H-phosphonate-mediated amination of quinoline N-oxides with tertiary amines: A mild and metal-free synthesis of 2-dialkylaminoquinolines

Article abstract of DOI:10.1002/adsc.201301065

A synthetic strategy has been developed for the synthesis of 2-dialkylaminoquinolines from easily available quinoline N-oxides, tertiary amines, diisopropyl H-phosphonate and carbon tetrachloride (CCl₄) in one pot under metal-free conditions at room temperature.

Full text of DOI:10.1002/adsc.201301065

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DOI: 10.1002/adsc.201301065
H-Phosphonate-Mediated Amination of Quinoline N-Oxides
with Tertiary Amines: A Mild and Metal-Free Synthesis of
2-Dialkylaminoquinolines
Xiaolan Chen,a,* Xu Li,a Zhibo Qu,a Diandian Ke,a Lingbo Qu,b Likun Duan,a
Wenpeng Mai,b Jinwei Yuan,b Jianyu Chen,a and Yufen Zhaoa,c,*
a
College of Chemistry and Molecular Engineering, Zhengzhou University, Key Laboratory of Organic Chemistry and
Chemical Biology, Henan Province, Zhengzhou 450052, Peopleꢀs Republic of China
Fax : (+86)-371-6776-7051; phone: (+86)-371-6776-7051; e-mail: chenxl@zzu.edu.cn
Chemistry and Chemical Engineering School, Henan University of Technology, Henan Province, Zhengzhou 450001,
b
Peopleꢀs Republic of China
Department of Chemistry, Xiamen University, Xiamen 361005, Peopleꢀs Republic of China
c
E-mail: yfzhao@xmu.edu.cn
Received: November 27, 2013; Revised: March 3, 2014; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201301065.
Abstract: A synthetic strategy has been developed
for the synthesis of 2-dialkylaminoquinolines from
easily available quinoline N-oxides, tertiary amines,
diisopropyl H-phosphonate and carbon tetrachlor-
ide (CCl4) in one pot under metal-free conditions at
room temperature.
be obtained by any variant of the Chichibabin reac-
tion. This means that we have not been able as yet to
accomplish the direct introduction of dialkylamino
groups into the quinoline nucleus using alkali dialkyl-
AHCTUNGTRENNUNG
amides.[9] A survey of the literature shows that deriva-
tization of a 2-unsubstituted quinoline moiety in
a complex molecule to the corresponding 2-dialkyl-
ACHTUNGTRENaNGNU minoquinoline is under most circumstances achieved
via indirect synthetic methods. The most traditional
approach is amination of 2-haloquinolines and ana-
logues with dialkylamines. However, to use this ap-
proach, a halogen atom must be installed at the 2-po-
sition first, and this is usually done by chlorination of
quinoline N-oxides with poor 2,4-regioselectivity or
À
À
Keywords: C H activation; C N coupling; 2-di-
alkylaminoquinolines; H-phosphonates; quinoline
N-oxides
A
2-Aminoquinoline and related natural/unnatural con- low yields (Scheme 1b).[10] Londregan et al. have de-
geners are pharmaceutically important alkaloids.[1] veloped a facile amination procedure for the synthesis
They exhibit a wide range of pharmaceutical activities of 2-aminopyridines, however, when the method was
including antimalarial,[2] anti-HIV,[3] anti-Alzheimer employed to synthesize 2-cyclohexylaminoquinoline,
disease,[4] anthelmintic,[5] antidepressant,[6] and antihy- a 2-alkylaminoquinoline, the yield was relatively low,
pertensive[7] activities etc. They are attractive study and meanwhile the phosphonium salt PyBroP used as
targets and are anticipated as potent leads in the me- the substrate activator in this reaction, is relatively ex-
dicinal chemistry community. There are several meth- pensive.[11] Pedersen et al. have demonstrated the syn-
ods available in the literature for the synthesis of 2- thesis of 2-(dialkylamino)quinolines, by treating acet-
aminoquinoline derivatives. The first approach is the
ACHTUNGTRENaNGNU nilides and N,N-dialkylformamides with a mixture of
Chichibabin reaction, through which amino or alkyl- phosphorus pentoxide and a dialkyamine at 2508C.[12a]
