(Thio)etherification of Quinoxalinones under Visible-Light Photoredox Catalysis

Article abstract of DOI:10.1002/adsc.201901008

An efficient visible-light-induced (thio)etherification of quinoxalin-2(1H)-ones with divergent aliphatic alcohols and thiols (primary, secondary, and tertiary) at room temperature in air has been developed. This protocol was highlighted by its mild conditions, readily available starting materials, operational simplicity, and wide functional group tolerance. (Figure presented.).

Full text of DOI:10.1002/adsc.201901008

Title: (Thio)etherification of Quinoxalinones under Visible-Light
Photoredox Catalysis
Authors: Jiadi Zhou, Peng Zhou, Tingting Zhao, Quanlei Ren, and
Jianjun Li
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To be cited as: Adv. Synth. Catal. 10.1002/adsc.201901008
Link to VoR: http://dx.doi.org/10.1002/adsc.201901008

Advanced Synthesis & Catalysis
10.1002/adsc.201901008
FULL PAPER
DOI: 10.1002/adsc.201((will be filled in by the editorial staff))
(Thio)etherification of Quinoxalinones under Visible-Light
Photoredox Catalysis
a
b
b
b
a,b*
Jiadi Zhou, Peng Zhou, Tingting Zhao, Quanlei Ren, and Jianjun Li
a
Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of
Technology, Hangzhou 310014, P. R. of China.
College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. of China. E-mail:
lijianjun@zjut.edu.cn
b
Received: ((will be filled in by the editorial staff))
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201######.((Please
delete if not appropriate))
Abstract.
An
efficient
visible-light-induced
(
thio)etherification of quinoxalin-2(1H)-ones with divergent Keywords: Quinoxalin-2(1H)-ones; (Thio)etherification;
aliphatic alcohols and thiols (primary, secondary, and Visible-light-induced; Alcohols; Thiols
tertiary) at room temperature in air has been developed. This
protocol was highlighted by its mild conditions, readily
available starting materials, operational simplicity, and wide
functional group tolerance.
thioetherifications with aliphatic thiols were
rarely explored.
Quinoxalin-2(1H)-ones represent a valuable
The construction of the C−O and C-S bond has class of structural features that are extensively
long been a fundamentally important pursuit in utilized in synthetic chemistry, materials, and
the synthetic community. Over the years, typical pharmaceuticals (Figure 1).[ Recently, various
Introduction
9]
[
10]
methodologies for aryl (thio)etherification have
C3−H functionalization strategies
including
[
1]
[11]
[12]
[13]
been well established, such as the Cu-based,
arylation,
Pd-based, Fe-based and Ni-based coupling phosphonation,
reactions. However, the routine use of the difluoroarylmethylation,[
alkylation,
acylation,
[
2]
[3]
[4]
[14]
[15]
trifluoromethylation,
and amination
16]
[17]
of
prefunctionalized substrate precursors and often
harsh reaction conditions limits their potential
application. From a synthetic point of view, the
quinoxalin-2(1H)-ones have been reported. Very
[
18a]
recently, the oxidative C−H fluoroalkoxylation
or alkoxylation[
18b]
of quinoxalinones with
(
thio)etherification via cross-dehydrogenative alcohols has been reported, however, the method
coupling (CDC) represents one of the most
straightforward and efficient approaches for the
needs stoichiometric PhI(OTFA) . For a long
period of time, we have been focusing on the
2
2
construction of the C−O and C-S bond due to its C(sp )−H alkylation of various N
‑
Heteroarenes
pyridines,
and the C-O
Herein, we
high atom and step economy. Nevertheless, direct
(quinolines,
isoquinolins, [
19a]
C−H/O(S)−H (thio)etherification with aliphatic
benzooxazole and benzothiazole)
alcohols and thiols still remains challenging since bond construction by CDC.[
19b,19c]
many methods for their functionalizations lead to
describe a O
photocatalytic
2
-mediated CDC approach for
2
carbon−carbon bond formation adjacent to the
quinoxalinones
C(sp )-H
oxygen atom,[ and the thiols can be easily over- (thio)etherification by alcohols and thiols at room
oxidized to generate sulfoxides and sulfones. In temperature in moderate to good yields with high
the past few years, a few examples of aryl regioselectivity.
5]
[
6]
(
thio)etherification of simple arenes with
[
7]
[8]
alcohols
or aryl thiols
were successfully
demonstrated by the utilization of CDC strategy.
However, in most C−H/O−H etherifications,
metal catalysts and stoichiometric chemical
oxidants were used, and the direct C−H/S−H
1
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
Table 1. Optimization of photocatalytic etherification a
Photocatalyst
mol %)
Ru(bpy) Cl
Ir(ppy) (5)
Rose bengal (5)
Eosin Y (5)
Methylene blue (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (1)
Rhodamine 6G (10)
Additive
(equiv.)
Yield
(%)b
21
/
25
32
/
42
11
/
15
81
46
44
69
80
30
72
71
30
37
/
Entry
(
Figure 1. (Thio)ether substituted quinoxalinone
derivatives
1
2
3
4
5
6
7
8
9
3
3
(5)
3
Cs
NaOH (2)
CO (2)
CO
SO
SO
2
CO
3
(2)
K
2
3
1
1
1
1
1
1
1
1
0
1
2
3
4
5
6
7
CF
CF
3
2
H (2)
H (2)
3
3
H
2
4
(2)
CF
3
3
3
3
3
3
3
3
3
CO
CO
CO
CO
CO
CO
CO
CO
CO
2
2
2
2
2
2
2
2
2
H (2)
H (2)
H (2)
H (3)
H (1)
H (2)
H (2)
H (2)
H (2)
CF
CF
CF
CF
CF
CF
CF
CF
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
Rhodamine 6G (5)
c
1
8
d
e
1
9
2
0
f
2
1
80
a
Reaction conditions: 1a (0.4 mmol), 2a (1 mL),
photocatalyst, additive, 3 W Blue LED, air, rt;
b
Isolated yields based on 1a.
c
3
3
W white LEDs.
W green LEDs.
d
e
f
Without light irradiation.
was used.
O
2
(
Table 1, entries 7-12). The CF
3
CO H may
2
protonate 1a, thus facilitating the subsequent
nucleophilic substitution. Further optimization of
the reaction was carried out by screening of the
Scheme 1. The construction of the C−O and C-S bond
loading amounts of Rhodamine 6G and CF
3
CO H.
2
However, the yield has no significant
improvement (Table 1, entries 13-17).
Unexpectedly, when the reaction was carried out
in the absence of Rhodamine 6G, 3aa was
obtained in 30% yield. In addition, when the
reaction was conducted under irradiation with 3
W white and green LED lamps, 3aa was also
obtained in 30% and 37% yield, respectively
Results and Discussion
Initially, 1-methylquinoxalin-2(1H)-one (1a) was
treated with isopropyl alcohol (2a) in the
presence of Ru(bpy)
3
Cl
3
(5 mol %) under
irradiation with 3 W blue LED lamps. To our
(
Table 1, entries 18 and 19). No transformation
delight, the desired product 3aa was obtained in
was observed when the reaction was carried out
in the dark (Table 1, entry 20). Moreover, when
2
1% yield after 24 h (Table 1, entry 1).
Furthermore, other photocatalysts such as
Ir(ppy) , Rose bengal, Eosin Y, Methylene blue,
the reaction was carried out under O
has no significant improvement (Table 1, entry
1).
2
, the yield
3
and Rhodamine 6G were also examined (Table 1,
entries 2-6). Rhodamine 6G was demonstrated to
be the most effective one to give the desired
product 3aa in 42% yield (Table 1, entry 6). We
next screened different bases and acids aiming to
2
With the optimized reaction conditions in hand, the
scope of the present transformation was further
investigated by employing various quinoxalin-2-one
derivatives and alcohols (Scheme 2). Firstly, a series
improve the yield, the application of CF
3
COOH
(2.0 equiv.) could improve the yield to 81%
2
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
of alcohols were attempted under the standard
conditions. Simple aliphatic alcohols, such as
isopropyl alcohol, ethanol, butyl alcohol, 2-
methylpropan-1-ol,
3-methylbutan-1-ol,
and
cyclopentanol were all compatible with the reaction
to give the desired products in 61-85% yields (3aa,
3
ab, 3ac, 3ad, 3ae, and 3af). Importantly, the use of
glycol ethers as starting materials did not compromise
the efficiency of the cross-coupling (3ag). Moreover,
2
,2,2-trifluoroethan-1-ol were also found to
participate efficiently in the reactions (3ah). Enyl
group was also tolerated, the corresponding product
3ai was obtained. Nevertheless, none of desired
product was detected when phenol were employed in
the present reaction system. Notably, N-free protected
quinoxalin-2(1H)-ones also worked well (3ca, 3cc,
and 3ce). The compatibility with N-substituted
quinoxalinones was then examined. Various N-
protected groups such as N-ethyl, N-benzyl, N-phenyl,
N-esteryl, N-propynyl, and N-octyl groups were all
well tolerated in this reaction system to give the
desired products in 54-88% yields (3ba, 3bb, 3bc,
3
bd, 3db, 3eb, 3fb, 3gb, and 3hb). Furthermore, a
broad tolerance of substituted quinoxalin-2(1H)-ones
with an electron-withdrawing or electron-donating
group, such as F, Cl, Br, NO
2
, CO
2
Me, CF , CN, and
3
Me at 6 or 7-position of the aromatic rings, reacted
with ethanol smoothly to generate the anticipated
products (3ib, 3jb, 3kb, 3lb, 3mb, 3nb, 3ob, 3sb, 3tb,
3
ub) in moderate to good yields. A mixture of 6-
MeO and 7-MeO substituted quinoxalin-2(1H)-ones
reacted with ethanol gave the products (3rb and 3rb’)
in 64 % yields. A substituted quinoxalin-2(1H)-one
with Cl or Br on the 8-position was also the suitable
substrate, giving the desired product (3pb and 3qb) in
87% and 80% yield, respectively.
