Divergent Synthesis of Functionalized Quinolines from Aniline and Two Distinct Amino Acids

Article abstract of DOI:10.1021/acs.joc.7b01501

A practicable quinoline synthesis from aniline and two amino acids was developed for generating a wide range of quinolines with high efficiency and diversity. Thus, it facilitated the creations of pharmaceutical derivatives, photochemical active compounds, and challenging scaffolds. The concept of using two amino acids as heterocyclic precursors has been raised for the first time. Mechanistic studies revealed that I₂ enabled decarboxylation, oxidative deamination, and selective reconstruction of new C-N and C-C bonds processes.

Full text of DOI:10.1021/acs.joc.7b01501

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Note
Divergent Synthesis of Functionalized Quinolines
from Aniline and Two Distinct Amino Acids
Jia-Chen Xiang, Zi-Xuan Wang, Yan Cheng, Shi-Qing Xia,
Miao Wang, Bo-Cheng Tang, Yan-Dong Wu, and An-Xin Wu
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.7b01501 • Publication Date (Web): 28 Jul 2017
Downloaded from http://pubs.acs.org on July 28, 2017
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Divergent Synthesis of Functionalized Quinolines
from Aniline and Two Distinct Amino Acids
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JiaꢀChen Xiang,a ZiꢀXuan Wang,a Yan Cheng,a ShiꢀQing Xia,a Miao Wang,a
BoꢀCheng Tang,a YanꢀDong Wua and AnꢀXin Wu*ab
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a Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, College of Chemistry,
Central China Normal University, Hubei, Wuhan 430079, P. R. China
b State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu, Lanzhou 730000,
P. R. China
Supporting Information Placeholder
TOC Graphic:
ABSTRACT: A practicable quinoline synthesis from aniline and two amino acids was developed for
generating a wide range of quinolines with high efficiency and diversity. Thus it facilitated the creations of
pharmaceutical derivatives, photochemical active compounds and challenging scaffolds. The concept of
using two amino acids as heterocyclic precursors has been raised for the first time. Mechanistic studies
revealed that I2 enabled decarboxylation, oxidative deamination and selective reconstruction of new CꢀN and
CꢀC bonds processes.
Amino acid, which industrially produced from fermentation process, is a versatile motif utilized in
biochemistry,1 pharmaceutical chemistry2 and total synthesis.3 In Nature, amino acids are prebiotic material
in the biosynthesis of heterocyclic alkaloids.4 If being used to prepared vital heterocycles biomimetically,
these environmentally benign, nonꢀfossil carbon and biomass feedstock are promising candidates for
replacing fossil carbon sources such as crude oil, the reserve of which are dwindling.5 However, synthetic
methodologies for directly converting amino acids into heterocycles are rare.6 More importantly, using two
(or multi) amino acids together as heterocyclic precursors to improve the synthetic diversity,7 potꢀeconomy8
and chemical ideality9 is fascinating and still need to be explored.10 We attempted to use two distinct amino
acids simultaneously to prepare value added heterocycles.
As one of the most common heterocyclic molecule,11 functionalized quinolines are present in many
pharmacologically and biologically active chemicals,11b therefore methods for their synthesis are widely
researched.12ꢀ14 However, existing methods are unable or tedious to prepare pharmaceutical and
photochemically active quinoline compounds such as directly modified drug derivatives and conjugated
fused rings due to the limilation of substrates scope or selectivity. A unified approcach for functionalized
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quinolines starts from commercially available and userꢀfriendly materials is still desirable. Especially, a
method that enables direct assembly of bioactive quinoline compounds from biomass amino acids in a
metalꢀfree condition could profoundly affect pharmaceutical manufacture.11b Herein, we detailed an protocol
for unified quinoline synthesis using aniline and two distinct amino acids: one with only an αꢀH atom and
the other with two βꢀH atoms.
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The initial investigation focused on the model reaction of phenylalanine (1a),
2ꢀaminoꢀ2ꢀ(2ꢀchlorophenyl)acetic acid (2j), and pꢀtoluidine (3a) in DMSO. Based on the reaction conditions
in our previous studies, 1.0 equiv of I2 was used as an additive (Table1, entry 1).10 Trifluoroacetic acid (50
mol%) was added to promote oxidative deamination of the amino acids. The desired 2,3ꢀdisubstituted
o
quinoline 4j was obtained in 58% yield as the major product at 100 C. Several Brønsted acids were
investigated to increase the yield (entries 2–5). A higher yield, i.e., 81%, was achieved with the assistance of
50 mol% HI (entry 2). Next, we investigated the effect of I2 loading (entries 6–10). No reaction occurred in
the absence of I2. However, more than 1.0 equiv of I2 reduced the yield (entries 9 and 10). Some other
highꢀboilingꢀpoint solvents were also surveyed (entries 11–14). The yields obtained by using the polar
solvents DMF, DMA, and NMP were lower than those achieved with DMSO. Sulfolane resulted in only a
moderate yield. The ratios of three reactants were also carefully screened and the optimum ratios were 1:1:1
(Table 1).