amino groups can be introduced directly into the But this method usually suffers from obvious limita-
quinoline nucleus by the reaction of quinoline with tions which include high temperature, long reaction
alkali amide or alkali alkylamide. However, the Chi- time, especially low yield (Scheme 1c). Liꢀs group
chibabin reaction generally suffers from several draw- very recently developed the synthesis of 2-aminoqui-
backs, such as unsatisfactory yields, poor functional noline N-oxides (Scheme 1d) starting from lactams or
tolerance and poor regioselectivity due to the strongly cycloamines and quinoline N-oxides, but metal salts
basic conditions, high temperatures and prolonged re- such as Ag2CO3 and Cu
(OAc)2 were needed to acti-
action times (Scheme 1a).[8] It is especially worth vate the C-2 H bond at a high temperature, and be-
mentioning that 2-(dialkylamino)quinolines can never sides, PCl3, a harsh phosphorus reagent, was required
À
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Xiaolan Chen et al.
Scheme 1. Comparison of previous works with this work
in the following step for the transformation of 2-ami- to “flexibility”, makes the cheap and easily prepared
À
noquinoline N-oxides to the corresponding final 2- dialkyl H-phosphates unexpectedly efficient C-2 H
aminoquinolines.[12b] Over the past decades, the devel- activators of the quinoline moiety in amination pro-
opment of simple and convenient approaches leading cesses.
directly to 2-(dialkylamino)quinolines from easily
available starting materials without metals still re- for the optimized conditions using the model reaction
mains a challenge. of quinoline N-oxide (1a) with triethylamine (2a) in
We initiated this unprecedented study by screening
Herein, we disclose an unprecedented synthetic the presence of dialkyl H-phosphonates and CCl4. In
method by which a series of 2-(dialkylamino)quino- the one-pot amination process, triethylamine (2a) was
lines are readily prepared by direct reaction of quino- transferred to an N,N-diethylamino group at the 2 po-
line N-oxides with trialkylamines at room tempera- sition of a quinoline ring by way of the loss of one of
ture in the presence of diisopropyl H-phosphonate the N-ethyl groups. The screening results are summar-
and CCl4 (Scheme 1e). It is well known that dialkyl ized in Table 1. The influence of a variety of dialkyl
H-phosphonates occupy a major position in organo- H-phosphonates on the model reaction was first in-
phosphorus chemistry since they are frequently inter- vestigated (Table 1, entries 1–5). A high yield of 3a
mediates in the synthesis of a variety of bioactive was obtained when diisopropyl H-phosphonate
products including aminophosphosphonates, amino- (DIPPH) was employed (83%) (Table 1, entry 5). The
À
phosphonic acids, P C phosphonates, hydroxyalkyl investigation on the influence of solvents indicates
phosphonates, amidophosphates, nucleoside H-phos- that THF was the most effective solvent among those
phonates, poly(alkylene H-phosphonate)s and poly(al- tested (Table 1, entries 5–10). The subsequent investi-
kylene phosphate)s, phosphorus-containing polyesters, gation on the influence of temperature (Table 1, en-
etc.[13] Here, we would like to disclose a newly discov- tries 5 and 11–16) reveals that the amination reaction
ered aspect of H-phosphonate chemistry, which, due worked best at a temperature of 208C (entry 5). It
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H-Phosphonate-Mediated Amination of Quinoline N-Oxides
Table 1. Optimization of the amination conditions.[a]
Entry H-Phosphonate
Solvent Temperature
Et3N
(mmol)
H-Phosphonate
(mmol)
CCl4
(mL)
Isolated Yield
[%][b]
(HPO(OR)2, R=)
[8C]
1
2
3
4
5
6
7
8
CH3
CH2CH3
Ph
THF
THF
THF
THF
THF
CH3CN r.t.
toluene r.t.
dioxane r.t.
