 8.38(d, J = 8.1 Hz, 1H), 8.63(d, J = 8.7 Hz, 1H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 161.1, 151.1, 145.6, 139.9, 137.6, 133.7, 132.6, 131.9, 129.5, 128.1, 128.1, 128.0,
124.5, 124.3, 124.2, 119.2, 119.2, 117.9, 114.9, 22.1, 16.2. IR (KBr) ν (cm-1) 2923, 2841, 1712, 1620, 1459, 1368,
1119. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C21H14O2SNa 353.0607; Found 353.0619.
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12-Fluoro-2-methyl-4H-thieno[2',3':3,4]naphtho[2,1-c]chromen-4-one (2s). Yield: 52%, 43 mg;
Yellow solid; m.p. 214.0-215.3 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.72(s, 3H), 7.28-7.44(m, 2H),
7.41-7.60(m, 3H), 7.87(dd, J = 9.9, 2.6 Hz, 1H), 8.33(d, J = 8.1 Hz, 1H), 8.80(dd, J = 9.4, 5.6 Hz, 1H). 13C{1H}
(101 MHz, CDCl3) δ(ppm) 162.8(d, 1J = 253.5 Hz), 160.8, 151.1, 146.3, 137.2(d, 4J = 4.6 Hz), 134.4, 134.0(d, 3J =
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9.3 Hz), 131.6, 130.9(d, 1J = 9.1 Hz), 129.9, 127.9, 124.4, 123.2, 119.2, 118.8, 118.1, 115.5(d, J = 23.9 Hz), 115.1,
109.3(d, 2J = 21.8 Hz), 16.2. IR (KBr) ν (cm-1) 2914, 2839, 1697, 1503, 1456, 1128. HRMS(ESI-TOF) m/z: [M +
Na]+ Calcd for C20H11FO2S Na 357.0356; Found 357.0369.
3-(Furan-2-yl)-4-phenyl-2H-chromen-2-one (1a). Yield: 50%, 144.2 mg; Yellow solid; m.p. 144.1.3-
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145.3.1 C. H NMR(400 MHz, CDCl3) δ(ppm) 6.27(m, 1H), 6.79(d, J = 3.2 Hz, 1H), 7.09 (t, J = 7.3 Hz, 3H),
7.15-7.20(m, 2H), 7.34(d, J = 8.3 Hz, 1H), 7.40(d, J = 4.6 Hz, 3H), 7.43-7.47(m, 1H). 13C{1H} NMR(101 MHz,
CDCl3) δ(ppm) 159.4, 152.6, 149.6, 147.2, 142.9, 135.6, 131.6, 128.7, 128.5, 128.4, 127.9, 124.4, 120.8, 116.7,
116.4, 114.6, 111.2. IR (KBr) ν (cm-1) 3209, 2340, 1727, 1592, 1447, 992, 752, 697. HRMS(ESI-TOF) m/z: [M +
Na]+ Calcd for C19H12O3Na 311.0679; Found 311.0686.
3-(Furan-2-yl)-4-(p-tolyl)-2H-chromen-2-one (1b). Yield: 67%, 202.6 mg; Yellow solid. m.p.
133.3-134.1 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.41(s, 3H), 6.30(dd, J = 3.3, 1.6 Hz, 1H), 6.77(d, J = 3.4 Hz,
1H), 7.10(t, J = 8.0 Hz, 3H), 7.14-7.20(m, 2H), 7.23(d, J = 7.9 Hz, 2H), 7.35(d, J = 8.2 Hz, 1H), 7.44-7.48(m, 1H).
13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 159.3, 152.5, 150.1, 147.2, 142.8, 138.2, 132.4, 131.4, 129.0, 128.5,
127.9, 124.2, 120.8, 116.5, 116.3, 114.3, 111.0, 21.4. IR (KBr) ν (cm-1) 3019, 2320, 1716, 1593, 1471, 1485, 989,
746. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H14O3Na 325.0835; Found 325.0842.