Table 1. Reaction Optimization.a
entry
I2 (equiv)
solvent
acid
yield (%)b
1
2
1.0
1.0
1.0
1.0
1.0
0
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMF
TFA
58
81
HI
3
sulfanilic acid
29
4
TfOH
PTA[c]
HI
40
5
trace
trace
trace
74
6
7
0.2
0.5
1.5
2.0
1.0
1.0
1.0
1.0
HI
8
HI
9
HI
60
10
11
12
13
14
HI
trace
35
HI
DMA
HI
34
NMP
HI
75
sulfolane
HI
56
a1a (1.0 mmol), 2j (1.0 mmol), 3a (1.0 mmol), acid (0.5 mmol), I2 and solvent (3.0
mL) were added in a pressure vessel, then stirred at 100 oC for 10 h. b Isolated yields.
cPTA = pꢀphthalic acid.
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After establishing the optimum conditions, we investigated the amino acid scope (Scheme 1).
Phenylalanine derivatives with various groups on the phenyl ring were first examined. Compound 4a was
obtained in 77% yield under the standard conditions. 2ꢀAminoꢀ3ꢀ(naphthalenꢀ2ꢀyl)propanoic acid, in which
the electronꢀwithdrawing naphthalene ring also causes steric hindrance, gave a good result (4b, 81%). The
reaction of 4ꢀnitroꢀsubstituted phenylalanine gave the desired product (4c, 80%). Slightly lower yields were
achieved using phenylalanine analogs with electronꢀdonating substituents on the aromatic ring (4d, 72%; 4e,
70%). The sensitive substrate tyrosine generated the corresponding quinoline in reasonable yield (4f, 75%).
Amino acids with halogen substituents aromatic rings gave desired products smoothly (4g, 80%; 4h, 83%; 4i,
85%), which enabled further coupling derivatization. Various phenylglycine derivatives with halogen
substituents were tolerated and furnished the desired products (4j, 81%; 4k, 76%). When a substrate bearing
a hydroxyl group was used, the yield declined to a moderate level (4l, 44%). Notably, 3ꢀarylquinolines were
obtained using glycine as substrate 2 (4m, 72%; 4n, 45%). When aspartic acid was used as 1,
2ꢀphenylquinoline and its derivatives were formed through spontaneous decarboxylation in the presence of I2.
Aspartic acid acts as a twoꢀcarbon unit to participate in the transformation, which provides a delightful
improvement in reaction scopes (4o, 70%; 4p, 37%). Based on these results, aspartic acid derivatives
bearing different functional groups, e.g., asparaginate and methyl ester, were examined to give medium
yields (4q–4s, 42ꢀ74%). 3ꢀ(4ꢀHydroxyphenyl)quinoline derivatives (4t, 69%), which have attracted attention
because of their biological activities11c, were also obtained using our method. This reaction system was also
compatible with aliphatic amino acids with two βꢀH atoms. For example, a combination of norleucine and
phenylglycine gave the desired product 4u in 50% yield. Amino acid bearing a sensitive cyclopropane could
also afford the desired product 4v in 65% yield without ring opening. Furthermore, methionine could
transform into the target molecular with a sulfur methyl side chain (4w, 48%).
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Scheme 1. Scope of Amino Acids.
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aReaction conditions: 1 (1.0 mmol), 2 (1.0 mmol), 3 (1.0 mmol), HI (0.5 mmol, 57 wt% solution in H2O), I2 (1.0 mmol), and
DMSO (3.0 mL) were added to a pressure vessel. The mixture was stirred at 100 °C for 10 h. Isolated yield.