Scheme 2. Scope of photocatalytic etherification a
a
Reaction conditions: 1 (0.4 mmol), 2 (1 mL), Rhodamine
6
G (5 mol %), CF
3
COOH (0.8 mmol), 3 W Blue LEDs, air,
rt, 24 h; isolated yields based on 1.
b
3
Phenol (3 equiv.) and CH CN (1 mL) was used.
3
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
groups on the benzene ring were also investigated
under the optimal reaction conditions, and the
corresponding products (5bk, 5fc, 5ck, 5ek, 5gc, 5ic,
5
jc, and 5kc) were isolated in moderate to good
yields. The reaction also processed smoothly with
disubstituted quinoxalin-2(1H)-ones as the substrates,
giving the corresponding products 5dc and 5hc in 48%
and 84% yield, respectively.
Further application for such synthetic methodology
was carried out. For example, a simple ester
hydrolysis of 3fb delivered the corresponding aldose
reductase (ALR2) inhibitor (6fb) in good yield
(
Scheme 4).
Scheme 4. Synthesis of 6fb
Scheme 5. Control experiment
Scheme 3. Scope of photocatalytic thioetherification a
a
Reaction conditions: 1a (0.4 mmol), 4 (1 mL),
Some preliminary mechanistic studies were
conducted. When radical scavenger 2,2,6,6-
tetramethyl-1-piperidinyloxy (TEMPO) or 2,6-di-
tert-butyl-4methylphenol (BHT) was added into the
reaction system under the standard conditions, the
present transformation was completely inhibited,
suggesting that this transformation might involve a
radical process (Scheme 5a). Moreover, when the
Rhodamine 6G (5 mol %), CF
3
COOH (0.8 mmol), 3 W
Blue LEDs, air, rt, 24 h; isolated yields based on 1a.
b
p-Toluenethiol (3 equiv.) and CH
the yield based on p-toluenethiol.
3
CN (1 mL) was used,
We further examined the scope of this
quinoxalinones thioetherification by employing
various thiols (Scheme 3). Simple aliphatic thiols
reaction was carried out under N , no product was
2
(
primary, secondary, and tertiary) such as ethanethiol,
detected. This result indicates that dioxygen is
essential for the present transformation (Scheme 5b).
propane-2-thiol, 2-methylpropane-2-thiol, and
cyclopentanethiol were suitable substrates, and the
corresponding products were obtained in 74-84 yields
•−
In order to verify the formation of O
photoredox catalysis, 5,5-dimethyl-pyrroline-N-oxide
DMPO) was employed as a capture reagent to trap
2
radical under
(
5aa, 5ab, 5ac, and 5ad). In addition, various primary
(
aliphatic thiols containing a long aliphatic chains or
aromatic ring group were also suitable substrates, and
the corresponding products (5ae, 5af, and 5ag) were
obtained in 55-92% yields. Ethyl 2-mercaptoacetate
bearing an ester group was also an efficient substrate
in this transformation, giving 5ah in 82% yield.
Notably, when ethane-1,2-dithiol bearing two
hydrosulfuryl groups was used, only one of them
could be coupled to 1a, giving 5ai in 41% yield. Enyl
group was also tolerated, the corresponding product
the possible radical in this reaction by electron
paramagnetic resonance (EPR), which was presented
in Figures 6 and 7 of ESI†. When DMPO was added
into a solution of 1a, TFA, and Rhodamine 6G in air
saturated ethanol or 1-propanethiol, the strong
•
−
characteristic signal of an O
emerged after the reaction mixture was irradiated by
W blue LED lamps after 15 min. To our delight,
when in the absence of Rhodamine 6G, the
2
adduct with DMPO
3
•−
characteristic signal of an O
2
adduct with DMPO
5
aj was obtained. However, when p-toluenethiol was
employed, only trace product was detected, along
with 13% yield of S-(p-tolyl) 4-
methylbenzenesulfonothioate. Moreover, quinoxalin-
(1H)-ones bearing CF , Me, F, Cl, CN, and CO Me
was also observed. These experimental results clearly
revealed that two radical routes were involved in the
reaction.
2
3
2
4
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
Cyclic voltammetry measurements were also Conclusion
performed to understand the possible mechanism. As
shown in Figure 8 of ESI†, the oxidation semi-peak
In summary, we have illustrated the visible-light-
potential of 1a (Ep/2= 1.83 V vs SCE in CH CN) and
3
2
promoted
quinoxalinones
C(sp )-H
1
-propanethiol (Ep/2= 1.54 V vs SCE in CH
3
CN)
(
air.
thio)etherification with diverse alcohols and thiols in
were both higher than that of Rhodamine 6G* (Ered
=
[25]
.95 V vs SCE).[
23]
The present protocol provides a facile and
0
Meanwhile, high-energy alkoxy
practical approach to access diverse 3-alkyloxyl and
3-alkylthiol substituted quinoxalin-2(1H)-ones in
moderate to good yields, which is of great value from
organic synthesis perspectives due to its desirable
features including a cheap catalyst, eco-friendly
energy source, high atom economy, operation
radicals from simple alkanols (Ep/2 > 2.0 V vs SCE in
CH
CN) is very difficult.[
20]
3
We infer that 1a might
be irradiated by light to produce the excited-state 1a*
p/2= −1.36 V vs SCE in CH CN based on the
(
E
3
electrochemical and spectroscopic measurements, see
ESI† for details),[
Rhodamine 6G* or O (ERed = −0.44 V vs. SCE).
24]
which would be oxidized by
[21]
simplicity, and mild conditions.
A
detailed
2
investigation of the mechanism and further
application of this protocol is underway in our
laboratory.
The Stern−Volmer plot reveals the effective
quenching of Rhodamine 6G* by 1-
methylquinoxalin-2(1H)-one (1a*) which indicates
the single electron transfer (SET) step and reductive Experimental Section
quenching cycle of the cross-coupling process
(
Figures 1 and 3 in ESI†). On the other hand, 1a*
General Considerations
also can be quenched by Rhodamine 6G* effectively
Figures 4 and 5 in ESI†). In contrast, the emission
intensity of Rhodamine 6G* has no dramatically
change along with the increasing of the amount of 1-
propanethiol (Figures 2 and 3 in ESI†).
All purchased chemicals were used as received without
further purification. All reactions were monitored by TLC
(
1
with silica gel-coated plates. H (400, 500, or 600 MHz)
NMR and 13C (101, 126, or 151 MHz) NMR spectra were
3 6
recorded on a Varian spectrometer in CDCl or DMSO-d
using tetramethylsilane (TMS) as internal standards. Data
are reported as follows: Chemical shift (number of protons,
multiplicity, coupling constants). Coupling constants were
quoted to the nearest 0.1 Hz and multiplicity reported
according to the following convention: s = singlet, d =
doublet, t = triplet, q = quartet, m = multiplet, hept = heptet,
br = broad. Mass spectra were measured with a HRMS-
APCI instrument using ESI ionization. Fourier transform
infrared spectroscopy (FTIR) spectra were recorded on a
Nicolet iS50 in attenuated total reflectance (ATR) mode
On the basis of these results and relevant reports,[18,
2]
2
a possible mechanism was proposed in Scheme 6.
Initially, 1a is irradiated by light to produce the
excited-state 1a*, which would be oxidized by
Rhodamine 6G* (path a) or O
2
(path b) to produce
reactive radical cation A. Subsequently, the oxidation
•−
[23]
of Rhodamine 6G (Eox= −1.14 V vs Ag/AgCl) by
•−
O
2
generates the ground state Rhodamine 6G and O .
2
Then, A is trapped by alcohols or thiols to form
nitrogen radical intermediate B. Finally, B is oxidized
-1
and reported with wave number (cm ). The cyclic
voltammetry measurements were detected by using a CHI
by O
2
or HO
2
• to give the CDC product after
was
6
00E
quenching experiments were performed on a Hitachi F-
000 FL Spectrophotometer. The EPR experiments were
electrochemical
workstation.
Fluorescence
deprotonation. In addition, the formation of H
2
O
2
also examined by a starch potassium iodide test paper
and the paper was changed into blue.
7
performed on Bruker A300 EPR Spectrometer. UV-visable
absorption experiments were performed on UV-2250
spectrophotometer.
General procedure for the synthesis of compounds in
Scheme 2
To a 25 mL dried Schlenk tube equipped with magnetic
stir bar was added 1 (0.4 mmol), Rhodamine 6G (0.02
mmol, 5 mol%), alcohols (1 mL), CF COOH (0.8 mmol, 2
3
equiv.). The mixture was stirred at room temperature and
irradiated by 3 W blue LEDs for 24 h, the reaction mixture
was quenched with satd. aq. NaHCO
extracted with EtOAc. The combined organic layer was
dried over anhydrous Na SO and concentrated under
3
(10 mL) and
2
4
reduced pressure. The crude products were purified on a
silica gel column using hexane/EtOAc.
