A facile approach for the synthesis of novel 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones by microwave enhanced Suzuki-Miyaura coupling using bidentate chromen-4-one-based Pd(II)-dIImine complex as catalyst

Article abstract of DOI:10.1039/c5ra15274g

A facile access to diversely substituted 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones using the microwave assisted phosphine-free Suzuki coupling of bromo flavones with boronic acids using a chromen-4-one-containing Pd(ii)-diimine

Full text of DOI:10.1039/c5ra15274g

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A facile approach for the synthesis of novel 1-oxa- and 1-aza-
flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones by
microwave enhanced Suzuki-Miyaura coupling using bidentate
chromen-4-one-based Pd(II)–diimine complex as catalyst
Sumit Kumar* and Naseem Ahmed*
Received 00th January 20xx,
Accepted 00th January 20xx
A facile access to diversely substituted 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones using the
microwave assisted phosphine-free Suzuki coupling of bromo flavones with boronic acids using chromen-4-one-containing
Pd(II)–diimine complex (C) as catalyst under aerobic condition is reported. A small amount of the catalyst (0.3 mol%) was
found to be highly effective for coupling to form the products in very high yields in 18-20 min under mild reaction
conditions. This catalytic system is compatible with a broad spectrum of olefinic or aryl bromide and aryl- or heteroaryl-
boronic acids. After screening various catalytic conditions, it was found that Pd complex of bidentate Schiff base ligand was
able to efficiently catalyze these reactions with yields up to 95%. The effect of solvent, base and catalyst loading on the
coupling reaction is also described.
DOI: 10.1039/x0xx00000x
www.rsc.org/
8
9
10
11
diaminos, amide, amines, oxime-based palladacycles, Cu-salen
Introduction
12
complex of tetradentate Schiff base ligands in water, N,O-
ligands, silica supported palladium–phosphine complex, tripodal
imidazolium salts, Pd nanoparticles immobilized by click ionic
copolymers in water, N-butyl pyridinium salts/water systems,
Metformin and Pd nanoparticles supported on silica diphenyl
phosphinite (SDPP) etc. as efficient catalysts.
The palladium-catalyzed Suzuki–Miyaura cross-coupling reaction of
aryl halides with aryl boronic acids has been considered as one of
the most powerful, convenient, and popular synthetic approaches
for preparation of carbon–carbon bond and biaryl compounds in
modern organic synthesis which are important structural scaffolds
in various natural products, polymers, agrochemicals, and
1
3
14
1
5
16
17
1
8
1
9
1
Among the plethora of N-based ligands, Schiff bases are unique
class of ligand which are well known as chelating multidentate
ligands in coordination chemistry as well as in catalysis because of
their simple and convenient synthetic route with economical and
commercially available starting material and high stability under a
pharmaceutical units. The most common reaction protocol for the
coupling is utilizing organic solvents, an inorganic base, a palladium
catalyst, and a ligand that coordinates to the palladium metal to
stabilize the complex. Amongst all factors, the ligand plays a critical
role in the successful accomplishment of the coupling reaction,
because the catalyst activity and selectivity depend on the
electronic and steric properties of the ligand coordinated to the Pd
metal. Usually catalytic system for these reactions composed of
Pd(0) or Pd(II) derivatives associated with appropriate ligands and
the efficiency of catalytic system is achieved by changing the ligand
20
wide range of redox conditions. Moreover, the steric and
electronic properties of Schiff bases can be easily manipulated by
appropriately selecting the precursor. These types of Schiff base
complexes with many active metals display excellent performance
2
1
as catalyst in palladium-catalyzed Suzuki reactions.
2
Nowadays, microwave irradiation has been extensively utilized in
organic transformations and its advantages over conventional
heating lay in the reduction in reaction time from hours to
environment around palladium center. In the conventional Suzuki–
Miyaura reactions, the electron-rich phosphine ligands are generally
3
employed to improve the catalytic performance. Since phosphine
2
2
4
minutes. Moreover, microwave heating is generally able to
increase yields, reduce side reactions, and improve
ligands are expensive, toxic and usually water- and air-sensitive,
hence cross-coupling reaction under phosphine-free environment is
still a challenge of high importance for the researchers. Recently
different phosphine-free ligands have attracted considerable
attention as competent ligand for the Suzuki–Miyaura reaction,
2
3
reproducibility. Microwave-assisted Suzuki reactions can be
2
4
considered today as an efficient synthetic methodology. With
microwave irradiation, efficient heating of the sample itself is
possible compared to conventional heating where transfer of heat
occurs through reaction vessel walls. This internal heat transfer
helps in minimizing wall effects (no thermal boundary layer) and
reaction mixtures can be heated to high temperatures rapidly.
Therefore with an aim to develop novel catalytic systems for
Suzuki–Miyaura cross-coupling reactions with improved yield
herein, we would like to report a facile and convenient protocol for
the Suzuki–Miyaura reaction of olefinic or aryl bromides with aryl or
heteroaryl boronic acids to afford novel bioactive compounds using
5
6
7
such as N-heterocylic carbenes, diimines, sulfonated Pd-diimine,
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a unique palladium bidentate Schiff base complex (C) as catalyst However, when the temperature of the reaction mixture was
o
under microwave irradiation.
increased to 60 C (thermal heating, oil bath), the yield of product
was improved significantly to 84% in 3h (Table 1, entry 2). It is well
established that in the Suzuki reaction the choice of solvent often
plays a crucial role in the overall performance of a catalyst and to
investigate this effect we have screened different solvents with our
model reaction. Our study reveals ethanol the best solvent for our
catalytic system (Table 1, entry 2) and this might be due to the
better solubility of the reagents and easier reduction of Pd(II) to
Pd(0) and hence a facile entry to the catalytic cycle. The other
Results and discussion
The synthetic route of the chromen-4-one derived ligand is depicted
in Scheme 1. The chromen-4-one based diimine ligand (L) was
synthesized via a simple condensation procedure involving the
reaction of 4-oxo-4H-chromene-3-carbaldehyde with naphthalene-
1
,2 diamine in dry ethanol under reflux to give L. Complex C was
obtained via reaction of the chromen-4-one containing diimine
ligand L and PdCl (CH CN) in acetonitrile for 24h at room
temperature (Scheme 1). The new ligand (L) and the complex (C)
2
3
2
2
5
solvents including mixed-aqueous solvents, neat water and CH CN
3
1
13
gave poor to moderate yields (Table 1, entries 3-5). Although the
solvents like DMF, THF and DMA provided 72-76% yields of the
product (Table 1, entries 6-8).
were elucidated by FTIR, H, C NMR, HRMS and elemental
analysis.
The efficiency of the reaction was studied in different heating
regime for example in microwave condition and to our delight;
reaction proceeded smoothly increasing the yield of 4a to 91%
(
Table 2, entry 1).
a
Table 2. Optimization of base, temperature and time under MWI.
o
c
Entry Solvent Base
Temp. ( C) Time (min) Yield (%)
1
2
3
4
5
6
7
8
9
1
EtOH
EtOH
DMF
THF
K
2
CO
K2CO3
CO
K2CO3
CO
K2CO3
Cs CO
Et N
3
60
60
80
60
80
60
60
60
50
70
18
18
28
30
29
35
18
35
30
18
91
95
80
84
78
52
95
35
65
95
b
b
b
b
b
b
b
b
b
K
2
3
DMA
K
2
3
CH CN
3
EtOH
EtOH
EtOH
EtOH
2
3
Scheme 1. Synthetic route to ligand (L) and complex (C).