To further judge the practicability of our method, we investigated aniline substrates 3 with different
aromatic and heterocyclic rings (Scheme 2). A series of 4ꢀsubstituted anilines containing electronꢀdonating
and withdrawing groups were tested. There was no obvious substituent effect and the corresponding
products were efficiently constructed (5a–5d, 68ꢀ77%). Fusedꢀring quinolines derived from 1ꢀnaphthylamine
and 2ꢀnaphthylamine were tolerated in the reaction (5e, 61%; 5f, 66%). Conjugated aromatic substituents
pyrene substrate gave 5g in 31% yield. Fluorenes with an aromatic amine were used to afford quinoline
derivatives with four consecutive fused rings (5h–5k, 44ꢀ74%). The framework of 5j which containing a
highly planar structure and four free rotation benzene rings increased the possibility of this kind of material
to express AIE effect.15 In addition, the heterocyclic substrate 5ꢀmethylꢀ1Hꢀpyrazolꢀ3ꢀamine provided the
desired product 5k in 70% yield. Moreover, Using bisꢀamines, this transformation could provide a smooth
way
to
afford
functionalized
biquinolines.
pꢀphenylenediamine,
biphenyldiamine
and
4,4'ꢀmethylenedianiline were extensively investigated and compounds 5l, 5m and 5n were synthesized for
the first time. Notably, 5l is an analogue of nꢀtype organic semiconductor16a which literaturely needs five
linear steps synthesis including a Friedlander quinoline synthesis from commercial available materials.16b
Biquinolines 5m and 5n with carbon linkages are reported exhibiting potential antimalarial activities.11 It is
attractive for the incorporation of pyridine rings into natural products and drug candidates containing an
aniline backbone. The lateꢀstage modification was conducted using naturally occurring coumarin 120. Two
compounds 5o and 5p were obtained in 74% overall yield with a regioselective ratio of 1:1.4. The
commercial available antiꢀsteroid drug aminoglutethimide was converted to the corresponding quinoline
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derivative in 67% yield (5q). Derivatives of the chiral lactone drug (1S)ꢀ(−)ꢀcamphanic acid chloride
participated in this reaction to generate the desired quinoline 5r (53%).
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Scheme 2. Scope of Aniline Substrates.
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aReaction conditions: 1a (1.0 mmol), 2a (1.0 mmol), 3 (1.0 mmol), HI (0.5 mmol, 57 wt% solution in H2O), I2 (1.0 mmol), and
DMSO (3.0 mL) were added to a pressure vessel. The mixture was stirred at 100 °C for 10 h. †These types of functionalized
quinoline were synthesized for the first time. ‡0.5 equiv (0.5 mmol) of 3 was used.
Scheme 3. Control Experiments.
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Control experiments were performed to clarify the mechanism (Scheme 3). Compounds 1a and 2a were
stirred under the standard conditions without addition of 3a. The α,βꢀunsaturated aldehyde M1 was formed
(Scheme 3, entry 1). Treatment of 1a under the same conditions gave a 3,5ꢀdisubstituted pyridine 9, which
was derived from the phenylacetaldehyde intermediate M2 in our previous work10 (Scheme 3, entry 2). The
benzaldehyde derivative M3 was isolated when 2a alone was subjected to these conditions (Scheme 3, entry
3). These results indicate that both amino acids were transformed into the corresponding aldehydes. The
userꢀunfriendly materials phenylacetaldehyde and benzaldehyde together with pꢀtoluidine (1:1:1) as the
starting material gave 4a in 57% yield with other inevitable byproducts (Scheme 3, entry 4).18 Compared to
the result in standard conditions (Scheme 1, 77%), this result suggested that the amino groups of amino acid,
aniline and the ammonia which generated in situ from oxidative cleavage promote the transformation
through endogenous imine activation process. To prove this point, exogenous amino compounds such as
ammonium hydroxide (1.0 equiv) and excessive pꢀtoluidine (0.5 equiv) were added respectively as parallel
experiments (Scheme 3, entry 3). The yields of 4a were slightly improved in both cases as expected (61%
and 69%). However, we consider the direct use of aldehydes to be toxic to both human and the environment.
Moreover, 4j could not be obtained when M1 was reacted with 3a, which suggested that M1 might not be
the key intermediate (Scheme 3, entry 5). The use of phenethylamine and benzylamine instead of amino
acids as starting materials did not give 4j (Scheme 3, entry 6). This suggested that decarboxylative oxidation
is essential in the transformation.19
On the basis of the results described and previous studies,20, 21 we have proposed a preliminary mechanistic
insight (Scheme 4). The transformation is triggered by I2ꢀenabled decarboxylative oxidation reactions of
amino acids to afford imine intermediates (i). The imines then undergo rapid hydrolysis in an acidic medium
to generate the corresponding aldehyde (iii) and ammonia. This cascade reaction is catabolism processes to
activate the amino acids in situ. Phenylalanine and phenylglycine afford phenylacetaldehyde (iii-1) and
benzaldehyde (iii-2), respectively. Condensation of iii-1 with endogenous amino species (amino acids or
ammonia or aniline) leads the formation of imine M4.21 Through tautomerism, enamine intermediate M5 can
be generated reversibly. Parallelly, benzaldehyde iii-2 undergoes condensation with aniline to give imine M6.