General procedure for the synthesis of compounds in
Scheme 3
Scheme 6. Possible reaction pathway
To a 25 mL dried Schlenk tube equipped with magnetic
stir bar was added 1 (0.4 mmol), Rhodamine 6G (0.02
mmol, 5 mol%), thiols (1 mL), CF COOH (0.8 mmol, 2
3
equiv.). The mixture was stirred at room temperature and
5
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
irradiated by 3W blue LEDs for 24 h, the reaction mixture
(3ag) 3-(2-methoxyethoxy)-1-methylquinoxalin-2(1H)-
was quenched with satd. aq. NaHCO
extracted with EtOAc. The combined organic layer was
dried over anhydrous Na SO and concentrated under
reduced pressure. The crude products were purified on a
silica gel column using hexane/EtOAc.
3
(10 mL) and
one
1
3
H NMR (400 MHz, CDCl ) δ 7.62 (dd, J = 7.9, 1.5 Hz,
1H), 7.44 – 7.40 (m, 1H), 7.73 7.25 (m, 2H), 4.64 (t, J =
9.6 Hz, 2H), 3.85 (t, J = 10 Hz, 2H), 3.72 (s, 3H), 3.44 (s,
2
4
13
3H); C NMR (101 MHz, CDCl
3
) δ 153.9, 151.1, 131.8,
Characterization data for the products
131.1, 127.7, 127.3, 124.1, 113.8, 70.3, 66.4, 59.3, 29.6;
-
1
(
3aa) 3-isopropoxy-1-methylquinoxalin-2(1H)-one
ATR-FTIR (cm ):2925, 1644, 1456, 1313, 1279, 1173,
1
[M+Na]+
14 2 3
H N NaO
H NMR (400 MHz, CDCl
3
) δ 7.61 (dd, J = 7.9, 1.4 Hz,
H), 7.44-7.38 (m, 1H), 7.30 (dd, J = 7.7, 1.1 Hz, 1H),
.25 (dd, J = 8.3, 1.0 Hz, 1H), 5.49 (hept, J = 6.2 Hz, 1H),
1077, 732; HRMS (ESI): C12
calculated: 257.0897, found: 257.0894.
(3ah) 1-methyl-3-(2,2,2-trifluoroethoxy)quinoxalin-
.72 (s, 3H), 1.46 (d, J = 6.2 Hz, 6H); C NMR (101 MHz, 2(1H)-one
) δ 153.4, 151.4, 131.4, 131.3, 127.4, 126.7, 123.8,
1H NMR (500 MHz, CDCl
13.5, 70.5, 29.5, 21.6 (2C); HRMS (ESI): C12 1H), 7.51 – 7.45 (m, 1H), 7.36 – 7.32 (m, 1H), 7.30 (d, J =
1
7
3
1
3
CDCl
3
3
) δ 7.65 (dd, J = 8.0, 1.4 Hz,
1
15 2 2
H N O
+
13
[
M+H] calculated: 219.1128, found: 219.1153.
7.6 Hz, 1H), 4.90 (q, J = 8.3 Hz, 2H), 3.74 (s, 3H);
NMR (101 MHz, CDCl ) δ 152.0, 150.2, 132.1, 130.0,
128.2, 127.9, 124.2, 123.1 (q, J = 276 Hz), 113.8, 62.8 (q,
= 37 Hz), 29.6; HRMS (ESI): C11 NaO
[M+Na]+
calculated: 281.0508, found: 281.0537.
C
(
3ab) 3-ethoxy-1-methylquinoxalin-2(1H)-one
3
1
H NMR (500 MHz, CDCl
1
8
3
) δ 7.63 (dd, J = 7.9, 1.3 Hz,
H), 7.44 – 7.39 (m, 1H), 7.33 – 7.29 (m, 1H), 7.26 (d, J =
.1 Hz,1H), 4.56 (q, J = 7.1 Hz, 2H), 3.73 (s, 3H), 1.51 (t,
F
J
F
H
9 3
F N
2
2
1
3
J = 7.1 Hz, 3H); C NMR (126 MHz, CDCl
3
) δ 153.9,
(3ai)
3-(but-3-en-1-yloxy)-1-methylquinoxalin-2(1H)-
1
1
2
51.2, 131.5, 131.2, 127.5, 126.9, 123.9, 113.6, 63.5, 29.5,
one
+
1
4.2; HRMS (ESI): C11
H
12
N
2
NaO
2
[M+Na] calculated:
H NMR (400 MHz, CDCl ) δ 7.63 (d, J = 7.9 Hz, 1H),
3
27.0791, found: 227.0813.
7.41 (t, J = 7.8 Hz, 1H), 7.32 – 7.24 (m, 2H), 5.97 (ddt, J =
17.1, 10.3, 6.8 Hz, 1H), 5.19 (dd, J = 17.2, 1.6 Hz, 1H),
5.11 (dd, J = 10.4, 1.2 Hz, 1H), 4.53 (t, J = 7.1 Hz, 2H),
3.72 (s, 3H), 2.66 (q, J = 7.0 Hz, 2H); 13C NMR (101 MHz,
(
3ac) 3-butoxy-1-methylquinoxalin-2(1H)-one
1
H NMR (500 MHz, CDCl
3
) δ 7.62 (dd, J = 7.9, 1.3 Hz,
1
8
1
H), 7.43 – 7.38 (m, 1H), 7.32 – 7.28 (m, 1H), 7.26 (d, J =
.4 Hz, 1H), 4.48 (t, J = 6.8 Hz, 2H), 3.72 (s, 3H), 1.91 –
.85 (m, 2H), 1.56 – 1.48 (m, 2H), 0.99 (t, J = 7.4 Hz, 3H);
CDCl
3
) δ 153.8, 151.1, 134.0, 131.6, 131.1, 127.6, 127.0,
123.9, 117.3, 113.6, 66.6, 32.9, 29.5; HRMS (ESI):
13
+
C NMR (125 MHz, CDCl
3
) δ 154.1, 151.2, 131.6, 131.3,
C
13
H
14
N
2
NaO
253.0948.
(3ba) 1-Ethyl-3-isopropoxyquinoxalin-2(1H)-one
2
[M+Na] calculated: 253.0947, found:
1
27.5, 126.9, 123.9, 113.6, 67.4, 30.5, 29.5, 19.2, 13.8;
+
HRMS (ESI):
55.1104, found: 255.1121.
3ad) 3-Isobutoxy-1-methylquinoxalin-2(1H)-one
C
13
H
16
N
2
NaO
2
[M+Na]
calculated:
1
2
(
3
H NMR (400 MHz, CDCl ) δ 7.62 (dd, J = 8.2, 1.5 Hz,
1H), 7.42 – 7.36 (m, 1H), 7.31 – 7.27 (m, 2H), 5.48 (hept,
J = 6.2 Hz, 1H), 4.34 (q, J = 7.2 Hz, 2H), 1.47 (d, J = 6.2
Hz, 6H), 1.38 (t, J = 7.2 Hz, 3H); 13C NMR (101 MHz,
CDCl ) δ 153.4, 150.8, 131.7, 130.3, 127.7, 126.7, 123.6,
3
113.4, 70.4, 37.6, 21.6 (2C), 12.4; ATR-FTIR (cm ):2979,
1670, 1489, 1470, 1314, 1262, 1125; HRMS (ESI):
1
H NMR (400 MHz, CDCl
3
) δ 7.62 (dd, J = 7.9, 1.4 Hz,
H), 7.43 – 7.37 (m, 1H), 7.32 – 7.27 (m, 1H), 7.25 (d, J =
.3 Hz, 1H), 4.24 (d, J = 6.9 Hz, 2H), 3.72 (s, 3H), 3.32 –
1
8
2
1
3
-1
.22 (m, 1H), 1.06 (d, J = 6.7 Hz, 6H); C NMR (100
MHz, CDCl
1
C
2
3
) δ 154.2, 151.1, 131.5, 131.2, 127.4, 126.9,
23.9, 113.6, 73.7, 29.4, 27.6, 19.3; HRMS (ESI):
C
13
H
16
N
2
NaO
255.1126.
(3bb) 3-Ethoxy-1-ethylquinoxalin-2(1H)-one
[M+Na]+ calculated: 255.1104, found:
2
+
13
H
16
N
2
2
NaO [M+Na] calculated: 255.1104, found:
55.1128.
1
(
3ae) 3-(isopentyloxy)-1-methylquinoxalin-2(1H)-one
3
H NMR (400 MHz, CDCl ) δ 7.66 – 7.61 (m, 1H), 7.44 –
1
H NMR (400 MHz, CDCl
3
) δ 7.63 (dd, J = 7.9, 1.4 Hz,
7.37 (m, 1H), 7.32 – 7.25 (m, 2H), 4.55 (q, J = 7.1 Hz, 2H),
4.35 (q, J = 7.2 Hz, 2H), 1.51 (t, J = 7.1 Hz, 3H), 1.38 (t, J
= 7.2 Hz, 3H); C NMR (101 MHz, CDCl
1
=
H), 7.43 – 7.37 (m, 1H), 7.32 – 7.27 (m, 1H), 7.25 (dd, J
8.3, 1.1 Hz, 1H), 4.51 (t, J = 6.8 Hz, 2H), 3.72 (s, 3H),
13
3
) δ 153.9, 150.7,
1
6
1
2
1
.90 – 1.83 (m, 1H), 1.78 (q, J = 6.9 Hz, 2H), 0.99 (d, J =
131.6, 130.4, 127.8, 126.9, 123.7, 113.5, 63.5, 37.6, 14.2,
.4 Hz, 6H); 1 C NMR (100 MHz, CDCl
3
12.4; HRMS (ESI): C12
241.0947, found: 241.0965.