3
K
2
CO
K2CO3
3
Initially, to evaluate the efficiency of the bidentate Schiff base
ligands L in Suzuki–Miyaura reaction, we selected 3-bromo-2-(4-
methoxyphenyl)-4H-chromen-4-one 1a and (4-methyl-2-oxo-4-
vinyl-2,4-dihydro-1H-benzo[d][1,3]oxazin-6-yl)boronic acid 3a as
model substrates. The heterocycles such as 3-bromoflavones (1a-c,
0
a
Reaction conditions: 3-bromoflavone (1 mmol), boronic acid (1.2 mmol),
Pd-complex C (0.5 mol %), base (2.5 mmol), Solvent (6 mL) in air, TBAB was
added as an additive for entries 2-10; Isolated yields.
b
c
2
a-c, 5, 6) and boronic acids (3a-c) were synthesized by following
It
was
observed
that
when
0.5
equiv.
of
2
6, 27
the literature procedure.
Initially, the reaction was subjected to room temperature using
ethanol as solvent and K CO as base with 0.5 mol % of the catalyst
C. We were fairly satisfied to see that the reaction proceeded at
room temperature, although only 40% yield of the product was
isolated after a reaction time of 16h (Table 1, entry 1).
tetrabutylammoniumbromide (TBAB) was added into the reaction
mixture as an additive, the product yield improved to 95% (Table 2,
entry 2). The role of addition of TBAB to the reaction mixture might
be to accelerate the reaction and decrease the yields of arene
formed from protodeboronation of the boronic acid due to either
solvation of the organic substrates in the solvent medium or
stabilizing the catalyst by forming a monomolecular layer around
2
3
a
Table 1. Optimization of solvent under conventional heating.
2
8
the Pd metal core in the reaction. The reaction was also studied in
other solvents such as DMF, THF, DMA and acetonitrile under
microwave irradiation and it was seen that irradiation of the
reaction mixture and addition of TBAB enhanced the product yield
and reduced the reaction time compared to conventional heating
o
b
Entry
Solvent
EtOH
EtOH
Temp. ( C)
Time (h)
Yield (%)
(
Table 2, entries 3-6).
1
2
3
4
5
6
7
r.t.
60
60
60
60
80
60
80
16
3
2
2
3
2.5
3
2.5
40
84
65
45
48
72
75
76
We had also screened the effects of different bases on our model
reaction and noticed that the reaction could tolerate common
inorganic bases like K CO and Cs CO and were found to be the
EtOH:H
2
O
2
3
2
3
H
2
O
most effective bases (Table 2, entries 2, 7). Among the bases
CH
3
CN
screened, Et N was found to be less effective and gave only 35%
3
DMF
THF
DMA
yield in 35 min (Table 2, entry 8). The optimized temperature for
o
the same model reaction was found to be 60 C (Table 2, entries 2,
8
a
9, 10).
Reaction conditions: 3-bromoflavone (1 mmol), boronic acid (1.2 mmol),
b
The reaction was subjected to other ligands also like DABCO, di-2-
pyridyl imine, thiosemicarbazone and pyridylmethylamine and
2 3
Pd-complex C (0.5 mol %), K CO (2.5 mmol), Solvent (6 mL) in air; Isolated
yields.
2
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comparative results of these ligands and optimization of catalyst optimized catalyst loading for completion of the reaction (Table 3,
loading of our bidentate Schiff base ligand (L) for Suzuki-Miyaura entry 7). On decreasing the catalyst loading to 0.1 and 0.2 mol %,
coupling reaction was summarized in Table 3. Studies on product yield was also decreased significantly (Table 3, entry 5, 6).
optimization of catalyst quantities reveal that 0.3 mol % is
Table 3. Comparative results of various ligands and optimization of catalyst loading for Suzuki-Miyaura coupling reaction.
Entry
Ligand
Cat. Loading (mol %)
Time (min)
Yield (%)
89
91
84
92
35
58
95
95
1
2
3
4
5
6
7
8
DABCO
Di-2-pyridyl imine
Thiosemicarbazone
Pyridylmethylamine
Bidentate Schiff base ligand (L)
Bidentate Schiff base ligand (L)
Bidentate Schiff base ligand (L)
Bidentate Schiff base ligand (L)
5
2
1
0.5
0.1
0.2
0.3
0.4
2h
50
55
3h
25
25
18
18
o
2 3
Under the optimized reaction conditions (ethanol, K CO , 60 C, 0.3 olefinic and aryl bromides with various boronic acids (Table 4). As
mol % Pd-complex C, TBAB), we have examined the cross-coupling illustrated in Table 4, the results showed that Suzuki-coupling took
reactions of a wide range of electronically and sterically diverse place smoothly to get good-to-excellent yields of coupled products.
a
Table 4. Microwave assisted Suzuki-Miyaura coupling of various halides and boronic acids using C as the catalyst.
b
Entry
Bromo compound
1a
Boronic acid
3a
Product
Yield (%)
1
95
2
1b
3a
91
3
4
1c
1a
3a
3b
89
94
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5
6
1b
1c
3b
3b
92
88
H3CO
OCH3
OCH3
O
O
O
4
f
N
O
H
7
8
1a
1b
3c
3c
90
89
9
1c
3c
87
1
0
1
2a
2b
3a
3a
86
85
1
1
1
1
2
3
4
2c
2a
2b
3a
3b
3b
85
OCH3
H
N
86
85
O
4m
O
N
O
H
4
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1
5
2c
3b
81
1
1
6
7
2a
2b
3c
3c
83
85
1
8
2c
3c
84
1
2
2
9
0
1
5
5
5
3a
3b
3c
90
91
92
2
2
6
3a
89
2
2
3
4
6
6
3b
3c
87
91
a
2 3
Reagent and condition: bromo compound (1 mmol), boronic acid (1.2 mmol), K CO (2.5 mmol), Pd-complex C (0.3 mol%), TBAB (0.25 mmol), ethanol (6
o
b
mL), µw irradiation, 60 C, 18-20 min. Isolated yields.
Furthermore, this protocol was tested on other substrates also as given in Table 5.
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Table 5. Some other examples of microwave assisted Suzuki-Miyaura coupling of various halides and phenyl boronic acids using C as the
a
catalyst.
b
Entry
Bromo compound
Boronic acid
Product
Yield (%)
1
96
2
3
91
93
4
5
93
95
6
7
94
94
a
2 3
Reagent and condition: bromo compound (1 mmol), boronic acid (1.2 mmol), K CO (2.5 mmol), Pd-complex C (0.3 mol%), TBAB (0.25 mmol), ethanol (6
o
b
mL), µw irradiation, 60 C, 18-20 min. Isolated yields.
The assigned structure of new products (4a-r, 5a-c, 6a-c, 1aa-7aa) alkylborate complex. Finally reductive elimination takes place to
1
13
29
were established from their spectroscopic data (IR, H, C NMR and give the coupled product with regeneration of Pd(0)-species
HRMS). For example, compound 4e was obtained as a brown solid. (Scheme 2). The use of microwave irradiation significantly
IR spectrum of 4e showed absorptions at 3265, 1713, 1652, 1641 shortened the reaction times in comparison with thermal heating
-1
and 1555 cm for –NH, >C=O, >C=C< (benzo[d][1,3]oxazin-2(4H)- condition. Microwave might be playing a key role in faster
one moeity), >C=O and >C=C< (flavone moeity) respectively. HRMS generation of Pd(0) from Pd(II) in situ. In addition, it might have
+
of 4e supported a molecular composition of C H NNaO [M+Na] , accelerated the breaking and creation of new bonds in the various
2
9
25
1
6
representing 18 degrees of unsaturation. In the H-NMR spectrum steps of the reaction mechanism. The ligand probably helped in
of 4e, peak at δ ppm 9.40 (s, 1H, D O exchangeable) confirms the preventing quick oxidation of Pd(0) to Pd(II) though the reaction
H
2
presence of -NH group, methyl group occurred at δ
H
ppm 1.68 (s, was performed in the presence of air.