DMSO r.t.
ethanol r.t.
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
THF
r.t.
r.t.
r.t.
r.t.
r.t.
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
1
2
4
3
3
3
3
3
3
3
3
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
0
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.3
0.4
0.6
80
74
35
52
83
37
trace
78
26
trace
33
42
66
74
71
65
7
42
81
nr
13
50
67
80
47
72
81
CH2Ph
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
CH
ACHTUNGTRENNUNG
A
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
T
U
G
N
R
N
G
A
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
G
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
G
A
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
À10
0
10
30
40
60
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
0.5
1.0
1.5
2.5
rt
rt
rt
[a]
Optimal conditions: 1a (1.0 mmol), 2a (1–4 mmol), DIPPH (0–2.5 mmol), CCl4 (0–0.6 mL), solvent (15 mL) at room tem-
perature for 8 h.
Isolated yields.
[b]
can be seen that the yield increased over the tempera-
ACHTUNGTRENaNGNU mine. Reactions of quinoline N-oxide with dietha-
ture range of 10 to 208C, from 33% to 83%, and then nolamine and diethylamine produced the correspond-
gradually decreased to 65% after 608C was reached. ing 2-di(2-hydroxyethyl)aminoquinoline (3d) and 2-di-
The ideal amounts of reactants that were needed to ethylaminoquinoline (3a), respectively, indicating that
form the product, including Et3N (Table 1, entries 5, besides trialkylamines, dialkylamines are potentially
and 17–19), DIPPH (Table 1, entries 5, and 20–24), suitable for the reaction. Regrettably, pyridine N-
and CCl4 (Table 1, entries 5, and 25–27), were also ex- oxide could not work well when reacted with triethyl-
plored. The result indicates that the amount of reac- amine under the optimized reaction conditions (3y).
tants employed in entry 5 still brought about the most It is worth reminding that the amination method
satisfying yield.
cannot be applied to primary amines. When propan-
ACHTUNGTRENaNGNU mine was employed to react with quinoline N-oxide,
With the promising results obtained from the
model reaction, we then examined the substrate scope the reaction could not render the corresponding prod-
of quinolines and tertiary amines. As shown in uct (3z). To our delight, the amination method can be
Table 2, all the representative tertiary amines reacted fully applied to isoquinoline N-oxide. Reactions of
well with quinoline N-oxide itself, giving the resulting isoquinoline N-oxide with tertiary amines regioselec-
2-dialkylaminoquinolines in moderate to good yields tively produced the three corresponding 1-dialkylami-
(3a–c). The amination method can also be applied to noisoquinolines (3e–g). Furthermore, quinoline N-
two secondary amines, diethanolamine and diethyl- oxides bearing electron-donating and electron-with-
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Table 2. Scope of the amination of quinolines with tertiary amines.[a,b]
[a]
Reaction conditions: 1 (1.0 mmol), 2 (3.0 mmol), DIPPH (2.0 mmol), CCl4 (0.5 mL), in THF (15 mL), at room
temperature for 8 h.
Isolated yields.