Then M6 is captured by M5 to generate intermediate M7. Under the assistance of imine activation process,
Friedel–Crafts reaction provides tetrahydroquinoline M8. Regeneration of the oxidant iodine by the
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interaction of HI and DMSO20 leads to further oxidative aromatization of M8 to give the final quinoline
4
5
products via amine elimination.
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Scheme 4. Possible Reaction Mechanism.
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In summary, we have developed a novel method for 2,3ꢀdisubstituted, 2ꢀsubstituted and 3ꢀsubstituted
quinoline syntheses from one aniline and two distinct amino acids. Functionalized quinolines with various
substituent patterns including challenging fused rings and biquinolines which have never been prepared
before can be readily reached. The use of renewable resources amino acids and metalꢀfree conditions makes
this reaction a userꢀfriendly process, which will be useful in pharmaceutical discovery, photochemical
application and industrial production. Mechanistically, an I2ꢀenabled decarboxylation and deamination
process activates two distinct amino acids in situ, and then I2 further promotes new CꢀN and CꢀC bonds
formation as a terminal oxidant. The development of using two (or multi) amino acids as heterocyclic
precursors to prepare value added targets is currently underway in our laboratory.
Experimental Section
General
All substrates and reagents were commercially available and used without further purification. TLC analysis
was performed using preꢀcoated glass plates. Column chromatography was performed using alkaline
aluminum oxide (200–300 mesh). IR spectra were recorded on a PerkinꢀElmer PEꢀ983 infrared spectrometer
as KBr pellets with absorption in cm–1.1H spectra were recorded in CDCl3 or DMSOꢀd6 on 600 MHz NMR
spectrometers and resonances (δ) are given in parts per million relative to tetramethylsilane. Data are
reported as follows: chemical shift, multiplicity (s = singlet, d = doublet, t = triplet, m = multiplet q =
quadruple), coupling constants (Hz) and integration. 13C spectra were recorded in CDCl3 or DMSOꢀd6 on 150
MHz. NMR spectrometers and resonances (δ) are given in ppm. HRMS were obtained on a Bruker 7ꢀtesla
FTꢀICR MS equipped with an electrospray source. The Xꢀray crystal structure determinations were obtained
on a Bruker SMART APEX CCD system. Melting points were determined using XTꢀ4 apparatus.
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General procedure for the synthesis
For 4 and 5 (4a as an example)
A mixture of phenylalanine 1a (1.0 mmol), phenylglycine 2a (1.0 mmol), aniline 3a (1.0 mmol), HI (50
mmol%), I2 (1.0 mmol) and DMSO (3.0 mL) were added in a pressure vessel, then stirred at 100 oC for 10 h.
Then added 50 mL water and 30 mL saturated brine solution to the mixture and extracted with EtOAc 3
times (3 × 50 mL). The extract was washed with 10% Na2S2O3 solution, dried over anhydrous Na2SO4 and
concentrated under reduced pressure. The crude product was purified by column chromatography (eluent:
petroleum ether /EtOAc=10/1) to afford the product 4a as yellow oil in 77% (226 mg).
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Analytical Data for Compounds 4 and 5
6-Methyl-2,3-diphenylquinoline (4a):
1
77% yield (226 mg); Yellow oil; IR νmax: 1632, 1495, 1053, 1027, 1006, 824, 762, 701, 625, 572 cm−1; H
NMR (DMSOꢀd6) δ 8.21 (s, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.75 (s, 1H), 7.59 (d, J = 8.4 Hz, 1H), 7.36 (d, J =
7.2 Hz, 2H), 7.27 (m, 6H), 7.22 (d, J = 6.0 Hz, 2H), 2.49 (s, 3H). 13C NMR (DMSOꢀd6) δ 156.6, 145.3,
140.2, 139.7, 136.9, 136.3, 133.8, 132.1, 129.8, 129.5, 128.5, 128.2, 127.8, 127.7, 127.2, 126.8, 126.5, 21.2.