3
H), two methylene protons (-CH ) resonating at δ ppm 2.67-2.63
2
H
(
m, 2H), two -OCH
3
groups resonates at 3.93 ppm, three olefinic
Conclusion
protons appears at δ ppm 5.73-5.65 (m, 1H) and 5.14-5.09 (m, 2H).
H
The present protocol reports a new chromen-4-one-containing
Pd(II)–diimine complex (C) as an efficient catalytic system for
microwave assisted Suzuki–Miyaura reactions of various bromo
compounds with boronic acids to form diverse range of bioactive
flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-ones. Furthermore,
complex C is air-stable and the reactions were completed in 18-20
min. The advantages of this new phosphine-free procedure are
simple operation, good to excellent yields, short reaction times,
broad range of functional groups tolerance and substrates including
nitrogen-containing heterocycles, possibility of performing the
reaction in air. The biological activity of synthesized compounds is
under investigation and will be reported elsewhere. This reaction
will be useful for the construction of a number of bioactive
molecules of pharmaceutical value.
1
3
In C-NMR spectrum, δ
presence of carbonyl group of flavone and benzoxazinone moiety
respectively. Peaks at δ ppm 84.6, 56.3, 56.2, 45.5 and 26.3 also
confirm the presence of quarternary carbon, two –OCH , methylene
c
ppm 173.5 and 162.0 confirms the
c
3
2 3
(CH ) and -CH groups respectively.
If a Pd(II) source is used in a Suzuki reaction, it must be reduced to
Pd(0) before entering the catalytic cycle. After preactivation of the
catalyst, the mechanism of Suzuki reaction involves an oxidative
addition of bromo compound with Pd(0)-species to form the
organo-palladium(II) species followed by the exchange of the anion
attached to palladium for the anion of the base (metathesis).
Meanwhile boron atom of the boronic acid forms borate complex
with the base which enhances the polarisation of the organic ligand
thereby facilitating the transmetalation step between Pd(II) and the
6
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Scheme 2. Reaction mechanism for the in situ activation of catalyst and Suzuki cross-coupling catalytic cycle.
and temperature was being ramped from room temperature to a
desired temperature. Once this temperature was attained, the
process vial was held at this temperature for required time. The
reactions were continuously stirred. Temperature was measured by
an IR sensor. After the experiments a cooling jet cooled the reaction
vessel to ambient temperature.
Synthesis of ligand (L): 4-oxo-4H-chromene-3-carbaldehyde (1.74 g,
10 mmol) was dissolved in dry ethanol (10 ml). Formic acid (90%, 1
drop) was added as a catalyst, followed by addition of naphthalene-
Experimental protocol
All the required chemicals were purchased from Merck and Aldrich
Chemical Company. Pre-coated aluminium sheets (silica gel 60
F254, Merck) were used for thin-layer chromatography (TLC) and
spots were visualized under UV light. Melting points were
performed with Ambassador® and Digital Melting point apparatus
(Nutronics), Popular India. IR spectra were recorded with KBr on
1
13
Thermo Nicolet FT-IR spectrophotometer. H NMR and C NMR
spectra were recorded respectively on Bruker Spectrospin DPX 500
and Jeol Resonance ECX 400II spectrometer using as solvent and
trimethylsilane (TMS) as an internal standard. Spectra were
processed using Bruker Topspin® 3.0.b.8. Splitting patterns are
designated as follows; s = singlet, d = doublet, m = multiplet.
Chemical shift (δ) values are given in ppm. High-resolution mass
spectra (HRMS) were obtained on a Brüker micrOTOF™-Q II mass
spectrometer (ESIMS).
Microwave Irradiation Experiment. All microwave experiments
were carried out in a dedicated Anton Paar Monowave-300 reactor,
operating at a frequency of 2.455 GHz with continuous irradiation
power of 0 to 850 W. The reactions were performed in a G-4
Borosilicate glass vial sealed with Teflon septum and placed in a
microwave cavity. Initially, microwave of required power was used
1
, 2 diamine (1.58 g, 10 mmol). The reaction mixture was stirred at
ambient temperature for 24h. Product L, which precipitated from
o
solution upon cooling to -10 C, was isolated by filtration and
1
washed with cold ethanol as yellow solid. Yield: 85%. H NMR (500
MHz, CDCl , ppm): δ 8.44-8.35 (m, 1H), 8.28-8.20 (m, 2H), 7.98-7.96
3
(
7
(
m, 1H), 7.83-7.73 (m, 2H), 7.56-7.55 (m, 1H), 7.52-7.47 (m, 3H),
.43-7.40 (m, 2H), 7.33-7.26 (m, 2H), 7.25-7.21 (m, 2H), 7.15-7.13
m, 1H), 6.82 (m, 1H). C NMR (100 MHz, CDCl3, ppm): δ 178.3,
13
1
1
1
61.8, 154.7, 151.8, 143.1, 137.4, 136.4, 134.8, 127.6, 126.3, 126.0,
25.1, 124.6, 121.9, 120.3, 118.2, 113.2, 108.8. FTIR (KBr, v = cm ):
-1
715, 1645, 1624. Anal. Calcd (%) for C H N O : C, 76.59; H, 3.86;
3
0 18 2 4
N, 5.95. Found: C, 76.43; H, 3.72; N, 5.79. HRMS (ESI+): m/z calcd
+
for C H N NaO [M+Na] : 493.1158, found: 493.1158.
30
18
2
4
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Synthesis of Pd/complex (C): 125-ml Schlenk flask equipped with a NMR (100 MHz, CDCl , ppm): δ173.3, 161.9, 155.6, 153.1, 139.4,
3
magnetic stir bar was charged with PdCl
mmol) and chromen-4-one/diimine ligand L (47 mg, 0.1 mmol) and 115.7, 114.7, 107.1, 82.4, 61.2, 56.5, 25.7. FTIR (KBr, v = cm ): 3269,
flushed with nitrogen. CH CN (20 ml) was added by syringe, and the 2959, 1713, 1690, 1652, 1621, 1555, 1513, 1473, 1359, 1336, 1321.
resulting solution was sealed under nitrogen and stirred for 24h, HRMS (ESI+): m/z calcd. for C H NO [M+H] : 522.1523, found:
2 3 2
(CH CN) (31 mg, 0.1 134.4, 132.3, 129.4, 127.9, 127.5, 126.7, 125.9, 124.5, 123.5, 118.0,
-1
3
+
2
9
26
7
during which time a yellow/orange solid precipitated out from the 522.1501.
solution. The solid was isolated by filtration, washed with diethyl 4-allyl-6-(2-(4-methoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-methyl-
o
ether, and dried under vacuum. Yield: 82%, mp >220 C. Anal. Calcd 1H-benzo[d][1,3]oxazin-2(4H)-one (4d). Yield: 94% as brown solid,
o
1
(
%) for C H Cl N O Pd: C, 55.62; H, 2.80; Cl, 10.95; N, 4.32. Found: mp 124-125 C; H NMR (500 MHz, CDCl ppm): δ 9.74 (s, 1H, D O
3
0
1
8
2
2
4
3
,
2
C, 55.48; H, 2.92; Cl, 10.72; N, 4.23.
exchangeable), 8.27 (d, J = 8 Hz, 1H), 7.72 (s, 1H), 7.53-7.50 (m, 1H),
General procedure for synthesis of compounds (4a-r, 5a-c, 6a-c): 7.46-7.42 (m, 1H), 7.31 (d, J = 8.5 Hz, 2H), 7.17 (s, 1H), 7.01 (s, 2H),
To a G-4 process vial capped with Teflon septum was added 3- 7.00 (d, J = 8.5 Hz, 1H), 6.78 (d, J = 8.5 Hz, 1H), 5.75-5.66 (m, 1H),
1
3
bromo flavone (1 mmol), boronic acid (1.1 mmol), Pd-complex C 5.13-5.01 (m, 2H), 3.9 (s, 3H), 2.69-2.60 (m, 2H), 1.67 (s, 3H).