4-(4-Ethylphenyl)-3-(furan-2-yl)-2H-chromen-2-one (1c). Yield: 70%, 221.4 mg; Yellow solid; m.p.
110.6-111.5 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 1.18(t, J = 7.6 Hz, 3H), 2.61(q, J = 7.6 Hz, 2H), 6.18-6.23(m,
1H), 6.65(d, J = 3.4 Hz, 1H), 7.05 (dd, J = 11.6, 8.8 Hz, 5H), 7.15(d, J = 8.1 Hz, 2H), 7.26(d, J = 8.2 Hz, 1H),
7.35-7.40(m, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 159.5, 152.6, 150.2, 147.3, 144.7, 142.9, 132.7, 131.5,
128.7, 128.0, 127.9, 124.3, 120.9, 116.6, 116.5, 114.3, 111.1, 28.8, 15.5. IR (KBr) ν (cm-1) 2977, 2367, 1703, 1590,
1480, 1375, 767, 725. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for Na 339.0992; Found 339.0996.
4-(4-Fluorophenyl)-3-(furan-2-yl)-2H-chromen-2-one (1d). Yield: 57% (174.6 mg); Yellow solid;
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m.p. 118.3-119.5 C. H NMR(400 MHz, CDCl3) δ(ppm) 6.36(dd, J = 1.8, 1.9 Hz, 1H), 6.93(d, J = 3.4 Hz, 1H),
7.12-7.18(m, 5H), 7.20-7.24(m, 2H), 7.39(d, J = 8.1 Hz, 1H), 7.49-7.59(m, 1H). 13C{1H} NMR(101 MHz, CDCl3)
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δ(ppm) 164.0, 161.4(d, J = 243 Hz), 152.5, 148.3, 147.1, 143.1, 131.7, 131.6(d, J = 3.0 Hz), 130.6(d, J = 8.2
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Hz), 127.6, 124.5, 120.8, 116.8, 115.7(d, J = 22.2 Hz), 114.9, 111.3. IR (KBr) ν (cm-1) 3071, 2359, 1722, 1601,
1506, 1217, 1017, 739. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H11FO3Na 329.0584; Found 329.0590.
4-(4-Chlorophenyl)-3-(furan-2-yl)-2H-chromen-2-one (1e). Yield: 50%, 161.4 mg; Yellow solid; m.p.
143.6-144.7 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 6.35(dd, J = 3.4, 1.5 Hz, 1H), 6.97(d, J = 3.4 Hz, 1H), 7.11(s,
1H), 7.13-7.19(m, 4H), 7.37(d, J = 8.0 Hz, 1H), 7.42-7.45(m, 2H), 7.48-7.52(m, 1H). 13C{1H} NMR(101 MHz,
CDCl3) δ(ppm) 158.9, 152.4, 147.8, 146.9, 143.2, 134.5, 134.1, 131.7, 130.2, 128.8, 127.5, 124.4, 120.5, 116.7,
116.5, 115.0, 111.3. IR (KBr) ν (cm-1) 2920, 2371, 1703, 1592, 1479, 924, 749, 731. HRMS(ESI-TOF) m/z: [M +
Na]+ Calcd for C19H11ClO3Na 345.0289; Found 345.0286.
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3-(Furan-2-yl)-4-(4-(trifluoromethyl)phenyl)-2H-chromen-2-one (1f). Yield: 53%, 188.8 mg;
Yellow solid; m.p. 157.2-158.8 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 6.37 (dd, J = 3.2, 1.5 Hz, 1H), 7.03 (d, J =
8.0 Hz, 1H), 7.12-7.04 (m, 2H), 7.18 (t, J = 7.7 Hz, 1H), 7.41(t, J = 7.3 Hz, 3H), 7.53 (t, J = 7.6 Hz, 1H), 7.74 (d, J
= 8.1 Hz, 2H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 158.9, 152.4, 146.8, 143.4, 139.7, 131.8, 130.9, 130.6,
129.3, 127.4, 125.5(d, J = 3.5 Hz), 125.5(d, J = 3.0 Hz), 124.6, 122.8, 120.4, 116.9, 116.5, 115.5, 111.5. IR (KBr)
ν (cm-1) 2936, 2367, 1705, 1598, 1493, 1322, 1109, 854, 766. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C20H11F3O3Na 379.0552; Found 379.0553.