5.1, 22.6 (2C); ATR-FTIR (cm ):2958, 1671, 1473, 1387， (3bc) 3-Butoxy-1-ethylquinoxalin-2(1H)-one
+
3
) δ 154.1, 151.2,
14 2 2
H N NaO [M+Na] calculated:
31.5, 131.2, 127.5, 126.9, 123.9, 113.6, 66.2, 37.2, 29.5,
-
1
[M+Na]+
1
258, 1122, 751; HRMS (ESI): C14
H
18
N
2
NaO
2
H NMR (400 MHz, CDCl
3
) δ 7.64 (dd, J = 8.2, 1.5 Hz,
calculated: 269.1260, found: 269.1278.
1H), 7.42 – 7.37 (m, 1H), 7.31 – 7.26 (m, 2H), 4.47 (t, J =
6
1
7
.8 Hz, 2H), 4.34 (q, J = 7.2 Hz, 2H), 1.92 – 1.85 (m, 2H),
.58 – 1.48 (m, 2H), 1.38 (t, J = 7.2 Hz, 3H), 0.99 (t, J =
(
3af) 3-(cyclopentyloxy)-1-methylquinoxalin-2(1H)-one
1
H NMR (500 MHz, CDCl
3
) δ 7.62 (dd, J = 7.9, 1.4 Hz,
.4 Hz, 3H); 13C NMR (101 MHz, CDCl
3
) δ 154.1, 150.6,
1
=
–
1
1
3
H), 7.41 – 7.36 (m, 1H), 7.30 – 7.27 (m, 1H), 7.24 (dd, J
8.3, 1.0 Hz, 1H), 5.58 – 5.53 (m, 1H), 3.70 (s, 3H), 2.11
2.03 (m, 2H), 1.98 –1.92 (m, 2H), 1.88 –1.85 (m, 2H),
131.6, 130.4, 127.8, 126.9, 123.7, 113.5, 67.4, 37.6, 30.6,
19.2, 13.9, 12.4; ATR-FTIR (cm ): 2959, 1671, 1470,
1376, 1220, 1125, 1063, 753; HRMS (ESI): C14 NaO
2
-
1
1
3
.66 –1.63 (m, 2H); C NMR (126 MHz, CDCl
51.3, 131.5, 131.4, 127.5, 126.7, 123.8, 113.5, 79.9, 38.8,
2.6, 29.4, 25.0, 24.0; HRMS (ESI): C14 NaO
2
3
) δ 153.8,
H
18
N
2
+
[M+Na] calculated: 269.1260, found: 269.1278.
H
18
N
2
(3bd) 1-Ethyl-3-isobutoxyquinoxalin-2(1H)-one
+
1
[
M+Na] calculated: 267.1104, found: 267.1118.
3
H NMR (400 MHz, CDCl ) δ 7.65 (dd, J = 8.2, 1.5 Hz,
1
7
H), 7.45 – 7.40 (m, 1H), 7.34 – 7.29 (m, 2H), 4.36 (q, J =
.2 Hz, 2H), 4.23 (d, J = 6.8 Hz, 2H), 1.40 (t, J = 7.2 Hz,
6
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
3
H), 1.06 (d, J = 6.7 Hz, 6H); 13C NMR (101 MHz, CDCl
δ 153.9, 150.9, 131.8, 130.0, 127.8, 127.0, 124.1, 113.6,
3.8, 37.9, 27.6, 19.3 (2C), 12.4; ATR-FTIR (cm ):2925,
3
)
(3gb) 3-ethoxy-1-(prop-2-yn-1-yl)quinoxalin-2(1H)-one
H NMR (400 MHz, CDCl ) δ 7.64 (d, J = 8.0 Hz, 1H),
3
1
-
1
7
1
7.47 – 7.42 (m, 2H), 7.32 (ddd, J = 8.3, 6.2, 2.4 Hz, 1H),
5.07 (d, J = 2.4 Hz, 2H), 4.55 (q, J = 7.1 Hz, 2H), 2.28 (t, J
698, 1434, 1392, 1259, 1163, 1087; HRMS (ESI):
+
13
C
2
(
14
H
18
N
2
NaO
69.1279.
3ca) 3-isopropoxyquinoxalin-2(1H)-one
2
[M+Na] calculated: 269.1260, found:
= 2.5 Hz, 1H), 1.50 (t, J = 7.1 Hz, 3H); C NMR (101
MHz, DMSO-d
127.4, 124.5, 115.3, 78.4, 75.6, 63.5, 32.0, 14.5; HRMS
(ESI): C13 NaO
[M+Na]+ calculated: 251.0791,
found:251.0807.
(3hb) 3-ethoxy-1-octylquinoxalin-2(1H)-one
6
) δ 153.9, 149.9, 131.0, 130.4, 127.5,
1
H NMR (400 MHz, CDCl
3
) δ 12.23 (s, 1H), 7.60 (dd, J =
.9, 1.3 Hz, 1H), 7.42 – 7.38 (m, 1H), 7.37 – 7.27 (m, 2H),
.53 (hept, J = 6.2 Hz, 1H), 1.50 (d, J = 6.2 Hz, 6H); 13
) δ 153.7, 153.0, 131.5, 129.0,
26.8, 126.6, 124.3, 115.8, 70.8, 21.6 (2C); ATR-FTIR
H
12
N
2
2
7
5
C
1
NMR (101 MHz, CDCl
1
3
3
H NMR (400 MHz, CDCl ) δ 7.65 – 7.59 (m, 1H), 7.42 –
7.35 (m, 1H), 7.30 – 7.24 (m, 2H), 4.53 (q, J = 7.1 Hz, 2H),
4.26 (t, J = 7.6 Hz, 2H), 1.75 (quint, J = 7.6 Hz, 2H), 1.50
(t, J = 7.1 Hz, 3H), 1.40 – 1.20 (m, 10H), 0.87 (t, J = 6.8
-
1
(
cm ):2975, 1678, 1460, 1383, 1232, 1109; HRMS (ESI):
+
C
2
(
11
H
12
N
2
NaO
27.0812.
3cc) 3-butoxyquinoxalin-2(1H)-one
2
[M+Na] calculated: 227.0791, found:
Hz, 3H); 13C NMR (101 MHz, CDCl
3
) δ 153.9, 150.9,
131.6, 130.7, 127.8, 126.8, 123.7, 113.7, 63.4, 42.6, 31.8,
1
-1
H NMR (400 MHz, CDCl
m, 1H), 7.38 – 7.32 (m, 1H), 7.30 (d, J = 6.9 Hz, 1H),
.53 (t, J = 6.6 Hz, 2H), 1.97 – 1.84 (m, 2H), 1.60 – 1.53
3
) δ 12.37 (br, 1H), 7.46 – 7.38
29.3, 29.2, 27.2, 26.9, 22.6, 14.2, 14.1; ATR-FTIR (cm ):
(
2927, 2855, 1674, 1610, 1470, 1369, 1277, 1126, 1061,
4
(
752; HRMS (ESI): C18
303.2067, found:303.2061.
H
27
N
2
O
2
[M+H]+ calculated:
m, 2H), 1.01 (t, J = 7.2 Hz, 3H); 1 C NMR (101 MHz,
CDCl ) δ 154.4, 152.8, 131.4, 129.2, 127.0, 126.6, 124.4,
15.9, 67.6, 30.6, 19.3, 13.9; HRMS (ESI): C12 NaO
3
3
(3ib) 7-bromo-3-ethoxy-1-methylquinoxalin-2(1H)-one
1
1
H
14
N
2
2
3
H NMR (400 MHz, CDCl ) δ 7.78 (d, J = 2.1 Hz, 1H),
+
[
M+Na] calculated: 241.0947, found: 241.0961.
7.49 (dd, J = 8.8, 2.2 Hz, 1H), 7.11 (d, J = 8.8 Hz, 1H),
(
3ce) 3-(isopentyloxy)quinoxalin-2(1H)-one
4.54 (q, J = 7.0 Hz, 2H), 3.69 (s, 3H), 1.49 (t, J = 7.0 Hz,
1
13
H NMR (400 MHz, CDCl
3
) δ 12.34 (s, 1H), 7.62 (d, J = 7.
3H); C NMR (151 MHz, CDCl
3
) δ 154.5, 150.9, 132.4,
7
9
Hz, 1H), 7.48 – 7.28 (m, 3H), 4.55 (t, J = 6.6 Hz, 2H), 1.
130.7, 130.0, 129.6, 116.5, 114.9, 63.8, 29.6, 14.1; HRMS
(ESI): C11 NaO
[M+Na]+ calculated: 304.9896,
found: 304.9919.
(3jb) 6-bromo-3-ethoxy-1-methylquinoxalin-2(1H)-one
1
3
0 – 1.79 (m, 3H), 1.00 (d, J = 6.0 Hz, 6H); C NMR (101
) δ 154.4, 152.8, 131.4, 129.2, 127.0, 126.6, 1
H
11BrN
2
2
MHz, CDCl
4.5, 115.9, 66.4, 37.2, 25.1, 22.6 (2C); ATR-FTIR (cm ):
959, 1671, 1495, 1379, 1321, 1272, 1123, 1050; HRMS (
3
-
1
2
2
1
H NMR (400 MHz, CDCl
[M+Na] calculated: 255.1104, found: 7.36 (m, 2H), 4.52 (q, J = 7.1 Hz, 2H), 3.68 (s, 3H), 1.49 (t,
J = 7.1 Hz, 3H); 13C NMR (101 MHz, CDCl
) δ 154.1,
150.9, 132.7, 130.3, 128.8, 127.1, 120.3, 116.7, 63.8, 29.7,
3
) δ 7.47 – 7.44 (m, 1H), 7.40 –
+
ESI): C13
55.1130.