C
(
0.3 mol%, 1.6 mg), TBAB (0.25 mmol), K CO (2.5 mmol) and 6 ml NMR (125 MHz, CDCl , ppm): δ173.5, 162.0, 155.7, 152.5, 151.6,
2
3
3
of ethanol. After a pre-stirring for one minute, the vial was 148.6, 135.2, 134.3, 133.7, 132.0, 131.1, 127.1, 125.9, 123.3, 121.8,
subjected to microwave irradiation time of 18-20 minute at 60 °C. It 120.5, 117.9, 116.4, 115.7, 112.5, 110.6, 108.6, 84.3, 56.3, 45.5,
-1
was then cooled to room temperature, diluted with water, and 26.3. FTIR (KBr, v = cm ): 3267, 2975, 1713, 1692, 1652, 1611, 1557,
extracted with EtOAc for three times. The organic phase was dried 1505, 1463, 1350, 1328, 1306. HRMS (ESI+): m/z calcd. for
+
with Na
2
SO
4
and concentrated to yield the product. The crude
C
28
H
24NO
5
[M+H] : 454.1648, found: 454.1636.
material was chromatographed on a silica gel column eluting with a 4-allyl-6-(2-(3,4-dimethoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-
mixture of ethyl acetate and hexane. (The purified products were methyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4e). Yield: 92% as
o
1
identified by FTIR, NMR and HRMS spectra).
brown solid, mp 117-119 C; H NMR (500 MHz, CDCl3, ppm): δ 9.40
s, 1H, D O exchangeable), 8.29 (d, J = 8Hz, 1H), 7.91 (s, 1H), 7.27 (t,
J = 8 Hz, 1H), 7.53-7.45 (m, 2H), 7.32 (d, J = 8 Hz, 1H), 7.18 (s, 1H),
(
2
Characterization data:
6
-(2-(4-methoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-vinyl- 7.10 (d, J = 18 Hz, 2H), 6.79 (d, J = 8.5 Hz, 1H), 5.73-5.65 (m, 1H),
1
3
1H-benzo[d][1,3]oxazin-2(4H)-one (4a). Yield: 95% as brown solid, 5.14-5.09 (m, 2H), 3.93 (d, 6H), 2.67-2.63 (m, 2H), 1.68 (s, 3H).
C
o
1
mp 160-168 C; H NMR (500 MHz, CDCl3, ppm): δ9.08 (s, 1H, D
2
O
3
NMR (125 MHz, CDCl , ppm): δ173.5, 162.0, 155.7, 152.6, 151.6,
exchangeable), 8.27 (d, J = 8Hz, 1H), 7.80 (d, J = 9Hz, 1H), 7.7 (t, J = 148.6, 135.2, 134.3, 133.7, 132.0, 131.1, 127.1, 126.6, 125.9, 125.1,
8
=
=
.5 Hz, 1H), 7.48 (d, J = 8 Hz, 1H), 7.44 (t, J = 7.5 Hz, 1H), 7.37 (dd, J 123.4, 121.8, 120.5, 118.0, 116.4, 115.7, 112.5, 110.7, 108.7, 84.6,
1.5, 8.5 Hz, 1H), 7.13 (d, J = 8Hz, 1H), 7.08-7.02 (m, 3H), 6.87 (d, J 56.3, 56.2, 45.5, 26.3. FTIR (KBr, v = cm ): 3265, 2975, 1713, 1652,
-1
8Hz, 1H), 6.06-5.97 (m, 1H), 5.26-5.06 (m, 2H), 3.90 (s, 3H), 1.82 1641, 1555, 1513, 1473, 1349, 1331, 1311. HRMS (ESI+): m/z calcd.
1
3
+
3 6
(s, 3H). C NMR (125 MHz, CDCl , ppm): δ174.8, 164.5, 161.8, for C29H25NNaO [M+Na] : 506.1574, found: 506.1575.
1
1
5
1
55.9, 153.0, 139.4, 134.2, 132.3, 131.5, 129.4, 127.5, 127.3, 126.8, 4-allyl-4-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-4H-chromen-
25.9, 124.5, 123.6, 120.0, 117.7, 115.7, 114.8, 113.8, 113.7, 87.7, 3-yl)-1H-benzo[d][1,3]oxazin-2(4H)-one (4f). Yield: 88% as brown
-1
o
1
5.6, 25.7.FTIR (KBr, v = cm ): 3256, 2955, 1709, 1655, 1615, 1587, solid, mp 118-120 C; H NMR (500 MHz, CDCl3, ppm): δ 10.08 (s,
505, 1463, 1345, 1333, 1306. HRMS (ESI+): m/z calcd. for 1H, D O exchangeable), 8.19 (dd, J = 8 Hz, 1H), 7.75 (s, 1H), 7.69-
2
+
C
27
H
22NO
5
[M+H] : 440.1492, found : 440.1495.
7.64 (m, 1H), 7.55-7.47 (m, 1H), 7.43-7.35 (m, 1H), 7.12-7.10 (m,
2H), 7.04 (s, 1H), 6.80-6.78 (m, 1H), 5.68-5.60 (m, 1H), 5.08-5.04 (m,
6-(2-(3,4-dimethoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-
1
3
vinyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4b). Yield: 91% as brown 2H), 3.90 (s, 6H), 3.8 (s, 3H), 2.64-2.54 (m, 2H), 1.62 (s, 3H). C NMR
o
1
solid, mp 139-143 C; H NMR (500 MHz, CDCl3, ppm): δ 8.93 (s, 1H, (125 MHz, CDCl
O exchangeable), 8.28 (d, J = 8 Hz, 1H), 7.70 (t, J = 8 Hz, 1H), 7.51 134.4, 133.7, 132.0, 131.1, 127.9, 127.2, 126.7, 126.6, 126.0, 121.8,
t, J = 8Hz, 2H), 7.46 (d, J = 7.5 Hz, 1H), 7.35 (dd, J = 1.5, 8 Hz, 1H), 121.4, 120.5, 118.0, 116.4, 115.7, 107.2, 84.4, 61.2, 56.6, 45.5, 26.3.
3
, ppm): δ173.4, 162.0, 153.1, 152.4, 140.6, 135.0,
D
(
2
-1
7
1
3
1
1
1
2
.13 (d, J = 7.5 Hz, 1H), 7.06 (t, J = 7.5 Hz, 1H), 7.00 (d, J = 8.5 Hz, FTIR (KBr, v = cm ): 3235, 2934, 1716, 1686, 1645, 1592, 1463,
H), 6.87 (d, J = 7.5 Hz, 1H), 6.05-5.96 (m, 1H), 5.25-5.05 (m, 2H), 1406. HRMS (ESI+): m/z calcd. for C30H27NNaO [M+Na] : 536.1679,
7
+
13
3
.95 (s, 6H), 1.81 (s, 3H). C NMR (125 MHz, CDCl , ppm): δ173.4, found: 536.1678.