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3-(Benzofuran-2-yl)-4-phenyl-2H-chromen-2-one (1g)6. Yield: 72%, 243.6 mg. Yellow solid. m.p.
177.3- 178.8 ℃. 1H NMR(400 MHz, CDCl3) δ(ppm) 6.00-7.02(m, 1H), 7.13-7.18(m, 2H), 7.21(t, J = 4.6 Hz, 2H),
7.29(dd, J = 6.5, 3.0 Hz, 2H), 7.35(s, 1H), 7.42-7.47(m, 4H), 7.51-7.57(m, 2H). 13C{1H} NMR(101 MHz, CDCl3)
δ(ppm) 159.2, 154.5, 152.8, 151.6, 149.3, 135.6, 132.1, 128.7, 128.6, 128.4, 128.3, 128.2, 125.0, 124.5, 122.9,
121.6, 120.8, 116.8, 116.3, 111.1, 110.9. IR (KBr) ν (cm-1) 2929, 2370, 1722, 1603, 1522, 1443, 1112, 988, 794.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C23H14O3Na 361.0835; Found 361.0833.
3-(Benzofuran-2-yl)-4-(p-tolyl)-2H-chromen-2-one (1h). Yield: 79%, 278.4 mg; Yellow solid; m.p.
174.4-176.5 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.43(s, 3H), 7.06(d, J = 7.8 Hz, 1H), 7.15(m, 4H),
7.20-7.28(m, 5H), 7.42(d, J = 8.2 Hz, 1H), 7.50-7.56(m, 2H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 159.4,
154.6, 152.9, 152.3, 149.4, 138.6, 132.4, 132.1, 129.1, 128.6, 128.4, 128.3, 124.9, 124.5, 122.9, 121.6, 120.9,
116.8, 116.4, 111.1, 110.8, 21.5. IR (KBr) ν (cm-1) 2920, 2360, 1716, 1593, 1504, 1115, 996, 813, 741.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C24H16O3Na 375.0992; Found 375.0995.
3-(Benzofuran-2-yl)-4-(4-methoxyphenyl)-2H-chromen-2-one (1i). Yield: 80%, 294.7 mg; Yellow
solid; m.p. 155.3-156.5 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 3.86(s, 3H), 6.97(d, J = 8.7 Hz, 2H), 7.08-7.12(m,
1H), 7.12-7.19(m, 2H), 7.18-7.21(m, 2H), 7.23(d, J = 5.2 Hz, 2H), 7.31(dd, J = 8.1, 1.3 Hz, 1H), 7.42(d, J = 8.2
Hz, 1H), 7.51-7.57(m, 2H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 159.6, 159.0, 154.2, 152.5, 151.7, 149.1,
131.7, 129.7, 127.9, 127.9, 127.1, 124.5, 124.1, 122.5, 121.2, 120.5, 116.4, 116.1, 113.6, 110.7, 110.4, 55.1. IR
(KBr) ν (cm-1) 2850, 2354, 1718, 1607, 1503, 1246, 1028, 818, 744. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C24H16O4Na 391.0941; Found 391.0936.
3-(Benzofuran-2-yl)-4-(4-fluorophenyl)-2H-chromen-2-one (1j). Yield: 71%, 253.0 mg; Yellow solid;
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m.p. 151.5-153.4 C. H NMR(400 MHz, CDCl3) δ(ppm) 6.99(d, J = 8.0 Hz, 1H), 7.11(dd, J = 6.8, 2.0 Hz, 2H),
7.14(dd, J = 5.4, 1.8 Hz, 2H), 7.17(dd, J = 5.5, 1.5 Hz, 2H), 7.23(dd, J = 6.0, 2.6 Hz, 2H), 7.36-7.40(m, 2H),
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7.48-7.54(m, 2H); 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 162.9(d, J = 250.5 Hz), 159.0, 154.5, 152.7, 150.3,
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149.0, 132.2, 131.5(d, J = 4.02 Hz), 130.6(d, J = 8.1 Hz), 128.2, 127.9, 125.2, 124.6, 123.1, 121.7, 120.72,
116.7(d, 2J = 29.2 Hz), 115.6(d, 2J = 22.2 Hz), 111.4, 110.9. IR (KBr) ν (cm-1) 3168, 2357, 1727, 1600, 1498, 1296,
1219, 1110, 750. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C23H13FO3Na 379.0741; Found 379.0741.