3db) 1-benzyl-3-ethoxyquinoxalin-2(1H)-one
16 2 2
H N NaO
2
(
3
1
+
H NMR (400 MHz, CDCl
3
) δ 7.62 (dd, J = 7.4, 1.9 Hz,
14.2; HRMS (ESI): C11
2 2
H11BrN NaO [M+Na] calculated:
1
2
H), 7.34 – 7.17 (m, 8H), 5.52 (s, 2H), 4.58 (q, J = 7.1 Hz,
304.9896, found: 304.9887.
(3kb) 6,7-dichloro-3-ethoxy-1-methylquinoxalin-2(1H)-
1
3
H), 1.53 (t, J = 7.1 Hz, 3H); C NMR (101 MHz, CDCl
3
)
δ 154.0, 151.4, 135.2, 131.5, 130.8, 128.9 (2C), 127.7,
27.6, 127.0 (2C), 126.9, 123.9, 114.5, 63.6, 46.2, 14.2;
one
1
1
3
H NMR (400 MHz, CDCl ) δ 7.69 (s, 1H), 7.32 (s, 1H),
+
HRMS (ESI): C17
H
17
N
2
O
2
[M+H] calculated: 281.1285,
4.52 (q, J = 7.1 Hz, 2H), 3.67 (s, 3H), 1.49 (t, J = 7.1 Hz,
3H); 13C NMR (101 MHz, CDCl
) δ 154.5, 150.6, 131.0,
130.6, 130.5, 128.3, 127.5, 115.0, 64.0, 29.8, 14.1; HRMS
(ESI): C11
found: 295.0028.
found: 281.1304.
3
(
3eb) 3-ethoxy-1-phenethylquinoxalin-2(1H)-one
1
+
H NMR (400 MHz, CDCl
3
) δ 7.65 (dd, J = 8.2, 1.5 Hz,
H), 7.43 – 7.37 (m, 1H), 7.34 (d, J = 4.8 Hz, 4H), 7.32 –
.27 (m, 3H), 4.55 (q, J = 7.1 Hz, 2H), 4.50 – 4.41 (m, 2H), (3lb) 3-ethoxy-1-methyl-6-nitroquinoxalin-2(1H)-one
2 2 2
H10Cl N NaO [M+Na] calculated: 295.0012,
1
7
3
.07 – 3.01 (m, 2H), 1.51 (t, J = 7.1 Hz, 3H); 13C NMR
) δ 154.0, 150.9, 137.9, 131.7, 130.6,
28.9 (2C), 128.9 (2C), 128.0, 127.1, 127.0, 124.0, 113.5,
1
3
H NMR (400 MHz, CDCl ) δ 8.49 (d, J = 2.1 Hz, 1H), 8.2
(
101 MHz, CDCl
3
6 (dd, J = 9.1, 2.4 Hz, 1H), 7.36 (d, J = 9.1 Hz, 1H), 4.59 (
1
6
1
q, J = 7.1 Hz, 2H), 3.78 (s, 3H), 1.52 (t, J = 7.1 Hz, 3H); 13
-
1
3.6, 44.1, 33.4, 14.3; ATR-FTIR (cm ): 2975, 1667, 1609, C NMR (151 MHz, CDCl
3
) δ 155.1, 150.8, 143.8, 136.3, 1
491, 1339, 1237, 1128, 745, 702; HRMS (ESI): 31.1, 123.0, 121.7, 114.0, 64.4, 30.1, 14.l; HRMS (ESI): C
+
+
C
18
H
19
N
2
O
2
[M+H] calculated: 295.1441, found:
11
H
12
N
3
O
4
[M+H] calculated: 250.0822, found: 250.0816.
2
95.1443.
(3mb) 3-ethoxy-1,6,7-trimethylquinoxalin-2(1H)-one
1
(
3fb) tert-butyl 2-(3-ethoxy-2-oxoquinoxalin-1(2H)-
H NMR (400 MHz, CDCl
3
) δ 7.39 (s, 1H), 7.01 (s, 1H),
yl)acetate
H NMR (400 MHz, CDCl
4.51 (q, J = 7.1 Hz, 2H), 3.69 (s, 3H), 2.38 (s, 3H), 2.32 (s,
1
13
3
) δ 7.63 (dd, J = 7.9, 1.3 Hz,
3H), 1.49 (t, J = 7.1 Hz, 3H); C NMR (151 MHz, CDCl
δ 153.5, 151.2, 136.1, 132.6, 129.4, 129.2, 127.8, 114.3,
63.2, 29.4, 20.2, 19.2, 14.2; HRMS (ESI): C13 NaO
2
3
)
1
H), 7.39 – 7.33 (m, 1H), 7.29 (d, J = 7.0 Hz, 1H), 7.01 (d,
J = 8.2 Hz, 1H), 4.95 (s, 2H), 4.55 (q, J = 7.1 Hz, 2H),
H
16
N
2
1
3
+
1
.50 (t, J = 7.1 Hz, 3H), 1.45 (s, 9H); C NMR (101 MHz,
CDCl ) δ 166.0, 153.7, 150.9, 131.2, 130.8, 127.8, 127.0,
24.1, 113.1, 83.1, 63.6, 44.5, 28.0 (3C), 14.2; HRMS
[M+Na] calculated: 255.1104, found: 255.1101.
3
(3nb) 3-ethoxy-6-fluoro-1-methylquinoxalin-2(1H)-one
1
1
H NMR (400 MHz, CDCl
1H), 7.22 – 7.18 (m, 1H), 7.16 – 7.11 (m, 1H), 4.55 (q, J =
7.1 Hz, 2H), 3.71 (s, 3H), 1.50 (t, J = 7.1 Hz, 3H); 13
NMR (101 MHz, CDCl ) δ 159.1 (d, J = 242.7 Hz), 154.8
3
) δ 7.33 (dd, J = 9.1, 2.8 Hz,
+
(
ESI): C16
H
20
N
2
NaO
4
[M+Na] calculated: 327.1315,
found: 327.1341.
C
3
7
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
(
s), 150.8 (s), 132.2 (d, J = 11.9 Hz), 128.2 (d, J = 2.3 Hz),
(3tb)
methyl
2-ethoxy-4-methyl-3-oxo-3,4-
1
2
14.5 (d, J = 9.2 Hz), 114.2 (d, J = 23.8 Hz), 113.4 (d, J =
3.1 Hz), 63.8 (s), 29.7 (d, J = 5.3 Hz), 14.1 (s); ATR-
dihydroquinoxaline-6-carboxylate
H NMR (400 MHz, CDCl ) δ 7.94 – 7.93 (m, 2H), 7.63 (d,
3
J = 8.7 Hz, 1H), 4.57 (q, J = 7.1 Hz, 2H), 3.97 (s, 3H),
3.76 (s, 3H), 1.51 (t, J = 7.1 Hz, 3H); C NMR (101 MHz,
CDCl ) δ 166.3, 155.2, 151.0, 134.7, 131.3, 128.1, 127.4,
3
124.9, 115.3, 64.0, 52.5, 29.7, 14.1; ATR-FTIR (cm ):
2922, 1677, 1591, 1456, 1313, 1234, 1114, 1048, 768;
1
-
1
FTIR (cm ): 2965, 1669, 1619, 1576, 1458, 1372, 1275,
119, 1078; HRMS (ESI): C11 NaO
[M+Na]+
calculated: 245.0697, found: 245.0693.
3ob) 3-ethoxy-1-methyl-6-(trifluoromethyl)quinoxalin-
(1H)-one
13
1
H
11FN
2
2
-
1
(
2
1
+
H NMR (400 MHz, CDCl
3
) δ 7.74 (d, J = 8.3 Hz, 1H),
HRMS (ESI): C13
found: 263.1026.
H
15
N
2
O
4
[M+H] calculated:263.1026,
7
1
1
1
4
.61 – 7.47 (m, 2H), 4.60 (q, J = 7.1 Hz, 2H), 3.78 (s, 3H),
1
3
.53 (t, J = 7.1 Hz, 3H); C NMR (101 MHz, CDCl
3
) δ
(3ub) 2-ethoxy-4-methyl-3-oxo-3,4-dihydroquinoxaline-
55.2, 150.9, 133.6, 131.6, , 128.7 (q, J = 33.0 Hz), 128.0,
23.9 (q, J = 273.2 Hz), 120.5 (q, J = 3.7 Hz), 111.0 (q, J =
6-carbonitrile
1
3
H NMR (400 MHz, CDCl ) δ 7.71 – 7.65 (m, 1H), 7.58 –
.1 Hz) , 64.1, 29.7, 14.1; HRMS (ESI): C12
H
12
F
3
N
2
O
2
7.51 (m, 2H), 4.58 (q, J = 7.1 Hz, 2H), 3.73 (s, 3H), 1.51 (t,
+
13
[
M+H] calculated: 273.0845, found: 273.0840.