61.9, 155.7, 151.6, 148.6, 139.4, 134.6, 134.2, 132.3, 129.4, 127.5, 6-(2-(4-methoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-
26.7, 125.8, 125.2, 124.5, 123.8, 123.5, 123.3, 121.9, 117.9, 114.8, pentyl-1H-benzo [d][1,3]oxazin-2(4H)-one (4g). Yield: 90% as white
12.6, 110.7, 108.7, 83.8, 56.2, 25.7. FTIR (KBr, v = cm ): 3267, solid, mp 113-114 C; H NMR (500 MHz, CDCl3, ppm): δ 9.90 (s, 1H,
975, 1713, 1652, 1611, 1557, 1505, 1463, 1350, 1328, 1306. HRMS O exchangeable), 8.14 (dd, J = 8 Hz, 1H), 7.78 (d, J = 8.5 Hz, 1H),
-1
o
1
D
2
+
(ESI+): m/z calcd. for C28
H23NNaO
6
[M+Na] :492.1417, found : 7.67 (t, J = 8 Hz, 1H), 7.42 (m, 2H), 7.28 (d, J = 8.5 Hz, 1H), 7.15 (s,
2H), 6.99 (d, J = 8.5 Hz, 2H), 6.79 (d, J = 8.5 Hz, 1H), 3.86 (s, 3H),
4
4
4
92.1431.
-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-4H-chromen-3-yl)-
-vinyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4c). Yield: 89% as brown 3H). C NMR (125 MHz, CDCl
1.91-1.87 (m, 2H), 1.64 (s, 3H), 1.37-1.24 (m, 6H), 0.82 (t, J = 8Hz,
1
3
3
, ppm): δ 178.0, 155.9, 155.4, 152.8,
o
1
solid, mp 140-145 C; H NMR (500 MHz, CDCl3, ppm): δ 8.95 (s, 1H, 146.4, 146.0, 133.9, 133.7, 131.7,127.0, 126.9,125.8, 125.3, 124.2,
O exchangeable), 8.28 (d, J = 8Hz, 1H), 7.72-7.68 (m, 1H), 7.51 (s, 118.0, 116.5, 115.7, 113.3, 112.6, 105.5, 85.4, 41.0, 31.8, 27.1, 23.2,
D
2
-1
1
7
H), 7.36 (dd, J = 2, 8.5 Hz, 1H), 7.12 (d, J = 7.5 Hz, 1H), 7.06 (t, J = 22.5, 14.1. FTIR (KBr, v = cm ): 3228, 2934, 2869, 1705, 1687, 1615,
.5 Hz, 1H), 7.00 (d, J = 8.5 Hz, 1H), 6.87 (d, J = 8 Hz, 1H), 6.04-5.96 1463, 1406, 1352. HRMS (ESI+): m/z calcd. for C30 29NNaO
H
5
1
3
+
(m, 1H), 5.25-5.05 (m, 2H), 3.96 (s, 3H), 3.95 (s, 6H), 1.81 (s, 3H).
C
[M+Na] : 506.1937, found: 506.1921.
8
| J. Name., 2012, 00, 1-3
This journal is © The Royal Society of Chemistry 20xx
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Page 9 of 12
Journal Name
PleaseRd So Cn oA t da vd aj un s ct ems argins
View Article Online
DOI: 10.1039/C5RA15274G
ARTICLE
6-(2-(3,4-dimethoxyphenyl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-
(125 MHz, CDCl , ppm): δ174.7, 164.1, 161.5, 156.5, 153.6, 139.1,
3
pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4h). Yield: 89% as white 138.5, 134.1, 134.0, 133.6, 132.2, 131.4, 129.3, 127.4, 126.8, 125.4,
o
1
solid, mp 109-110 C; H NMR (500 MHz, CDCl ppm): δ 9.61 (s, 1H, 124.2, 123.7, 123.5, 120.1, 117.5, 115.7, 84.3, 60.5, 55.8, 25.7.
3
,
+
D
2
O exchangeable), 7.80-7.69 (m, 1H), 7.51 (t, J = 7.5 Hz, 1H), 7.46- HRMS (ESI+): m/z calcd. for C29
.41 (m, 1H), 7.31 (d, J = 8.5 Hz, 1H), 7.15 (s, 1H), 6.78 (d, J = 8 Hz, found: 521.1682.
H), 3.95-3.96 (d, 6H), 1.92-1.88 (m, 2H), 1.65 (s, 3H), 1.37-1.28 (m, 4-allyl-6-(2-(4-methoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-
H), 0.84 (t, J = 8 Hz, 3H). C NMR (125 MHz, CDCl , ppm): δ173.4, methyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4m). Yield: 86% as
61.9, 152.7, 152.9, 151.6, 148.6, 134.2, 133.6, 131.8, 127.0, 126.9, Brown solid, mp 138-141 C; H NMR (500 MHz, CDCl3, ppm): δ 9.61
26 2 6
H N NaO [M+Na] : 521.1683,
7
1
8
1
1
1
1
3
3
o
1
26.7, 125.8, 125.2, 123.3, 121.8, 117.9, 116.5, 115.8, 112.6, 110.7, (s, 1H, D O exchangeable), 8.26 (dd, J = 1, 8 Hz, 1H), 7.80 (d, J = 8.5
2
08.7, 85.5, 56.3, 56.2, 41.0, 31.9, 27.2, 23.3, 22.5, 14.1. HRMS Hz, 2H), 7.68 (t, J = 7.5 Hz, 1H), 7.48 (d, J = 8.5 Hz, 1H), 7.43 (t, J = 7
+
(
ESI+): m/z calcd. for C H NNaO [M+Na] : 536.2043, found: Hz, 1H), 7.32 (dd, J = 1.5, 8.5 Hz, 1H), 7.18 (s, 1H), 7.02 (d, J = 8.5 Hz,
31
31
6
5
4
4
36.2034.
-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-4H-chromen-3-yl)-
-pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4i). Yield: 87% as (s, 3H). C NMR (125 MHz, CDCl
2H), 6.77 (d, J = 8.5 Hz, 1H), 6.23 (s, 1H, D
2
O exchangeable), 5.72-
5.65 (m, 1H), 5.14-5.09 (m, 2H), 3.89 (s, 3H, 2.70-2.62 (m, 2H), 1.68
1
3
3
, ppm): δ175.0, 164.6, 161.8,
o
1
white solid, mp 155-158 C; H NMR (500 MHz, CDCl ppm): δ 9.63 155.9, 152.5, 134.3, 133.7, 132.0, 131.9, 131.5, 131.1, 127.2, 127.1,
3,
(
2
s, 1H, D O exchangeable), 8.28 (d, J = 8Hz, 1H), 7.72 (t, J = 8 Hz, 126.8, 126.6, 125.9, 120.5, 120.0, 117.7, 116.6, 115.7, 113.7, 84.3,
H), 7.52-7.44 (m, 2H), 7.31 (d, J = 8.5 Hz, 1H), 7.16 (s, 1H), 7.09 (s, 55.6, 45.5, 26.3. FTIR (KBr, v = cm ): 3394, 3293, 2957, 2930, 1712,
H), 6.79 (d, J = 8 Hz, 1H), 3.93 (d, 9H), 1.92-1.89 (m, 2H), 1.65 (s, 1686, 1646, 1610, 1572, 1355. HRMS (ESI+): m/z calcd. for
-1
1
2
3
CDCl
1
1
1
3
+
H), 1.31-1.23 (m, 6H), 0.83 (t, J = 7 Hz, 3H). C NMR (125 MHz,
, ppm): δ173.3, 161.9, 155.6, 153.1, 152.9, 140.6, 134.4, 133.6, 4-allyl-6-(2-(3,4-dimethoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-
31.8, 127.9, 127.0, 126.9, 126.7, 126.0, 121.8, 118.0, 116.5, 115.8, yl)-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4n). Yield: 85% as
28 24 2 4
C H N NaO [M+Na] : 475.1628, found: 475.1631.