4-Phenyl-3-(thiophen-2-yl)-2H-chromen-2-one (1k). Yield: 78%, 240.4 mg; Yellow solid; m.p.
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164.2-165.5 C. H NMR(400 MHz, CDCl3) 6.84(dd, J = 4.9, 3.9 Hz, 1H), 6.95-6.97(m, 1H), 7.25-7.12(m, 5H),
7.41(d, J = 8.3 Hz, 1H), 7.47-7.44(m, 3H), 7.54-7.49(m, 1H). 13C{1H} NMR (101MHz, CDCl3) δ(ppm) 160.6,
152.7, 150.6, 135.2, 134.6, 131.6, 130.9, 129.3, 129.0, 128.0, 127.9, 126.2, 124.4, 120.9, 120.3, 116.7. IR (KBr) ν
(cm-1) 2926, 2349, 1707, 1600, 1450, 759, 704. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H12O2SNa
327.0450; Found 327.0450.
3-(Thiophen-2-yl)-4-(p-tolyl)-2H-chromen-2-one (1l). Yield: 83%, 264.2 mg; Yellow solid; m.p.
166.0-167.9 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.35(s, 3H), 7.03(d, J = 3.0 Hz, 1H), 7.09-7.05 (m, 1H), 7.12
(q, J = 8.2 Hz, 4H), 7.29(d, J = 8.3 Hz, 1H), 7.41(d, J = 4.7 Hz, 1H), 7.45(d, J = 8.1 Hz, 1H), 7.62-7.54(m, 2H).
13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.6, 152.7, 150.8, 139.0, 134.8, 132.2, 131.5, 130.8, 129.7, 129.2,
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128.3, 128.1, 127.8, 126.2, 124.3, 121.0, 116.7, 21.6. IR (KBr) ν (cm-1) 1707, 1560, 1504, 1241, 1025, 748, 703.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H14O2SNa 341.0607; Found 341.0606.
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4-(4-Methoxyphenyl)-3-(thiophen-2-yl)-2H-chromen-2-one (1m). Yield: 80%, 267.5 mg; Yellow
solid; m.p. 159.2-161.4 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 3.87(s, 3H), 6.87(dd, J = 5.0, 3.9 Hz, 1H), 6.98(d,
J = 8.7 Hz, 2H), 7.02-7.06(m, 1H), 7.15(s, 1H), 7.17(s, 1H), 7.18-7.24(m, 2H), 7.26-7.27 (m, 1H), 7.41(d, J = 8.2
Hz, 1H), 7.52(m, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.6, 160.2, 152.7, 150.5, 134.9, 131.5, 130.8,
130.7, 128.0, 127.8, 127.2, 126.2, 124.3, 121.1, 120.4, 116.7, 114.5, 55.5. IR (KBr) ν (cm-1) 2841, 2546, 1709,
1564, 1503, 1246, 758, 702. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H14O3SNa 357.0556; Found
357.0554.