3
J = 7.1 Hz, 3H); C NMR (101 MHz, CDCl ) δ 155.6,
(
3pb) 8-chloro-3-ethoxy-1-methylquinoxalin-2(1H)-one
150.7, 134.5, 132.0, 128.3, 127.2, 118.5, 117.7, 110.0, 64.4,
29.7, 14.1; ATR-FTIR (cm ): 2925, 2233, 1683, 1613,
1
-1
H NMR (400 MHz, CDCl
3
) δ 7.39 – 7.36 (m, 1H), 7.31 –
7
3
.27 (m, 1H), 7.21 – 7.09 (m, 1H), 4.65 – 4.59 (m, 2H),
1559, 1460, 1312, 1251, 1129, 1045; HRMS (ESI):
.72 – 3.71 (m, 3H), 1.55 – 1.51 (m, 3H); 1 C NMR (101
3
C
12
H
N
O
[M+H] calculated:230.0924, found: 230.0921.
+
12
3
2
MHz, CDCl
3
) δ 153.8, 150.8, 132.8, 132.0, 128.1, 126.7,
(5aa) 3-(Ethylthio)-1-methylquinoxalin-2(1H)-one
H NMR (400 MHz, CDCl ) δ 7.76 (dd, J = 7.9, 1.4 Hz,
3
1H), 7.50 – 7.46 (m, 1H), 7.37 – 7.35 (m, 1H), 7.33 – 7.31
-
1
1
1
2
24.7, 112.4, 64.1, 29.9, 14.0; ATR-FTIR (cm ): 2979,
357, 1663, 1605, 1466, 1370, 1275, 1134, 1014, 785;
+
HRMS (ESI): C11
found: 239.0581; HRMS (ESI): C11
calculated: 261.0401, found: 261.0405.
3qb) 8-bromo-3-ethoxy-1-methylquinoxalin-2(1H)-one
H
12ClN
2
O
2
[M+H] calculated: 239.0582,
(m, 1H), 3.71 (s, 3H), 3.19 (q, J = 7.4 Hz, 2H), 1.42 (t, J =
[M+Na]+
7.4 Hz, 3H); C NMR (101 MHz, CDCl
13
H
2
12ClN O
2
3
) δ 160.0, 153.4,
133.6, 131.4, 128.3, 128.2, 123.8, 113.8, 29.3, 24.0, 13.8;
-
1
(
ATR-FTIR (cm ): 2961, 1654, 1600, 1534, 1464. 1343,
1251, 1172, 1079, 755; HRMS (ESI): C11 NaOS
1
H NMR (400 MHz, CDCl
3
) δ 7.58 (dd, J = 7.1, 1.9 Hz,
12 2
H N
+
1
3
H), 7.25 – 7.18 (m, 2H), 4.63 (q, J = 7.1 Hz, 2H), 3.71 (s,
H), 1.53 (t, J = 7.1 Hz, 3H); C NMR (101 MHz, CDCl )
3
[M+Na] calculated: 243.0563, found: 243.0589.
1
3
(5ab) 3-(isopropylthio)-1-methylquinoxalin-2(1H)-one
1
δ 154.0, 150.9, 132.6, 129.2, 128.0, 127.2, 122.8, 113.1,
3
H NMR (600 MHz, CDCl ) δ 7.75 (d, J = 8.0 Hz, 1H),
-
1
6
1
4.3, 29.9, 14.0; ATR-FTIR (cm ): 2922, 1622, 1464,
368, 1273, 1204, 1131, 1051; HRMS (ESI):
7.48 – 7.45 (m, 1H), 7.32 (t, J = 7.6 Hz, 1H), 7.28 (d, J =
8.3 Hz, 1H), 4.00 (hept, J = 6.8 Hz, 1H), 3.70 (s, 3H), 1.46
+
13
C
11
H
12BrN
2
O
2
[M+H] calculated: 283.0077, found,
(d, J = 6.9 Hz, 6H); C NMR (151 MHz, CDCl
3
) δ 160.0,
2
(
83.0075.
3rb) 3-ethoxy-6-methoxy-1-methylquinoxalin-2(1H)-
one
3rb') 3-ethoxy-7-methoxy-1-methylquinoxalin-2(1H)-
153.3, 133.6, 131.3, 128.2, 128.1, 123.8, 113.7, 34.5, 29.3,
-
1
22.6 (2C); ATR-FTIR (cm ): 2985, 1646, 1466, 1384,
1175, 1080, 748; HRMS (ESI): C12
NaOS [M+Na]+
calculated: 257.0719, found : 257.0740.
(5ac) 3-(tert-butylthio)-1-methylquinoxalin-2(1H)-one
14 2
H N
(
one
1
1
H NMR (400 MHz, CDCl
3
) δ 7.15 (d, J = 9.1 Hz, 1H),
3
H NMR (400 MHz, CDCl ) δ 7.75 (d, J = 7.8 Hz, 1H),
7
3
.13 – 6.66 (m, 2H), 4.56 – 4.47 (m, 2H), 3.89 – 3.87 (m,
H), 3.69 – 3.67 (m, 3H), 1.52 – 1.47 (m, 3H); 13C NMR
) δ 158.7, 156.3, 154.4, 152.2, 151.4,
7.44 (t, J = 7.5 Hz, 1H), 7.32 – 7.28 (m, 1H), 7.27 – 7.25
(m, 1H), 3.68 (s, 3H), 1.68 (s, 9H); C NMR (101 MHz,
13
(
101 MHz, CDCl
3
3
CDCl ) δ 160.7, 153.4, 133.3, 131.3, 128.3, 128.2, 123.8,
-
1
1
1
1
1
50.7, 132.6, 132.1, 128.4, 125.6, 125.4, 115.2, 114.4,
10.2, 110.0, 98.7, 63.5, 63.1, 55.7, 55.7, 29.6, 29.5, 14.2,
113.8, 47.3, 29.7 (3C), 29.4; ATR-FTIR (cm ): 2954,
1655, 1530, 1466, 1364, 1166, 1077; HRMS (ESI):
-
1
13 16 2
C H N
NaOS [M+Na]+ calculated: 271.0876, found:
4.2; ATR-FTIR (cm ): 2963, 2363, 1670, 1598, 1466,
303, 1261, 1096, 1027, 802; HRMS (ESI): C12
H
15
N
2
O
3
271.0863.
+
[
(
2
M+H] calculated: 235.1077, found: 235.1077；HRMS
(5ad) 3-(cyclohexylthio)-1-methylquinoxalin-2(1H)-one
1
+
3
H NMR (400 MHz, CDCl ) δ 7.72 (d, J = 7.5 Hz, 1H),
ESI): C12
57.0884.
3sb) 3-ethoxy-6,7-difluoro-1-methylpyrazino[2,3-
15 2 3
H N O [M+Na] calculated: 257.0879, found,
7.42 (t, J = 7.3 Hz, 1H), 7.34 – 7.27 (m, 1H), 7.26 – 7.24
m, 1H), 3.91-3.85 (m, 1H), 3.67 (s, 3H), 2.13 – 2.11 (m,
H), 1.82 – 1.79 (m, 2H), 1.66 – 1.34 (m, 6H); 13C NMR
(101 MHz, CDCl ) δ 159.7, 153.3, 133.5, 131.3, 128.2,
28.0, 123.7, 113.7, 42.2, 32.5 (2C), 29.3, 26.0 (2C), 25.9;
(
2
(
b]pyrazin-2(1H)-one
1
H NMR (400 MHz, CDCl
3
) δ 7.46 – 7.41 (m, 1H), 7.09 –
3
1
7
.05 (m, 1H), 4.53 (q, J = 7.0 Hz, 2H), 3.68 (s, 3H), 1.50 (t,
1
3
-1
J = 7.1 Hz, 3H); C NMR (101 MHz, CDCl
=
3
) δ 154.1 (d, J
ATR-FTIR (cm ): 2923, 1647, 1599, 1466, 1313, 1269,
1175, 1079, 749; HRMS (ESI): C15
NaOS [M+Na]+
calculated: 297.1032, found: 297.1032.
(5ae) 3-(heptylthio)-1-methylquinoxalin-2(1H)-one
2.2 Hz), 150.7 (s), 149.2 (dd, J = 227.9, 14.0 Hz), 146.7
18 2
H N
(
(
dd, J = 224.8, 14.0 Hz), 128.2 (dd, J = 8.4, 2.2 Hz), 127.5
dd, J = 9.8, 2.9 Hz), 115.3 (dd, J = 18.7, 1.4 Hz), 102.4 (d,
-
1
1
J = 23.2 Hz), 63.8 (s), 30.0 (s), 14.1 (s); ATR-FTIR (cm ):
965, 1667, 1611, 1516, 1445, 1384, 1285, 1108, 0.38, 798;
H NMR (400 MHz, CDCl
3
) δ 7.73 (d, J = 7.6 Hz, 1H),
7
.43 (t, J = 7.3 Hz, 1H), 7.32 – 7.26 (m, 2H), 3.69 (s, 3H),
2
+
HRMS (ESI): C11
found:241.0787.
H
11
F
2
N
2
O
2
[M+H] calculated:241.0783,
3.16 (t, J = 7.0 Hz, 2H), 1.80 – 1.44 (m, 4H), 1.37 – 1.22
(m, 6H), 0.89 (t, J = 6.0 Hz,, 3H); 13C NMR (101 MHz,
3
CDCl ) δ 160.2, 153.4, 133.5, 131.4, 128.3, 128.1, 123.8,
8
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Advanced Synthesis & Catalysis
10.1002/adsc.201901008
1
13.8, 31.8, 29.7, 29.3, 29.1, 28.9, 28.6, 22.7, 14.2; ATR-
= 3.5 Hz), 113.2 (q, J = 4.1 Hz), 31.2, 21.9, 13.9; ATR-
-
1
-1
FTIR (cm ): 2920, 1644, 1600, 1467, 1346, 1173, 1079,
7
3
FTIR (cm ): 2920, 1679, 1523, 1458, 1349, 1228, 1127,
50; HRMS (ESI): C16
H
22
N
2
NaOS [M+Na]+ calculated:
1079;
HRMS
(ESI):
C
12
H
11
F
3
N
2
OS
[M+H]+
13.1345, found: 313.1336.
calculated:289.0617, found:289.0612.