3
o
1
09.1, 107.2, 85.5, 61.1, 56.5, 41.0, 31.8, 27.2, 23.2, 22.5, 14.1. Brown solid, mp 160-165 C; H NMR (500 MHz, CDCl3, ppm): δ 9.66
+
HRMS (ESI+): m/z calcd. for C32
H
33NNaO
7
[M+Na] : 566.2149, found: (s, 1H, D
2H), 7.52 (d, J = 8 Hz, 1H), 7.46 (t, J = 7 Hz, 1H), 7.31 (dd, J = 1.5, 8
-(2-(4-methoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-methyl- Hz, 1H), 7.17 (d, J = 1.5 Hz, 1H), 7.09 (s, 2H), 6.78 (d, J = 8.5 Hz, 1H),
-vinyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4j). Yield: 86% as brown 5.71-5.67 (m, 1H), 5.52 (s, 1H, D O exchangeable), 5.13-5.09 (m,
2
O exchangeable), 8.28 (dd, J = 1, 8 Hz, 1H), 7.74-7.71 (m,
5
6
4
66.2151.
2
o
1
13
solid, mp 159-161 C; H NMR (500 MHz, CDCl3, ppm): δ 9.49 (s, 1H, 2H), 3.94 (s, 3H), 2.69-2.60 (m, 2H), 1.67 (s, 3H). C NMR (125 MHz,
O exchangeable), 9.08 (s, 1H, D O exchangeable), 8.28 (d, J = 8 CDCl , ppm): δ174.1, 152.4, 150.5, 150.3, 148.5, 139.4, 135.2, 133.7,
Hz, 1H), 7.79 (d, J = 9Hz, 1H), 7.70 (t, J = 8.5 Hz, 1H), 7.37 (dd, J = 132.2, 132.0, 131.1, 127.2, 126.6, 124.4, 123.5, 122.3, 121.9, 120.5,
D
2
2
3
1
8
3
.5, 8.5 Hz, 1H), 7.13 (d, J = 8 Hz, 1H), 7.08-7.02 (m, 2H), 6.87 (d, J = 116.4, 115.7, 112.6, 110.6, 84.3, 56.1, 56.0, 45.5, 26.3. FTIR (KBr, v =
-1
Hz, 1H), 6.84 (d, J = 8 Hz, 1H), 6.06-6.00 (m, 1H), 5.26-5.06 (m, 2H), cm ): 3375, 3290, 2987, 2927, 1713, 1677, 1648, 1601, 1407, 1352.
1
3
+
.90 (s, 3H), 1.82 (t, J = 8Hz, 3H). C NMR (125 MHz, CDCl
3
, ppm): HRMS (ESI+): m/z calcd. for C29
H
26
N NaO
2
5
[M+Na] : 505.1733,
δ174.8, 164.5, 161.8, 155.9, 139.4, 138.7, 134.6, 134.2, 132.3, found: 505.1733.
1
5
1
31.5, 129.4, 127.5, 123.6, 120.0, 117.7, 115.7, 114.8, 113.7, 87.7, 4-allyl-4-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-1,4-
-1
5.6, 25.7. FTIR (KBr, v = cm ): 3305, 3267, 2975, 1714, 1692, 1641, dihydroquinolin-3-yl)-1H-benzo[d][1,3]oxazin-2(4H)-one
(4o).
Yield: 81% as Brown solid, mp 178-180 C; H NMR (500 MHz, CDCl3,
ppm): δ 9.71 (s, 1H, D O exchangeable), 9.20 (s, 1H, D
exchangeable), 8.24 (d, J = 8 Hz, 1H), 7.83 (d, J = 8 Hz, 1H), 7.63-7.58
o
1
557, 1505, 1463. HRMS (ESI+): m/z calcd. for C27
H
22
N
2
NaO
4
+
[M+Na] : 461.1471, found : 461.1467.
2
2
O
6-(2-(3,4-dimethoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-
methyl-4-vinyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4k). Yield: 85% (m, 2H), 7.34-7.28 (m, 2H), 7.15 (s, 1H), 7.03 (s, 1H), 6.78 (d, J = 8.5
o
1
as Brown solid, mp 147-150 C; H NMR (500 MHz, CDCl3, ppm): δ Hz, 1H), 5.71-5.63 (m, 1H), 5.12-5.07 (m, 2H), 3.77 (s, 9H), 2.67-2.58
1
3
9
8
7
1
2 2 3
.31 (s, 1H, D O exchangeable), 8.93 (s, 1H, D O exchangeable), (m, 2H), 1.65 (s, 3H). C NMR (125 MHz, CDCl , ppm): δ 173.9,
.28 (d, J = 8Hz, 1H), 7.70 (t, J = 8 Hz, 1H), 7.51 (t, J = 8.5 Hz, 2H), 152.8, 152.3, 150.5, 139.4, 138.9, 135.1, 133.7, 131.9, 131.1, 130.3,
.46 (d, J = 8Hz, 1H), 7.36 (dd, J = 1.5, 8.5 Hz, 1H), 7.13 (d, J = 7.5 Hz, 127.1, 126.5, 126.0, 124.5, 123.4, 121.7, 120.4, 118.7, 116.4, 115.6,
H), 7.06 (t, J = 7.5 Hz, 1H), 6.99 (d, J = 8.5 Hz, 1H), 6.87 (d, J = 7.5 106.8, 84.2, 60.9, 56.3, 45.5, 26.3. HRMS (ESI+): m/z calcd. for
[M+Na] : 535.1839, found: 535.1841.
3
, ppm): δ174.8, 164.5, 161.8, 6-(2-(4-methoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-methyl-
56.0, 153.2, 139.4, 138.7, 134.6, 134.2, 133.8, 132.3, 131.5, 129.4, 4-pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4p). Yield: 83% as
27.5, 126.9, 125.9, 124.5, 123.8, 123.6, 120.1, 117.7, 115.8, 114.8, white solid, mp 145-148 C; H NMR (500 MHz, CDCl3, ppm): δ 9.90
13.7, 84.3, 55.8, 25.8. HRMS (ESI+): m/z calcd. for C28 NaO (s, 1H, D O exchangeable), 8.24 (d, J = 8 Hz, 1H), 7.78 (d, J = 8.5 Hz,
+
Hz, 1H), 6.05-5.98 (m, 1H), 5.20-5.05 (m, 2H), 3.95 (s, 6H), 1.81 (t, J
C
30
H
28
N
2
NaO
6
1
3
=
1
1
1
8 Hz, 3H). C NMR (125 MHz, CDCl
o
1
H
24
N
2
5
2
+
[
4
M+Na] : 491.1577, found: 491.1572.