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4-(3-Methoxyphenyl)-3-(thiophen-2-yl)-2H-chromen-2-one (1n). Yield: 70%, 254.1 mg; Yellow solid;
m.p. 129.8-131.9 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 2.31(s, 3H), 6.99(d, J = 3.1 Hz, 1H), 7.02(d, J = 4.9 Hz,
1H), 7.09(q, J = 8.2 Hz, 4H), 7.24(s, 1H), 7.36-7.39(m, 1H), 7.42(d, J = 8.1 Hz, 1H), 7.56(m, 2H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 160.6, 159.9, 157.5, 154.6, 152.7, 152.6, 136.6, 132.2, 130.3, 127.8, 124.9, 120.4,
120.4, 117.2, 116.9, 114.9, 113.9, 112.7, 55.6. IR (KBr) ν (cm-1) 3079, 2829, 1716, 1588, 1451, 1031, 767, 710.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H14O3SNa 357.0556; Found 357.0555.
4-(4-Hydroxyphenyl)-3-(thiophen-2-yl)-2H-chromen-2-one (1o). Yield: 48%, 153.7 mg; Yellow solid;
m.p. 180.0-181.4 oC. 1H NMR(400 MHz, CDCl3) δ(ppm) 6.83(d, J = 8.5 Hz, 2H), 6.89(t, J = 4.4 Hz, 1H), 6.94(d,
J = 3.4 Hz, 1H), 7.05(d, J = 8.5 Hz, 2H), 7.14(d, J = 7.9 Hz, 1H), 7.27(t, J = 7.8, 7.5 Hz, 1H), 7.47(t, J = 4.6, 7.8
Hz, 2H), 7.61(t, J = 7.8, 7.5 Hz, 1H), 9.83(s, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 159.8, 158.0, 152.1,
150.9, 134.9, 131.9, 130.6, 130.5, 128.2, 127.9, 126.2, 125.1, 124.7, 120.8, 119.5, 116.4, 115.8. IR (KBr) ν (cm-1)
3091, 2927, 2789, 1729, 1604, 1543, 1266, 768, 701. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H12O3SNa
343.0399; Found 343.0397.
4-(4-Fluorophenyl)-3-(thiophen-2-yl)-2H-chromen-2-one (1p). Yield: 60%, 193.4 mg; Yellow solid;
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m.p. 169.5-171.0 C. H NMR(400 MHz, CDCl3) δ(ppm) 6.36(dd, J = 3.3, 1.9 Hz, 1H), 6.94 (d, J = 3.4 Hz, 1H),
7.25-7.20(m, 2H), 7.19-7.11(m, 5H), 7.40(d, J = 8.1 Hz, 1H), 7.54-7.49(m, 1H). 13C{1H} NMR(101 MHz, CDCl3)
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δ (ppm) 162.8(d, 1J = 249.5 Hz), 159.2, 152.5, 148.3, 147.1, 143.1, 131.7, 131.6(d, J = 3.6 Hz), 130.7(d, 3J = 8.2
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Hz), 127.6, 124.5, 120.8, 116.8, 115.7(d, J = 21.9 Hz), 114.9, 111.3. IR (KBr) ν (cm-1) 3071, 2922, 2369, 1705,
1594, 1454, 1322, 756. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H11FO2SNa 345.0356; Found 345.0355.
3-(5-Methylthiophen-2-yl)-4-phenyl-2H-chromen-2-one (1q). Yield: 79%, 232.4 mg; Yellow solid;
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m.p. 159.5.4-161.5 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.37(s, 3H), 6.47(d, J = 3.1 Hz, 1H), 6.69 (d, J = 3.6
Hz, 1H), 7.12(dt, J = 8.0, 7.3 Hz, 2H), 7.23(dd, J = 6.6, 3.0 Hz, 2H), 7.38(d, J = 8.0 Hz, 1H), 7.50-7.44(m, 4H).
13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 160.7, 152.5, 149.5, 142.7, 135.4, 132.2, 131.3, 131.2, 129.3, 129.1,
128.9, 127.8, 124.7, 124.3, 121.0, 120.5, 116.6, 15.2. IR (KBr) ν (cm-1) 3061, 2911, 1709, 1596, 1452, 755, 700.
HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C20H14O2SNa 341.0607; Found 341.0607.