HRMS (ESI): m/z [M+H]+ calcd for C22H18N : 296.1434.; found: 296.1448
6-Methyl-3-(naphthalen-2-yl)-2-phenylquinoline (4b):
81% yield (278 mg); Yellow crystalline; mp = 107ꢀ109 ℃; IR νmax: 1623, 1595, 1487, 1261, 1027, 913, 819,
746, 718, 695, 574, 477 cm−1; 1H NMR (CDCl3) δ 8.12 (s, 1H), 8.11 (s, 1H), 7.83 (s, 1H), 7.77 (t, J = 7.8 Hz,
2H), 7.61 (d, J = 8.4 Hz, 1H), 7.57 (s, 1H), 7.54 (d, J = 8.4 Hz, 1H), 7.45 (m, 4H), 7.20 (m, 3H), 7.15 (d, J =
8.4 Hz, 1H), 2.52 (s, 3H). 13C NMR (CDCl3) δ 157.3, 145.9, 140.3, 137.7, 137.3, 136.5, 134.2, 133.3, 132.1,
131.9, 129.9, 129.0, 128.2, 127.9, 127.6, 127.3, 127.2, 126.9, 126.1, 126.0, 21.6. HRMS (ESI): m/z [M+H]+
calcd for C26H20N : 346.1590; found: 346.1597.
6-Methyl-3-(4-nitrophenyl)-2-phenylquinoline (4c):
80% yield (273 mg); Yellow crystalline; mp = 172ꢀ174 ℃; IR νmax: 1595, 1514, 1493, 1344, 1272, 933, 845,
839, 766, 750, 721, 702, 579 cm−1; 1H NMR (CDCl3) δ 8.13 (d, J = 8.4 Hz, 2H), 8.10 (s, 2H), 7.65 (s, 1H),
7.61 (d, J = 8.4 Hz, 1H), 7.39 (m, 4H), 7.30 (m, 3H), 2.57 (s, 3H). 13C NMR (CDCl3) δ 156.7, 147.0, 146.7,
146.2, 139.6, 137.2, 132.8, 132.1, 130.5, 129.9, 129.1, 128.3, 128.2, 126.8, 126.3, 123.4, 21.7. HRMS (ESI):
m/z [M+H]+ calcd for C22H17N2O2 : 341.1285; found: 341.1287
3-(4-methoxyphenyl)-6-methyl-2-phenylquinoline (4d):
72% yield (235 mg); Brown oil; IR νmax: 1631, 1610, 1512, 1259, 1178, 1024, 832, 796, 696, 581 cm−1; 1H
NMR (DMSOꢀd6) δ 8.23 (s, 1H), 7.96 (d, J = 7.8 Hz, 1H), 7.79 (s, 1H), 7.61 (d, J = 8.4 Hz, 1H), 7.37 (s, 2H),
7.31 (s, 3H), 7.16 (d, J = 6.6 Hz, 2H), 6.88 (d, J = 6.6 Hz, 2H), 3.75 (s, 3H), 2.52 (s, 3H). 13C NMR
(DMSOꢀd6) δ 158.5, 156.8, 145.1, 140.5, 136.7, 136.4, 133.6, 132.0, 130.8, 129.8, 128.5, 127.9, 127.8, 127.0,
126.5, 113.8, 55.1, 21.3. HRMS (ESI): m/z [M+H]+ calcd for C23H20NO : 326.1539.; found: 326.1547
3-(4-(benzyloxy)phenyl)-6-methyl-2-phenylquinoline (4e):
70% yield (280 mg); Brown oil; IR νmax: 1608, 1510, 1488, 1452, 1368, 1284, 1240, 1176, 1023, 831, 760,
735, 719, 697, 581 cm−1; 1H NMR (CDCl3) δ 8.08 (d, J = 8.4 Hz, 1H), 8.01 (s, 1H), 7.57 (s, 1H), 7.53 (d, J =
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8.4 Hz, 1H), 7.48 – 7.39 (m, 5H), 7.37 (t, J = 7.2 Hz, 3H), 7.32 (d, J = 7.2 Hz, 2H), 7.13 (d, J = 7.8 Hz, 2H),
6.88 (d, J = 8.4 Hz, 2H), 5.02 (s, 2H), 2.53 (s, 3H). 13C NMR (CDCl3) δ 157.9, 157.5, 145.6, 140.6, 136.7,
136.5, 133.9, 132.6, 131.7, 130.8, 129.9, 128.9, 128.5, 128.0, 127.9, 127.7, 127.5, 127.3, 126.1, 114.5, 69.9,