-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-1,4-
dihydroquinolin-3-yl)-4-vinyl-1H-benzo[d][1,3]oxazin-2(4H)-one
1H), 7.65 (t, J = 7.5 Hz, 1H), 7.46-7.39 (m, 2H), 7.29 (d, J = 8.5 Hz,
1H), 7.15 (s, 2H), 7.00 (d, J = 8.5 Hz, 2H), 6.80 (d, J = 8.5 Hz, 1H), 5.82
(s, 1H, D
4l). Yield: 85% as Brown solid, mp 112-115 C; H NMR (500 MHz, 3H), 1.37-1.29 (m, 6H), 0.82 (s, 3H). C NMR (125 MHz, CDCl
CDCl3, ppm): δ 9.31 (s, 1H, D O exchangeable), 8.93 (s, 1H, D ppm): δ 174.9, 164.5, 161.8, 155.9, 153.0, 145.1, 134.2, 131.7,
exchangeable), 8.26 (d, J = 8Hz, 1H), 7.70-7.68 (m, 1H), 7.50 (s, 1H), 131.5, 127.2, 127.0, 126.9, 126.8, 125.9, 120.0, 117.6, 116.5, 115.7,
2
O exchangeable), 3.86 (s, 3H), 1.92-1.87 (m, 2H), 1.64 (s,
o
1
13
(
3
,
2
2
O
7
1
5
.34 (dd, J = 2, 8.5 Hz, 1H), 7.11 (d, J = 7.5 Hz, 1H), 7.04 (t, J = 7.5 Hz, 113.7, 85.4, 55.6, 41.0, 31.8, 27.1, 23.2, 22.5, 14.0. FTIR (KBr, v =
-1
H), 6.98 (d, J = 8.5 Hz, 1H), 6.86(d, J = 8 Hz, 1H), 6.03-5.94 (m, 1H), cm ): 3375, 3290, 2987, 2927, 1710, 1677, 1643, 1407, 1352. HRMS
1
3
.23-5.03 (m, 2H), 3.95 (s, 3H), 3.94 (s, 6H), 1.79 (s, 3H). C NMR
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DOI: 10.1039/C5RA15274G
ARTICLE
Journal Name
+
(
ESI+): m/z calcd. for C H N NaO [M+Na] : 505.2097, found: = 7.5 Hz, 1H), 7.36 (t, J = 8 Hz, 1H), 7.29 (d, J = 7 Hz, 1H), 7.12 (d, J =
30 30 2 4
5
05.2096.
-(2-(3,4-dimethoxyphenyl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-
20 Hz, 2H), 6.79 (d, J = 8 Hz, 1H), 6.58 (s, 1H), 1.91-1.86 (m, 2H),
1
3
6
1.64 (s, 3H), 1.37-1.23 (m, 6H), 0.82 (t, J = 8 Hz, 3H). C NMR (125
, ppm): δ178.0, 155.9, 155.4, 152.8, 146.4, 146.0, 133.9,
5% as white solid, mp 117-118 C; H NMR (500 MHz, DMSO ppm): 133.7, 131.7, 127.0, 126.9, 125.8, 125.3, 124.2, 118.0, 116.5, 115.7,
methyl-4-pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one (4q). Yield: MHz, CDCl
8
δ
3
o
1
,
12.18, (s, 1H,
D
2
O
exchangeable), 10.28 (s, 1H,
D
2
O
113.3, 112.6, 105.5, 85.4, 41.0, 31.8, 27.1, 23.2, 22.5, 14.1. HRMS
+
exchangeable), 8.16 (d, J = 8 Hz, 1H), 7.68 (d, J = 3.5 Hz, 2H), 7.41- (ESI+): m/z calcd. for C H NNaO [M+Na] : 466.1624, found:
2
7
25
5
7
3
0
.38 (m, 3H), 7.23-7.13 (m, 2H), 7.02 (s, 1H), 6.82 (d, J = 8.5 Hz, 1H), 466.1636.
.84 (s, 3H), 3.82 (s, 3H), 1.91 (t, J = 13 Hz, 2H), 1.56 (s, 3H), 1.28- 6-(2-(furan-2-yl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-methyl-4-vinyl-
1
3
3
.80 (m, 6H), 0.79 (t, J = 7 Hz, 3H). C NMR (125 MHz, CDCl , ppm): 1H-benzo[d][1,3]oxazin-2(4H)-one (6a). Yield: 89% as brown solid,
o
1
δ 173.4, 161.9, 155.6, 152.9, 151.6, 148.6, 134.2, 133.6, 131.8, mp 127-130 C; H NMR (500 MHz, CDCl ppm): δ 9.17 (s, 1H, D O
3,
2
126.9, 126.6, 125.8, 125.2, 123.3, 121.8, 117.9, 116.5, 115.8, 112.5, exchangeable), 8.75 (s, 1H, D
2
O exchangeable), 8.19 (d, J = 9 Hz,
1
10.7, 108.7, 85.5, 56.3, 56.2, 41.0, 31.8, 27.2, 23.2, 22.5, 14.1. 1H), 7.66 (t, J = 7.5 Hz, 1H), 7.61 (m, 2H), 7.48 (d, J = 8.5 Hz, 2H),
+
HRMS (ESI+): m/z calcd. for C31
found: 535.2170.
32 2 5
H N NaO [M+Na] : 535.2203, 7.38 (t, J = 7.5 Hz, 1H), 7.12 (d, J = 2.5 Hz, 1H), 6.78 (s, 1H), 6.59 (s,
13
1H), 6.04-5.96 (m, 1H), 5.24-5.05 (m, 2H), 1.81 (s, 3H). C NMR (100
MHz, CDCl , ppm): δ 178.1, 155.8, 155.3, 145.9, 139.4, 138.7, 133.9,
132.2, 129.3, 127.4, 125.8, 125.3, 124.5, 123.5, 118.0, 116.5, 115.7,
4-methyl-6-(4-oxo-2-(3,4,5-trimethoxyphenyl)-1,4-
3
dihydroquinolin-3-yl)-4-pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one
o
1
-1
(
4r). Yield: 84% as white solid, mp 110-113 C; H NMR (500 MHz, 114.7, 113.3, 112.7, 105.57, 84.2. FTIR (KBr, v = cm ): 3486, 3229,
DMSO ppm): δ 12.25 (s, 1H, D O exchangeable), 10.27 (s, 1H,D 2869, 1717, 1693, 1645, 1546, 1462, 1341, 1259. HRMS (ESI+): m/z
exchangeable), 8.29-8.22 (m, 1H), 8.15 (t, J = 8 Hz, 1H), 7.41-7.38 calcd. for C24
,
2
2
O
+
H N
18 2
NaO
4
[M+Na] : 421.1158, found: 421.1152.
(m, 4H), 7.28 (s, 1H), 6.93 (d, J = 21.5 Hz, 1H), 6.82 (d, J = 8.5 Hz, 4-allyl-6-(2-(furan-2-yl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-methyl-
1
H), 3.83 (s, 6H), 3.74 (s, 3H), 1.93-1.74 (m, 2H), 1.56 (s, 3H), 1.27- 1H-benzo[d][1,3]oxazin-2(4H)-one (6b). Yield: 87% as brown solid,
1
3
o
1
1.16 (m, 6H), 0.79 (t, J = 10 Hz, 3H). C NMR (125 MHz, CDCl
3
,
2
mp 146-148 C; H NMR (400 MHz, CDCl3, ppm): δ 9.90 (s, 1H, D O
ppm): δ 173.3, 161.9, 155.6, 153.1, 152.9, 140.6, 134.4, 133.6, exchangeable), 8.17 (dd, J = 2, 10 Hz, 1H), 7.67-7.63 (m, 1H), 7.59
131.8, 127.9, 127.0, 126.9, 126.7, 126.0, 121.8, 118.0, 116.5, 115.8, (d, J = 1 Hz, 1H), 7.47 (d, J = 10 Hz, 1H), 7.39-7.35 (m, 1H), 7.30-7.27
1
09.1, 107.2, 85.5, 61.1, 56.5, 41.0, 31.8, 27.2, 23.2, 22.5, 14.1. (m, 1H), 7.15 (d, J = 2.5 Hz, 1H), 7.11 (d, J = 4.5 Hz, 1H), 6.80 (d, J =
+
HRMS (ESI+): m/z calcd. for C32
H
34
N
2
NaO
6
[M+Na] : 565.2309, 10.5 Hz, 1H), 6.59-6.57 (m, 1H), 6.24 (s, 1H, D
2
O exchangeable),
found: 565.2304.