Detected by TLC
[b]
[c]
drawing substituents (CH3, Br, OCH3 and NO2) were amines as in the cases of 3a–c, 3e–g, 3h–j, 3k–m, 3n–
also employed to react with all the tertiary amines, p, 3q–s, and 3t–v. It is worth noticing that unsymmet-
furnishing the corresponding products (3h–v) in mod- rical tertiary amines also reacted with quinoline N-
erate to good yields, respectively. It can be seen that oxide, over a selective loss of one of the three N-at-
the yields always slightly decreased with increasing tached alkyl groups, forming the corresponding 2-di-
carbon chain length of the corresponding tertiary
ACHTUNGTRENaNUGN lkylaminoquinolines (3w–x). For example, ethyldiiso-
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H-Phosphonate-Mediated Amination of Quinoline N-Oxides
Scheme 2. Proposed mechanism of the H-phosphonate mediated amination reaction
propylamine reacted with quinoline N-oxide, over ammonium cations. When N,N-dimethylcyclohex-
a selective loss of an N-attached propyl group, form-
ACHTUNGTRENUNaNG mine 7 was employed, ammonium cation 8 was
ing the corresponding 2-(N-ethyl-N-isopropylamino)- formed. It is likely that an SN2 reaction, in this case,
quinoline (3w); N,N-dimethylcyclohexylamine reacted took place in the following step, because ammonium
with quinoline N-oxide, over a selective loss of an N- cation 8 offered less sterically hindered sites. A chlo-
methyl group, forming 2-(N-methyl-N-cyclohexylami- ride anion, acting as nucleophile, attacked the least
no)quinoline 3x.
hindered methyl group carbon, and the leaving group,
A plausible mechanism for the amination reaction in this case, the final product 2-(N-cyclohexyl-N-
is proposed (Scheme 2). Diisopropyl phosphite 1, at methylamino)quinoline 3x, immediately began to
its starting stage, was converted into reactive dialkyl depart. Finally methyl chloride and 3x were generat-
chlorophosphate 2 in the presence of carbon tetra- ed. When N,N-diisopropylethylamine 9 was employed
chloride and triethylamine, as in the Atherton–Todd as nucleophile, ammonium cation 10 was formed.
reaction.[13] Subsequently, the oxygen atom of quino- Then an energetically favorable E2 elimination reac-
line N-oxide (3) acting as a nucleophile started to tion was followed because of the relatively high steric
attack the phosphorus atom of 2 and triggers an addi- hindrance of 10. Amine 9 acting as a base (B:) started
tion–elimination process. A chloride anion was ex- to remove one of the hydrogens from the b-carbon of
pelled as a leaving group and quinolinium cation 4 the N-isopropyl group, and the leaving group, in this
was formed. Meanwhile an energetically favorable case, the final product 2-(N-ethyl-N-isopropylamino)-
six-membered ring was generated inside 4 due to the quinoline (3w), began to depart, forming a transition
À
formation of an intramolecular hydrogen bond (C-2
state with an alkene-like structure. The proton was re-
À
H···O=P), by which the covalent C-2 H of intermedi- moved from a b-carbon of the N-attached propyl
ate 4 was effectively activated and an energetically fa- group rather than from the N-attached ethyl group in
vorable elimination of diisopropyl phosphate 5 was order to achieve the most stable alkene-like transition
followed along with the formation of quinolinium state. Finally, a propene molecule was eliminated
cation 6. By the way, the newly formed 5 reacted with from 10 and the final product 3w was formed.
dialkyl chlorophosphate 2, forming tetraisopropyl py- 31P NMR spectroscopy was used to trace the related
rophosphate 11. A wide range of tertiary amines can progress of the reactions. The reaction was carried
act as nucleophiles and attack the positively charged out using quinoline N-oxide, triethylamine, DIPPH,
carbon of 6, forming the corresponding quaternary CCl4 as reactants. The whole process was monitored
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Figure 1. 31P NMR stacks diagram of the reaction process.
by 31P NMR every 20 min. The related phosphorus-
containing compounds, 1, 2 and 11,[14] were all well
tracked in the proper sequence as shown in Figure 1.
This 31P NMR stacks diagram strongly backed the
proposed mechanism.