21.6. HRMS (ESI): m/z [M+H]+ calcd for C29H24NO : 402.1852; found: 402.1860.
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75% yield (234 mg); Yellow crystalline; mp = 74ꢀ76 ℃; IR νmax: 1632, 1591, 1269, 1234, 1050, 1026, 1004,
817, 763, 697 cm−1; 1H NMR (DMSOꢀd6) δ 9.54 (s, 1H), 8.18 (s, 1H), 7.93 (d, J = 7.8 Hz, 1H), 7.76 (s, 1H),
7.58 (d, J = 7.8 Hz, 1H), 7.37 (s, 2H), 7.29 (s, 3H), 7.02 (d, J = 7.2 Hz, 2H), 6.70 (d, J = 7.2 Hz, 2H). 13C
NMR (DMSOꢀd6) δ 156.8, 156.7, 145.0, 140.6, 136.4, 136.3, 134.0, 131.8, 130.7, 130.1, 129.8, 128.4, 127.8,
127.7, 127.0, 126.4, 115.2, 21.3. HRMS (ESI): m/z [M+H]+ calcd for C22H17NO : 312.1383; found:
312.1389.
3-(4-chlorophenyl)-6-methyl-2-phenylquinoline (4g):
80% yield (265 mg); Yellow crystalline; mp = 155ꢀ157 ℃; IR νmax: 1640, 1487, 1189, 1088, 1026, 833, 697,
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531 cm−1; H NMR (DMSOꢀd6) δ 8.28 (s, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.80 (s, 1H), 7.64 (d, J = 8.4 Hz,
1H), 7.37 (m, 4H), 7.32 (s, 3H), 7.25 (m, 2H), 2.52 (s, 3H). 13C NMR (DMSOꢀd6) δ 156.5, 145.4, 140.0,
138.6, 137.1, 136.6, 132.7, 132.4, 132.2, 131.4, 129.8, 128.5, 128.4, 128.0, 127.9, 126.8, 126.6, 21.3. HRMS
(ESI): m/z [M+H]+ calcd for C22H17ClN : 330.1044; found: 330.1047.
3-(4-fluorophenyl)-6-methyl-2-phenylquinoline (4h):
83% yield (259 mg); Yellow crystalline; mp = 79ꢀ82 ℃; IR νmax: 1629, 1601, 1508, 1367, 1217, 1156, 836,
698, 579, 524 cm−1; 1H NMR (DMSOꢀd6) δ 8.27 (s, 1H), 7.97 (d, J = 7.2 Hz, 1H), 7.79 (s, 1H), 7.63 (d, J =
7.8 Hz, 1H), 7.35 (s, 2H), 7.30 (s, 3H), 7.27 (s, 2H), 7.16 (s, 2H), 2.52 (s, 3H). 13C NMR (DMSOꢀd6) δ 162.3,
160.7, 156.6, 145.3, 140.1, 137.0, 136.5, 136.1, 132.9, 132.2, 131.6, 131.6, 129.8, 128.5, 127.9, 127.8, 126.8,
126.5, 115.3, 115.1, 21.3. HRMS (ESI): m/z [M+H]+ calcd for C22H17FN : 314.1340; found: 314.1350.
3-(3,4-dichlorophenyl)-6-methyl-2-phenylquinoline (4i):
85% yield (307 mg); Yellow crystalline; mp = 133ꢀ135 ℃; IR νmax: 1487, 1361, 1027, 922, 825, 793, 709,
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609 cm−1; H NMR (DMSOꢀd6) δ 8.34 (s, 1H), 7.98 (d, J = 8.4 Hz, 1H), 7.80 (s, 1H), 7.65 (d, J = 8.4 Hz,
1H), 7.58 – 7.51 (m, 2H), 7.36 (m, 5H), 7.13 (d, J = 7.8 Hz, 1H), 2.53 (s, 3H). 13C NMR (DMSOꢀd6) δ 156.3,
145.5, 140.4, 139.8, 137.3, 136.7, 132.6, 131.4, 131.0, 130.3, 130.1, 130.0, 129.8, 128.5, 128.2, 128.0, 126.7,
126.6, 21.3. HRMS (ESI): m/z [M+H]+ calcd for C22H16Cl2N : 364.0654; found: 364.0663.
2-(2-chlorophenyl)-6-methyl-3-phenylquinoline (4j):
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81% yield (266 mg); Black oil; IR νmax: 1623, 1497, 1448, 1346, 1029, 905, 826, 762, 696, 666 cm−1; H
NMR (CDCl3) δ 8.09 (m, 2H), 7.64 (s, 1H), 7.57 (d, J = 8.4 Hz, 1H), 7.41 – 7.38 (m, 1H), 7.28 – 7.19 (m,
8H), 2.56 (s, 3H). 13C NMR (CDCl3) δ 156.0, 145.4, 139.8, 139.0, 137.0, 136.1, 135.3, 132.9, 132.0, 131.4,
129.4, 129.4, 129.2, 129.0, 127.8, 127.6, 127.1, 126.5, 126.3, 21.6. HRMS (ESI): m/z [M+H]+ calcd for
C22H17ClN : 330.1044; found: 330.1040.