3-(5-Methylthiophen-2-yl)-4-(p-tolyl)-2H-chromen-2-one (1r). Yield: 74%, 245.9 mg; Yellow solid;
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m.p. 136.9-137.8 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.37(s, 3H), 2.43(s, 3H), 6.46-6.50(m, 1H), 6.71(d, J =
3.7 Hz, 1H), 7.09-7.15(m, 4H), 7.26(d, J = 7.9 Hz, 2H), 7.37(d, J = 8.2 Hz, 1H), 7.45-7.49(m, 1H). 13C{1H}
NMR(101 MHz, CDCl3) δ(ppm) 160.8, 152.5, 149.7, 142.5, 138.8, 132.4, 132.3, 131.2, 131.1, 129.7, 129.1, 127.9,
124.7, 124.2, 121.2, 120.4, 116.6, 21.6, 15.2. IR (KBr) ν (cm-1) 2929, 2853, 1705, 1594, 1454, 1322, 756. HRMS
(ESI-TOF) m/z: [M + Na]+ Calcd for C21H16O2SNa 355.0763; Found 355.0764.
4-(4-Fluorophenyl)-3-(5-methylthiophen-2-yl)-2H-chromen-2-one (1s). Yield: 51%, 171.6 mg;
o
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Yellow solid; m.p. 150.2-151.6 C. H NMR(400 MHz, CDCl3) δ(ppm) 2.38(s, 3H), 6.51(d, J = 3.1 Hz, 1H),
6.75(d, J = 3.6 Hz, 1H), 7.09(d, J = 8.0 Hz, 1H), 7.14-7.19(m, 3H), 7.23(dd, J = 8.4, 5.6 Hz, 2H), 7.39(d, J = 8.2
Hz, 1H), 7.48-7.52(m, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 163.1(d, 1J = 249.5 Hz), 160.5, 152.5, 148.5,
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142.9, 132.1, 131.4, 131.3, 131.3, 131.2, 130.4(d, J = 8.1 Hz), 127.6, 124.8, 124.4, 120.9(d, J = 7.5 Hz), 116.7,
116.3(d, J = 22.2 Hz), 15.2. IR (KBr) ν (cm-1) 3074, 2909, 1703, 1598, 1503, 1211, 801, 755. HRMS(ESI-TOF)
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m/z: [M + Na]+ Calcd for C20H13FO2SNa 359.0512; Found 359.0512.
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3,4-Diphenyl-2H-chromen-2-one (3). Yield: 72%, 214.8 mg; white solid; m.p. 132.2-133.6 C. H NMR
(400 MHz, CDCl3) δ(ppm) 9.07-9.13(m, 4H), 9.13-9.21(m, 5H), 9.28(dd, J = 4.9, 1.5 Hz, 3H), 9.41(d, J = 8.1 Hz,
1H), 9.49-9.53(m, 1H). 13C{1H} NMR(101 MHz, CDCl3) δ(ppm) 161.4, 153.4, 151.7, 134.6, 134.0, 131.6, 130.7,
129.5, 128.5, 128.4, 127.9, 127.9, 127.8, 124.3, 120.7, 116.9. IR (KBr) ν (cm-1) 3085, 2354, 1698, 1606, 1552,
1211, 996, 743. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C21H14O2Na 321.0886; Found 321.0891.
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4-(Furan-2-yl)-3-phenyl-2H-chromen-2-one (4). Yield: 41%, 175.9 mg; Yellow solid. m.p. 214.5-215.7
oC. H NMR (400 MHz, CDCl3) δ (ppm) 6.16 (d, J = 3.4 Hz, 1H), 6.37 (dd, J = 3.3, 1.9 Hz, 1H), 7.18-7.23 (m,
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2H), 7.25 (dd, J = 5.4, 4.2 Hz, 1H), 7.30 (t, 3H), 7.40 (d, J = 8.0 Hz, 1H), 7.46 (d, J = 1.3 Hz, 1H), 7.52-7.57 (m,
1H), 7.71 (dd, J = 8.1, 1.0 Hz, 1H). 13C{1H} NMR (101MHz, CDCl3) δ (ppm) 161.2, 153.4, 147.2, 143.8, 140.2,
134.7, 131.7, 129.9, 128.2, 128.2, 127.8, 127.5, 124.5, 117.1, 114.9, 111.5. IR (KBr), ν (cm-1) 3081, 2362, 1691,
1595, 1446, 977, 762, 698. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for C19H12O3Na 311.0679; Found 311.0678.