In conclusion, we have developed a straightforward
methodology by which a wide variety of 2-(dialkyl-
ACHTUNGTRENNUNGamino)quinolines can be prepared in a one-pot reac-
stirred at room temperature for 8 h. The solvent was evapo-
rated under vacuum, and the residue was quenched with
water (5 mL), extracted with ethyl acetate (3ꢂ5 mL). The
combined organic layers were washed with brine (15 mL)
and dried over anhydrous Na2SO4. After filtration, the sol-
vent was evaporated under vacuum. The crude product was
purified by silica gel chromatography (petroleum ether:
ethyl acetate=10:1) to give the desired product.
tion of quinoline N-oxides with trialkylamines at
room temperature in the presence of diisopropyl H-
phosphonate and CCl4. We have disclosed a new
Supporting Information
Experimental procedures, compound characterizations, and
1
the copies of H NMR, 13C NMR and HR-mass spectra are
aspect of H-phosphonate chemistry through the first
available in the Supporting Information.
2
À
H-phosphonate involved in an sp C N coupling reac-
tion. The six-membered ring formed by intramolecu-
lar hydrogen bonding inside intermediate
4
(Scheme 2) played an important role in terms of acti-
vating the C-2 H covalent bond of quinoline N-oxide.
Compared with literature methods for indirect
Acknowledgements
À
Financial support from the National Natural Science Founda-
tion of China (No. 21072178), Innovation Specialist Projects
of Henan Province (No. 114200510023), Technology and Sci-
ence talent Cultivation Project in Zhengzhou City (No.
112PLJRC359), The Special Fund for the Doctoral Program
of Higher Education (No. 20124101110003), and the Founda-
tional and Frontier Technology Research Foundation of
Henan Province (No. 132300410027) is gratefully acknowl-
edged.
dialkylACHTUNGTRENNUNGamination of quinoline, great advantages of
this strategy include high efficiency, readily available
starting materials and reagents, a metal-free one-pot
procedure, and extremely mild reaction conditions.
The method will undoubtedly be a far superior alter-
native for the synthesis of a variety of therapeutically
significant 2-dialkylaminoquinoline derivatives. Fur-
ther studies on the applications of this strategy will be
reported in due course.
References
[1] T. Takashi, T. Yusuke, M. Toshihide, Org. Biomol.
Chem. 2012, 10, 5113–5118.
Experimental Section
[2] a) K. J. Raynes, P. A. Stocks, P. M. OꢀNeill, B. K. Park,
S. A. Ward, J. Med. Chem. 1999, 42, 2447–2451;
b) A. K. Suleiman, A. Ahmad, D. El-Eisawi, A. Al-
Shibib, J. Nat. Prod. 1998, 61, 262.
Typical Procedure
Quinoline N-oxide (1.0 mmol), tertiary amine (3.0 mmol),
DIPPH (2.0 mmol), CCl4 (0.5 mL) in THF (15 mL) were
6
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ÝÝ
These are not the final page numbers!

COMMUNICATIONS
H-Phosphonate-Mediated Amination of Quinoline N-Oxides
[3] a) W. D. Wilson, M. Zhao, S. E. Patterson, R. L. Wydra,
L. Janda, L. Strekowski, Med. Chem. Res. 1992, 2, 102–
110; b) L. Strekowski, J. L. Mokrosz, V. A. Honkan, A.
Czarny, M. T. Cegla, R. L. Wydra, S. E. Patterson, R. F.
Schinazi, J. Med. Chem. 1991, 34, 1739–1746.
[4] a) G. R. Proctor, A. L. Harvey, Curr. Med. Chem. 2000,
7, 295–302; b) Y. Cheng, T. C. Judd, M. D. Bartberger,
J. Brown, K. Chen, R. T. Fremeau, S. A. Hitchcock,
S. W. Louie, T. S. Powers, E. A. Sickmier, P. H. Wen, S.
Wood, J. Med. Chem. 2011, 54, 5836–5857.
A. Lafuente, Tetrahedron 2005, 61, 9042–9051; c) D.
Cuperly, P. Gros, Y. Fort, J. Org. Chem. 2002, 67, 238–
241; d) J. Mathieu, P. Gros, Y. Fort, Chem. Commun.
2000, 951–952; e) T. Imahori, M. Uchiyama, Y. Kondo,
Chem. Commun. 2001, 2450–2452.