2-(4-fluorophenyl)-6-methyl-3-phenylquinoline (4k):
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76% yield (237 mg); Yellow oil; IR νmax: 1601, 1486, 1221, 1015, 844, 824, 798, 700, 571 cm−1; H NMR
(DMSOꢀd6) δ 8.28 (s, 1H), 7.98 (d, J = 8.4 Hz, 1H), 7.82 (s, 1H), 7.64 (d, J = 8.4 Hz, 1H), 7.39 (m, 2H),
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7.37 – 7.31 (m, 3H), 7.26 (d, J = 6.6 Hz, 2H), 7.12 (t, J = 8.4 Hz, 2H), 2.53 (s, 3H). 13C NMR (DMSOꢀd6) δ
162.7, 161.0, 155.6, 145.2, 139.6, 137.1, 136.7, 136.5, 133.8, 132.3, 132.0, 129.6, 128.4, 127.4, 126.9, 126.5,
114.8, 114.6, 21.3. HRMS (ESI): m/z [M+H]+ calcd for C22H17FN : 314.1340; found: 314.1343.
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44% yield (137 mg); Brown crystalline; mp = 206ꢀ209 ℃; IR νmax: 1603, 1493, 1447, 1348, 1281, 1169,
1024, 906, 826, 762, 696, 516 cm−1; 1H NMR (DMSOꢀd6) δ 9.16 (s, 1H), 8.51 (s, 1H), 7.95 (d, J = 7.8 Hz,
1H), 7.85 (s, 2H), 7.79 (s, 1H), 7.60 (d, J = 7.8 Hz, 1H), 7.55 (s, 2H), 7.45 (s, 1H), 2.51 (s, 3H). 13C NMR
(DMSOꢀd6) δ 148.6, 145.5, 137.2, 136.5, 132.9, 132.2, 131.8, 129.3, 128.5, 128.2, 127.7, 127.2, 127.1, 21.2.
HRMS (ESI): m/z [M+H]+ calcd for C22H18NO : 312.1383; found: 312.1389.
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6-Methyl-3-phenylquinoline (4m):
72% yield (158 mg); Yellow crystalline; mp = 47ꢀ50 ℃; IR νmax: 1726, 1632, 1496, 1455, 1188, 1131, 823,
760, 690 cm−1; 1H NMR (DMSOꢀd6) δ 9.16 (s, 1H), 8.51 (s, 1H), 7.94 (d, J = 8.4 Hz, 1H), 7.86 (m, 2H), 7.79
(s, 1H), 7.60 (d, J = 7.8 Hz, 1H), 7.54 (s, 2H), 7.45 (s, 1H), 2.50 (s, 3H). 13C NMR (DMSOꢀd6) δ 148.6,
145.5, 137.2, 136.5, 132.8, 132.2, 131.8, 129.3, 128.5, 128.2, 127.7, 127.2, 127.1, 21.2. HRMS (ESI): m/z
[M+H]+ calcd for C16H14N : 220.1121; found: 220.1125.
3-Phenylquinoline (4n):
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45% yield (92 mg); Yellow oil; IR νmax: 1641, 1492, 1186, 1125, 1025, 902, 786, 762, 696 cm−1; H NMR
(DMSOꢀd6) δ 9.26 (s, 1H), 8.66 (s, 1H), 8.07 (s, 2H), 7.90 (d, J = 7.2 Hz, 2H), 7.78 (t, J = 7.2 Hz, 1H), 7.65
(t, J = 7.2 Hz, 1H), 7.56 (m, 2H), 7.47 (t, J = 7.2 Hz, 1H). 13C NMR (DMSOꢀd6) δ 149.5, 146.8, 137.1, 132.9,
129.6, 129.3, 128.7, 128.5, 128.3, 127.7, 127.2, 127.1, 124.9. HRMS (ESI): m/z [M+H]+ calcd for C15H12N :
206.0964; found: 206.0967.