5.73-5.63 (m, 1H), 5.12-5.07 (m, 2H), 2.69-2.58 (m, 2H), 1.66 (s, 3H).
1
3
6-(2-(furan-2-yl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-vinyl-1H-
3
C NMR (125 MHz, CDCl , ppm): δ 178.2, 156.1, 155.4, 152.5,
benzo[d][1,3]oxazin-2(4H)-one (5a). Yield: 90% as brown solid, mp 146.5, 146.1, 134.0, 132.0, 131.2, 127.1, 126.6, 125.9, 125.4, 124.3,
o
1
9
7-99 C; H NMR (500 MHz, CDCl3, ppm): δ 8.75 (s, 1H, D
exchangeable), 8.19 (d, J = 7.5 Hz, 1H), 7.65 (t, J = 8 Hz, 1H), 7.61 (m, 26.3. FTIR (KBr, v = cm ): 3492, 3278, 2849, 1715, 1689, 1665, 1609,
H), 7.48 (d, J = 8.5 Hz, 2H), 7.38 (t, J = 7.5 Hz, 1H), 7.12 (d, J = 2.5 1565, 1412, 1343, 1259. HRMS (ESI+): m/z calcd. for C25 NaO
4
2
O
121.8, 120.5, 118.1, 116.5, 115.7, 113.4, 112.8, 105.5, 84.3, 45.6,
-1
2
H
20
N
2
+
Hz, 1H), 6.78 (s, 1H), 6.59 (s, 1H), 6.04-5.96 (m, 1H), 5.24-5.05 (m, [M+Na] : 435.1315, found: 435.1314.
H), 1.81 (s, 3H). C NMR (100 MHz, CDCl
55.3, 145.9, 139.4, 138.7, 133.9, 132.2, 129.3, 127.4, 125.8, 125.3, pentyl-1H-benzo[d][1,3]oxazin-2(4H)-one (6c). Yield: 91% as brown
24.5, 123.5, 118.0, 116.5, 115.7, 114.7, 113.3, 112.7, 105.57, 84.2. solid, mp 153-157 C; H NMR (500 MHz, CDCl3, ppm): δ 9.69 (s, 1H,
FTIR (KBr, v = cm ): 3290, 2987, 1712, 1677, 1652, 1635, 1586,
422, 1352. HRMS (ESI+): m/z calcd. for C24
22.0998, found: 422.0995.
1
3
2
1
1
3
, ppm): δ 178.0, 155.9, 6-(2-(furan-2-yl)-4-oxo-1,4-dihydroquinolin-3-yl)-4-methyl-4-
o
1
-
1
D
2
O exchangeable), 8.17 (d, J = 6.5 Hz, 1H), 7.64-7.59 (m, 2H), 7.46
[M+Na] : (d, J = 7.5 Hz, 1H), 7.36 (t, J = 8Hz, 1H), 7.29 (d, J = 7 Hz, 1H), 7.12 (d,
J = 20 Hz, 2H), 6.79 (d, J = 8 Hz, 1H), 6.58 (s, 1H), 4.23 (s, 1H, D
exchangeable), 1.91-1.86 (m, 2H), 1.64 (s, 3H), 1.37-1.23 (m, 6H),
+
1
4
H17NNaO
5
2
O
4
-allyl-6-(2-(furan-2-yl)-4-oxo-4H-chromen-3-yl)-4-methyl-1H-
1
3
0
.82 (t, J = 7Hz, 3H). C NMR (125 MHz, CDCl
3
, ppm): δ 178.0,
benzo[d][1,3]oxazin-2(4H)-one (5b). Yield: 91% as brown solid, mp
o
1
155.9, 155.4, 152.8, 146.4, 146.0, 133.9, 133.7, 131.8, 127.1, 126.9,
9
5-97 C; H NMR (500 MHz, CDCl3, ppm): δ 9.82 (s, 1H, D
exchangeable), 8.17 (d, J = 8Hz, 1H), 7.76 (s, 1H), 7.65 (t, J = 7.5 Hz,
H), 7.59 (s, 1H), 7.47 (d, J = 8.5 Hz, 1H), 7.37 (t, J = 7Hz, 1H), 7.30
d, J = 8.5 Hz, 1H), 7.16 (s, 1H), 7.12 (d, J = 8.5 Hz, 1H), 6.80 (d, J =
Hz, 1H), 5.73-5.65 (m, 1H), 5.13-5.08 (m, 2H), 2.66-2.62 (m, 2H),
2
O
1
4
C
25.8, 125.3, 124.3, 118.0, 116.5, 115.7, 113.3, 112.7, 105.5, 85.4,
1.0, 31.8, 27.2, 23.2, 22.5, 14.1. HRMS (ESI+): m/z calcd. for
1
(
+
27
H
26
N
2
NaO
4
[M+Na] : 465.1784, found: 465.1781.
8
1
1
1
4
1
4
1
3
.66 (s, 3H). C NMR (125 MHz, CDCl
, ppm): δ 178.2, 156.0, 155.5, Acknowledgements
52.5, 146.5, 146.1, 134.0, 132.0, 131.2, 127.1, 126.6, 125.9, 125.4, The authors wish to express their gratitude to the BRNS, India for
24.3, 121.8, 120.5, 118.1, 116.5, 115.7, 113.4, 112.8, 105.5, 84.3, financial support, DST, New Delhi for providing HRMS facility and
5.6, 26.3. FTIR (KBr, v = cm ): 3284, 1713, 1697, 1609, 1556, 1372, CSIR, New Delhi for awarding SRF to S.K. The reviewers are highly
303, 1236. HRMS (ESI+): m/z calcd. for C25
36.1155, found: 436.1142.
3
-1
+
H19NNaO
5
[M+Na] : acknowledged for their valuable comments.
6
-(2-(furan-2-yl)-4-oxo-4H-chromen-3-yl)-4-methyl-4-pentyl-1H-
Supplementary Material
1 13
benzo[d][1,3]oxazin-2(4H)-one (5c). Yield: 92% as brown solid, mp Characterization data H,
9
C NMR and HRMS spectra
o
1
6-99 C; H NMR (500 MHz, CDCl3, ppm): δ 9.69 (s, 1H, D O associated with this article are available.
2
exchangeable), 8.17 (d, J = 6.5 Hz, 1H), 7.64-7.59 (m, 2H), 7.46 (d, J
1
0 | J. Name., 2012, 00, 1-3
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Journal Name
PleaseRd So Cn oA t da vd aj un s ct ems argins
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DOI: 10.1039/C5RA15274G
ARTICLE
Organomet. Chem., 2009, 694, 446; (d) D. Srimani, A. Sarkar,
Tetrahedron Lett., 2008, 49, 6304; (e) J. Cui, M. Zhang, Y.
Zhang, Inorg. Chem. Commun., 2010, 13, 81; (f) Y.-C. Lai, H.-Y.
Chen, W.-C. Hung, C.-C. Lin, F.-E. Hong, Tetrahedron, 2005, 61,
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Page 12 of 12
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DOI: 10.1039/C5RA15274G
ARTICLE
Journal Name
A facile access to novel 1-oxa- and 1-aza-flavonyl-4-methyl-1H-benzo[d][1,3]oxazin-2(4H)-
ones using microwave assisted phosphine-free Suzuki coupling of bromo flavones with
boronic acids using a novel catalytic system (C) under aerobic condition is reported.
1
2 | J. Name., 2012, 00, 1-3
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