[11] a) A. T. Londregan, S. Jennings, L. Q. Wei, Org. Lett.
2010, 12, 5254–5257; b) A. T. Londregan, S. Jennings,
L. Q. Wei, Org. Lett. 2011, 13, 1840–1843.
[12] a) B. W. Hansen, E. B. Pedersen, Liebigs Ann. Chem.
1981, 8, 1485–1491; b) G. Li, C. Q. Jia, K. Sun, Org.
Lett. 2013, 15, 5198–5201.
[5] J. R. Pfister, J. Nat. Prod. 1988, 51, 969–970.
[6] A. A. Alhaider, M. A. Abdelkader, E. J. Lien, J. Med.
Chem. 1985, 28, 1394–1398.
[13] a) J. Stawinski, A. Kraszewski, Acc. Chem. Res. 2002,
35, 952–960; b) J. Stawinski, in: Handbook of Organo-
phosphorus Chemistry, (Ed.: R. Engel), Marcel
Dekker, New York. 1992, pp 377–434; c) Y. X. Gao, G.
Wang, L. Chen, P. Xu, Y. F. Zhao, Z. B. Zhou, L.-B.
Han, J. Am. Chem. Soc. 2009, 131, 7956–7957; d) K. D.
Troev, Chemistry and application of H-phosphonates,
Elsevier Science 2006, Vol. 84, pp 438–442.
[14] a) Y. B. Zhou, S. F. Yin, Y. X. Gao, Y. F. Zhao, L. B.
Han, Angew. Chem. 2010, 122, 7004–7007; Angew.
Chem. Int. Ed. 2010, 49, 6852–6855; b) G. M. Kosolap-
off, R. M. Watson, J. Am. Chem. Soc. 1951, 73, 4101–
4102; c) G. M. Steinberg, J. Org. Chem. 1949, 14, 637–
647; d) P. J. Garegg, J. Stawinski, R. Stromberg, J. Org.
Chem. 1987, 52, 284–287; e) J. Acharya, A. K. Gupta,
M. P. Kaushik, Tetrahedron Lett. 2005, 46, 5293–5295;
f) H. K. Gupta, P. Garg, D. K. Dubey, Tetrahedron Lett.
2008, 49, 6704–6706.
[7] S. F. Campbell, J. D. Hardstone, M. J. Palmer, J. Med.
Chem. 1988, 31, 1031–1035.
[8] a) G. Nydia, F. W. Luthy, H. S. M. Bergstrom, J. Am.
Chem. Soc. 1949, 71, 1109–1110; b) J. Gurnos, The
Chemistry of Heterocyclic Compounds, Quinolines, Vol.
I, John Wiley & Sons, Inc., New York, 1977; c) J. Yin,
B. Xiang M. Huffman, C. E. Raab, I. W. Davies, J. Org.
Chem. 2007, 72, 4554–4557; d) A. E. Chichibabin, O. A.
Zeide, J. Russ. Phys. Chem. Soc. 1914, 46, 1212; e) F. P.
Alexander, A. M. Simonov, V. N. Doron’kin, Russ.
Chem. Rev. 1978, 47, 1042.
[9] Z. R. Wang, Comprehensive Organic Name Reactions
and Reagents, John Wiley & Sons, Inc., Hoboken, N.J.,
2009.
[10] a) C. K. McGill, A. Rappa, Adv. Heterocycl. Chem.
1988, 44, 1–79; b) J. G. Rodrꢃguez, D. L. R. Cristobal,
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8 H-Phosphonate-Mediated Amination of Quinoline N-
Oxides with Tertiary Amines: A Mild and Metal-Free
Synthesis of 2-Dialkylaminoquinolines
Adv. Synth. Catal. 2014, 356, 1 – 8
Xiaolan Chen,* Xu Li, Zhibo Qu, Diandian Ke, Lingbo Qu,
Likun Duan, Wenpeng Mai, Jinwei Yuan, Jianyu Chen,
Yufen Zhao*
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