o
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3,4-di(furan-2-yl)-2H-chromen-2-one (6). Yield: 56%, 155.8 mg; Yellow solid. m.p. 114.7-115.4 C. H
NMR (400 MHz, CDCl3) δ (ppm) 7.64 (dd, J = 7.8, 1.1 Hz, 1H), 7.58 (d, J = 1.4 Hz, 1H), 7.54 –7.49 (m, 1H), 7.36
(d, J = 8.1 Hz, 1H), 7.30 (d, J = 1.3 Hz, 1H), 7.25 (t, J = 7.3 Hz, 1H), 6.99 (d, J = 3.4 Hz, 1H), 6.57 (dd, J = 3.3,
1.6 Hz, 1H), 6.47–6.44 (m, 2H). 13C{1H} NMR (101MHz, CDCl3) δ (ppm) 159.2, 152.6, 147.0, 146.9, 143.9,
143.5, 137.9, 131.7, 127.3, 124.6, 119.4, 117.2, 116.8, 114.7, 113.3, 111.6, 111.6. IR (KBr), ν (cm-1) 3054, 1678,
1591, 1428, 959, 769, 691. Anal. calcd. for C17H17O4 (%): C, 73.31, H, 3.62, O, 23.00; found C, 73.22; H, 3.54, O,
23.09.
o
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3-(Furan-2-yl)-4-phenyl-2H-chromene (7). Yield: 36%, 85.6 mg; White solid; m.p. 89.1-89.9 C. H
NMR(400 MHz, CDCl3) δ(ppm) 5.24(d, J = 3.3 Hz, 1H), 6.04(m, 1H), 6.74 (d, J = 7.8 Hz, 1H), 6.85(m, 1H),
7.26(s, 2H), 7.03(d, J = 4.1 Hz, 2H), 7.23(d, J = 7.3 Hz, 2H), 7.42(m, 4H). 13C{1H} NMR(101 MHz, CDCl3)
δ(ppm) 150.6, 150.3, 141.4, 137.5, 132.1, 129.1, 128.6, 127.9, 126.7, 124.0, 121.8, 118.4, 117.2, 111.3, 110.2, 90.3,
77.4. IR (KBr) ν (cm-1) 3048, 2903, 1656, 1585, 1446, 967, 742, 658. HRMS(ESI-TOF) m/z: [M + Na]+ Calcd for
C19H14O2Na 297.0886; Found 297.0888.
ASSOCIATED CONTENT
AUTHOR INFORMATION
Corresponding Author
* E-mail: zhangzt@snnu.edu.cn
Present Address
§Department of Molecular Medicine, Beckman Research Institute of city of Hope, Duarte, CA
91010
ORCID
Juan Shi: 0000-0003-3025-6456
Yang Kang: 0000-0003-0856-1008
Tao Wang: 0000-0002-1494-5297
Yong Liang: 0000-0002-7225-7062
Zunting Zhang: 0000-0003-0806-2452
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Notes
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The authors declare no competing financial interest.
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ACKNOWLEDGMENTS
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We are grateful for financial support by the National Natural Science Foundation of China (Nos.
21672132 and 21502110) and Key Scientific Research Project of Natural Science Foundation of
Education Department of Shaanxi Provincial Goverrnment(No.18JS024).
Supporting Information
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The Supporting Information is available free of charge on the ACS Publications website.
X-ray parameters and structures of 2l.
Determination of fluorescence quantum yield for 2a-2s and 1a.
H2 detection for the photochemical dehydrocyclization of 2l by GC.
NMR spectra and MS spectra of compounds 1a-1s, 2a-2s, 3, 4, 6, 7. Fluorescence spectra of
2a-2s and 1a.
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