(
5af) 1-methyl-3-(tetradecylthio)quinoxalin-2(1H)-one
(5ck)
2(1H)-one
3-(propylthio)-7-(trifluoromethyl)quinoxalin-
1
H NMR (400 MHz, CDCl
7
3
3
) δ 7.75 (d, J = 7.9 Hz, 1H),
.45 (t, J = 8.3 Hz, 1H), 7.34 – 7.28 (m, 2H), 3.71 (s, 3H),
.17 (t, J = 7.4 Hz, 2H), 1.75 (quint, J = 7.4 Hz, 2H), 1.48
1
6
H NMR (400 MHz, DMSO-d ) δ 12.76 (s, 1H), 7.92 (s,
1H), 7.74 – 7.72 (m, 1H), 7.44 (d, J = 8.5 Hz, 1H), 3.12 (t,
(
quint, J = 6.8 Hz, 2H), 1.36 – 1.23 (m, 20H), 0.88 (t, J =
J = 7.2 Hz, 2H), 1.76 – 1.66 (m, 2H), 1.02 (t, J = 7.3 Hz,
.8 Hz, 3H); 1 C NMR (101 MHz, CDCl
3
3H). C NMR (101 MHz, DMSO-d
13
6
1
2
2
1
3
) δ 160.2, 153.4,
6
) δ 163.2, 153.4, 133.4,
33.5, 131.4, 128.3, 128.1, 123.8, 113.7, 31.9, 29.7, 29.7,
9.7, 29.7, 29.6, 29.6, 29.5, 29.4, 29.3, 29.2, 29.1, 28.6,
132.0, 124.8 (q, J = 3.6 Hz), 124.5 (q, J = 272.7 Hz), 124.2
(q, J = 32.6 Hz), 124.2 (q, J = 3.9 Hz),117.2, 31.1, 22.0,
-
1
-1
2.7, 14.1; ATR-FTIR (cm ): 2917, 1643, 1599, 1469,
13.9; ATR-FTIR (cm ): 2921, 1684, 1624, 1459, 1326,
345, 1173, 1078, 749; HRMS (ESI): C23
H
37
N
2
OS [M+H]+
1123,
1064;
HRMS
(ESI):
12 11 3 2
C H F N OS
+
calculated: 389.2621, found: 389.2622.
[M+H] calculated: 289.0617, found:289.0621.
(
5ag) 1-methyl-3-(phenethylthio)quinoxalin-2(1H)-one
(5dc) 3-(tert-butylthio)-6,7-dichloroquinoxalin-2(1H)-
1
H NMR (400 MHz, CDCl
.43 (t, J = 7.7 Hz, 1H), 7.35 – 7.32 (m, 5H), 7.28 – 7.22
m, 2H), 3.67 (s, 3H), 3.40 (t, J = 8.0 Hz, 2H), 3.05 (t, J =
3
) δ 7.76 (d, J = 7.9 Hz, 1H),
one
1
7
(
6
H NMR (400 MHz, DMSO-d ) δ 12.55 (s, 1H), 7.91 (s,
1H), 7.40 (s, 1H), 1.61 (s, 9H); 13C NMR (101 MHz,
DMSO-d ) δ 163.6, 152.8, 131.8, 130.3, 130.1, 128.1,
125.6, 117.0, 47.5, 29.7(3C); ATR-FTIR (cm ): 2957,
.6 Hz, 2H); 1 C NMR (101 MHz, CDCl
3
7
1
1
2
3
) δ 159.7, 153.4,
6
-
1
40.6, 133.5, 131.4, 128.7 (2C), 128.6 (2C), 128.3 (2C),
-
1
26.5, 123.9, 113.8, 35.2, 31.1, 29.3; ATR-FTIR (cm ):
1667, 1541, 1457, 1165, 1067; HRMS (ESI):
+
925, 1644, 1580, 1460, 1346, 1279, 1174, 1077, 754;
C
12
H
2
12Cl N
2
NaOS [M+Na] calculated: 324.9940, found:
+
HRMS (ESI):
19.0876. found: 319.0882.
5ah) ethyl 2-((4-methyl-3-oxo-3,4-dihydroquinoxalin-2-
17
C H
16
N
2
NaOS [M+Na] calculated:
324.9944.
(5ek) 2-oxo-3-(propylthio)-1,2-dihydroquinoxaline-6-
3
(
carbonitrile
1
yl)thio)acetate
6
H NMR (400 MHz, DMSO-d ) δ 12.71 (s, 1H), 7.78 (d, J
1
H NMR (400 MHz, CDCl
3
) δ 7.69 (d, J = 7.8 Hz, 1H),
= 8.3 Hz, 1H), 7.66 – 7.64 (m, 1H), 7.60 (d, J = 1.7 Hz,
1H), 3.13 (t, J = 7.2 Hz, 2H), 1.76 – 1.67 (m, 2H), 1.02 (t,
7
7
3
1
1
1
[
(
2
.46 (t, J = 7.8 Hz, 1H), 7.33 – 7.27 (m, 2H), 4.23 (q, J =
.1 Hz, 2H), 3.94 (s, 2H), 3.68 (s, 3H), 1.30 (t, J = 7.1 Hz,
H); 13C NMR (101 MHz, CDCl
) δ 169.0, 158.4, 153.1,
33.2, 131.6, 128.7, 128.3, 124.0, 113.9, 61.7, 32.5, 29.3,
J = 7.4 Hz, 3H); 13C NMR (101 MHz, DMSO-d
) δ 165.2,
153.1, 134.9, 130.9, 128.3, 126.9, 120.1, 118.9, 110.0, 31.2,
6
3
-
1
21.9, 13.9; ATR-FTIR (cm ): 2958, 2226, 1673, 1525,
-
1
4.3; ATR-FTIR (cm ): 2972, 1644, 1598, 1463, 1383,
306, 1159, 1095, 755; HRMS (ESI): C13 NaO
1455, 1383, 1234, 1136, 1077; HRMS (ESI): C12
[M+H] calculated: 246.0696, found:246.0699.
H
11
N
3
OS
+
H
14
N
2
3
S
+
M+Na] calculated: 301.0617, found: 301.0620.
5ai) 3-((3-mercaptopropyl)thio)-1-methylquinoxalin-
(1H)-one
(5fc) 3-(tert-butylthio)-6,7-dimethylquinoxalin-2(1H)-
one
1
6
H NMR (400 MHz, DMSO-d ) δ 12.28 (s, 1H), 7.45 (s,
1
13
H NMR (400 MHz, CDCl
3
) δ 7.77 (dd, J = 7.9, 1.3 Hz,
1H), 7.02 (s, 1H), 2.28 (s, 6H), 1.61 (s, 9H); C NMR (101
) δ 159.9, 153.3, 138.0, 132.4, 130.9,
1
3
(
(
H), 7.50 – 7.45 (m, 1H), 7.37 – 7.28 (m, 2H), 3.72 (s, 3H), MHz, DMSO-d
6
.31 (t, J = 7.0 Hz, 2H), 2.71 (q, J = 7.1 Hz, 2H), 2.08
128.0, 127.3, 116.0, 46.7, 29.8(3C), 20.1, 19.3; ATR-FTIR
quint, J = 7.0 Hz, 2H), 1.48 (t, J = 8.0 Hz, 1H); 13C NMR
101 MHz, CDCl ) δ 159.6, 153.4, 133.4, 131.4, 128.4,
28.3, 123.9, 113.8, 32.8, 29.3, 27.8, 23.7; ATR-FTIR (cm-
(cm ): 2920, 1651, 1526, 1450, 1361, 1164, 1073; HRMS
-1
3
(ESI):
found:263.1204.
(5gc) 3-(tert-butylthio)-8-chloroquinoxalin-2(1H)-one
14 19 2
C H N
OS [M+H]+ calculated: 263.1213,
1
1
)
: 2923, 1640, 1598, 1463, 1315, 1173, 1079, 753; HRMS
+
1
(
ESI): C12
found: 289.0454.
5aj) 3-(allylthio)-1-methylquinoxalin-2(1H)-one
H
14
N
2
NaOS
2
[M+Na] calculated: 289.0440,
H NMR (400 MHz, DMSO-d
6
) δ 12.00 (s, 1H), 7.62 (d, J
= 7.7 Hz, 1H), 7.53 (d, J = 7.8 Hz, 1H), 7.31 – 7.24 (m,
13
(
1H), 1.61 (s, 9H). C NMR (101 MHz, DMSO-d
6
) δ 162.8,
1
H NMR (400 MHz, CDCl
H), 7.49 – 7.45 (m, 1H), 7.36 – 7.29 (m, 2H), 6.05 – 5.94
m, 1H), 5.41 – 5.15 (m, 2H), 3.85 (d, J = 6.9 Hz, 2H),
3
) δ 7.79 (dd, J = 7.9, 1.3 Hz,
153.6, 133.4, 128.7, 127.5, 126.4, 124.2, 119.0, 47.2,
-
1
1
(
29.7(3C); ATR-FTIR (cm ): 2961, 1662, 1527, 1458,
1384, 1065, 940, 724; HRMS (ESI): C12 NaOS
H13ClN
2
.72 (s, 3H); 1 C NMR (101 MHz, CDCl
3
) δ 159.3, 153.3,
[M+Na] calculated: 291.0329, found: 291.0322.
+
3
1
2
1
[
(
3
33.4, 133.0, 131.5, 128.4 (2C), 123.9, 118.2, 113.8, 32.5,
(5hc) 3-(tert-butylthio)-6,7-difluoroquinoxalin-2(1H)-
-
1
9.3; ATR-FTIR (cm ): 2921, 1638, 1600, 1535, 1464,
344, 1173, 1079, 969, 754; HRMS (ESI): C12 NaOS
one
1
H
12
N
2
6
H NMR (400 MHz, DMSO-d ) δ 12.49 (s, 1H), 7.72 –
+
M+Na] calculated: 255.0563, found: 255.0565.
5bk) 3-(propylthio)-6-(trifluoromethyl)quinoxalin-
(1H)-one
7.68 (dd, J = 11.1, 8.2 Hz, 1H), 7.18– 7.13 (m , 1H), 1.59
(s, 9H); 13C NMR (101 MHz, DMSO-d
) δ 162.3 (d, J =
6
2
2.6 Hz), 152.8 (s), 149.4 (dd, J = 247.7, 14.6 Hz), 146.2
(dd, J = 242.2, 14.2 Hz), 128.7 (dd, J = 10.0, 2.4 Hz),
1
6
H NMR (400 MHz, DMSO-d ) δ 12.71 (s, 1H), 7.86 (d, J
=
1
8.9 Hz, 1H), 7.59 – 7.58 (m, 2H), 3.16 (t, J = 7.2 Hz, 2H), 127.3 (d, J =9.1，1.0 Hz), 115.0 (d, J = 18.5 Hz), 103.8 (d,
.79 – 1.70(m, 2H), 1.06 (t, J = 7.4 Hz, 3H); 13C NMR
-1
J = 21.9 Hz), 47.2 (s), 29.7 (3C); ATR-FTIR (cm ): 2921,
1670, 1510, 1470, 1386, 1292, 1166, 1070, 756; HRMS
(
101 MHz, DMSO-d
6
) δ 164.5, 153.2, 134.5, 130.7, 128.3,
1
28.0 (q, J = 32.1 Hz), 124.3 (q, J = 272.2 Hz), 120.1 (q, J
9
This article is protected by copyright. All rights reserved.

Advanced Synthesis & Catalysis
10.1002/adsc.201901008
+
(
2
ESI): C12
71.0710.
5ic) 3-(tert-butylthio)-7-fluoroquinoxalin-2(1H)-one
H
13
F
2
N
2
OS [M+H] calculated: 271.0711, found:
G. G. Pawar, S. V. Kumar, Y. Jiang, D. Ma, Angew.
Chem. Int. Ed. 2017, 56, 16136–16179.
(
[2] a) J. F. Hartwig, Angew. Chem. Int. Ed. 1998, 37,
2046–2067; b) J. F. Hartwig, Nature 2008, 455,
314–322; c) T. Hu, T. Schulz, C. Torborg, X. Chen,
J. Wang, M. Beller, J. Huang, Chem. Commun. 2009
7330–7332; d) A. Aranyos, D. W. Old, A.
Kiyomori, J. P. Wolfe, J. P. Sadighi, S. L.
1
H NMR (400 MHz, DMSO-d
.46 (m, 1H), 7.37 – 7.23 (m, 2H), 1.61 (s, 9H); 13C NMR
101 MHz, DMSO-d ) δ 163.2 (s), 158.5 (d, J = 239.5 Hz),
52.9 (s), 132.6 (d, J = 11.8 Hz), 126.9 (d, J = 1.6 Hz),
17.3 (d, J = 9.4 Hz), 116.4 (d, J = 24.3 Hz), 112.5 (d, J =
6
) δ 12.46 (s, 1H), 7.49 –
7
(
1
1
2
1
6
,
-
1
2.8 Hz), 47.2 (s), 29.7(3C); ATR-FTIR (cm ): 2922,
662, 1558, 1496, 1261, 1117, 1069; HRMS (ESI):
Buchwald, J. Am. Chem. Soc. 1999, 121, 4369–4378;
e) K. E. Torraca, X. Huang, C. A. Parrish, S. L.
Buchwald, J. Am. Chem. Soc. 2001, 123, 10770–
10771; f) C. H. Burgoes, T. E. Barder, X. Huang, S.
L. Buchwald, Angew. Chem. Int. Ed. 2006, 45,
4321–4326; g) T. Itoh, T. Mase, Org. Lett. 2004, 6,
4587–4590.
+
C
2
12
H
13FN
2
NaOS [M+Na] calculated: 275.0625, found,
75.0617.
(
5jc) 3-(tert-butylthio)-7-chloroquinoxalin-2(1H)-one
1
H NMR (400 MHz, DMSO-d
8.3 Hz, 1H), 7.30 – 7.22 (m, 2H), 1.60 (s, 9H); 13C NMR
101 MHz, DMSO-d ) δ 162.0, 153.0, 132.5, 131.2, 131.1,
28.8, 123.9, 115.2, 47.1, 29.7(3C); ATR-FTIR (cm ):
961, 1663, 1526, 1383, 1067, 934; HRMS (ESI):
6
) δ 12.47 (s, 1H), 7.64 (d, J
=
(
1
2
C
6
[3] a) O. Bistri, A. Correa, C. Bolm, Angew. Chem. Int.
Ed. 2008, 47, 586–588; b) A. Correa, M. Carril, C.
Bolm, Angew. Chem. Int. Ed. 2008, 47, 2880–2883;
c) Y.-Y. Lin, Y.-J. Wang, C.-H. Lin, J.-H. Cheng,
C.-F. Lee, J. Org. Chem. 2012, 77, 6100–6106; d)
W.-Y. Wu, J.-C. Wang, F.-Y. Tsai, Green Chem.
2009, 11, 326–329.
[4] a) J. A. Terrett, J. D. Cuthbertson, V. W. Shurtleff,
D. W. C. MacMillan, Nature 2015, 524, 330–334; b)
S. Jammi, P. Barua, L. Rout, P. Saha, T.
Punniyamurthy, Tetrahedron Lett. 2008, 49, 1484–
1487; c) C. Cavedon, A. Madani, P. H. Seeberger, B.
Pieber, Org. Lett. 2019, 21, 5331–5334.
[5] a) L. Niu, J. Liu, X.-A. Liang, S. Wang, A. Lei, Nat.
Commun. 2019, 10, 467; b) A. Lipp, G. Lahm, T.
Opatz, J. Org. Chem. 2016, 81, 4890–4897; c) C. A.
Huff, R. D. Cohen, K. D. Dykstra, E. Strechfuss, D.
A. Dirocco, S. W. Krska, J. Org. Chem. 2016, 81,
6980–6987; d) C. A. Correia, L. Yang, C.-J. Li, Org.
Lett. 2011, 13, 4581–4583; e) T. He, L. Yu, L.
Zhang, L. Wang, M. Wang, Org. Lett. 2011, 13,
5016–5019.
-
1
+
12
H
13ClN
2
NaOS [M+Na] calculated: 291.0329, found:
2
(
91.0322.
5kc)
dihydroquinoxaline-6-carboxylate
methyl
3-(tert-butylthio)-2-oxo-1,2-
1
H NMR (400 MHz, DMSO-d
1.5 Hz, 1H), 7.81 – 7.79 (m, 1H), 7.75 – 7.73 (m, 1H),
.89 (s, 3H), 1.63 (s, 9H); C NMR (101 MHz, DMSO-d
δ 165.9, 164.6, 153.1, 134.9, 130.0, 128.9, 127.5, 124.2,
17.3, 52.9, 47.4, 29.6(3C); ATR-FTIR (cm ): 2923, 2359,
725, 1661, 1531, 1454, 1384, 1220, 1130, 1064, 760;
6
) δ 12.57 (s, 1H), 7.87 (d, J
=
3
1
3
6
)
-
1
1
1
+
HRMS (ESI): C14
found: 293.0951.
H
17
N
2
O
3
S [M+H] calculated: 293.0954,
(
6fb) 2-(3-ethoxy-2-oxoquinoxalin-1(2H)-yl)acetic acid
H NMR (400 MHz, DMSO-d
.46 – 7.40 (m, 2H), 7.37 – 7.28 (m, 1H), 5.01 (s, 2H),
.45 (q, J = 7.0 Hz, 2H), 1.40 (t, J = 7.0 Hz, 3H); C NMR
) δ 169.2, 153.8, 150.5, 131.4, 130.8,
27.6, 127.4, 124.3, 114.9, 63.4, 44.3, 14.5; HRMS (ESI):
1
6
) δ 7.60 (d, J = 7.8 Hz, 1H),
7
4
(
1
C
13
101 MHz, DMSO-d
6
+
12
H
12
N
2
NaO
4
[M+Na] calculated: 271.0689, found:
2
71.0685.
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We are grateful to the Natural Science Foundation of China
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1
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FULL PAPER
(
Thio)etherification of Quinoxalinones under
Visible-Light Photoredox Catalysis
Adv. Synth. Catal. Year, Volume, Page – Page
a
b
b
Jiadi Zhou, Peng Zhou, Tingting Zhao, Quanlei
b
a,b*
Ren, and Jianjun Li
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