6-Methyl-2-phenylquinoline (4o):
70% yield (152 mg); Yellow crystalline; mp = 54ꢀ56 ℃; IR νmax: 1724, 1612, 1490, 1463, 1447, 1283, 832,
755, 693, 564 cm−1; 1H NMR (DMSOꢀd6) δ 8.33 (d, J = 8.4 Hz, 1H), 8.26 (d, J = 6.0 Hz, 2H), 8.09 (d, J =
8.4 Hz, 1H), 7.98 (d, J = 8.4 Hz, 1H), 7.74 (s, 1H), 7.61 (d, J = 8.4 Hz, 1H), 7.55 (t, J = 6.6 Hz, 2H), 7.52 –
7.46 (m, 1H). 13C NMR (DMSOꢀd6) δ 155.2, 146.2, 139.4, 138.7, 136.5, 136.0, 132.1, 129.4, 128.9, 128.8,
127.1, 127.0, 126.5, 118.7, 21.2. HRMS (ESI): m/z [M+H]+ calcd for C16H14N : 220.1121; found: 220.1142.
2-Phenylquinoline (4p)：
37% yield (76 mg); White crystalline; mp = 60ꢀ63 ℃; IR νmax: 1726, 1615, 1489, 1281, 829, 771, 691, 675
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cm−1; H NMR (DMSOꢀd6) δ 8.45 (d, J = 8.4 Hz, 1H), 8.28 (d, J = 6.0 Hz, 2H), 8.15 (d, J = 8.4 Hz, 1H),
8.08 (d, J = 7.8 Hz, 1H), 8.00 (d, J = 7.8 Hz, 1H), 7.78 (t, J = 6.6 Hz, 1H), 7.63 – 7.58 (m, 1H), 7.55 (d, J =
6.0 Hz, 2H), 7.51 (d, J = 6.6 Hz, 1H). 13C NMR (150 MHz, DMSOꢀd6) 13C NMR (DMSOꢀd6) δ 156.1, 147.6,
138.7, 137.3, 130.0, 129.7, 129.1, 128.9, 127.9, 127.3, 127.0, 126.5, 118.8. HRMS (ESI): m/z [M+H]+ calcd
for C15H12N : 206.0964; found: 206.0969.
6-Methyl-2-phenylquinoline-3-carboxamide (4q)：
53% yield (139 mg); White crystalline; mp = 119ꢀ121 ℃; IR νmax: 1669, 1626, 1381, 1340, 923, 824, 714,
698 cm−1; 1H NMR (DMSOꢀd6) δ 8.35 (s, 1H), 8.11 (s, 1H), 7.97 (d, J = 7.8 Hz, 1H), 7.83 (s, 1H), 7.79 (d, J
= 6.6 Hz, 2H), 7.66 (d, J = 7.8 Hz, 2H), 7.47 (d, J = 6.6 Hz, 3H), 2.51 (s, 3H). 13C NMR (DMSOꢀd6) δ 170.4,
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154.9, 145.7, 140.0, 136.7, 135.0, 132.9, 131.1, 128.7, 128.6, 128.1, 126.7, 125.8, 21.3. HRMS (ESI): m/z
[M+H]+ calcd for C17H15N2O : 263.1179; found: 263.1183.
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74% yield (204 mg); Yellow crystalline; mp = 69ꢀ72 ℃; IR νmax: 1729, 1552, 1434, 1291, 1254, 1095, 1006,
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820, 712 cm−1; H NMR (DMSOꢀd6) δ 8.69 (s, 1H), 7.97 (d, J = 8.4 Hz, 1H), 7.87 (s, 1H), 7.70 (d, J = 8.4
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Hz, 1H), 7.58 (d, J = 6.0 Hz, 2H), 7.47 (d, J = 7.2 Hz, 3H), 3.70 (s, 3H). 13C NMR (DMSOꢀd6) δ 168.0,
155.8, 146.3, 140.0, 138.2, 137.2, 134.2, 128.5, 128.2, 128.2, 127.2, 125.4, 124.9, 52.5, 21.2. HRMS (ESI):
m/z [M+H]+ calcd for C18H16NO2 : 278.1176; found: 278.1176.
Methyl 6-methylquinoline-3-carboxylate (4s)：
42% yield (85 mg); White crystalline; mp = 119ꢀ121℃; IR νmax: 1714, 1442, 1341, 1282, 1248, 1233, 1102,
825, 763 cm−1; 1H NMR (DMSOꢀd6) δ 9.23 (s, 1H), 8.88 (s, 1H), 7.99 (d, J = 8.4 Hz, 1H), 7.94 (s, 1H), 7.76
(d, J = 8.4 Hz, 1H), 3.94 (s, 3H), 2.52 (s, 3H). 13C NMR (DMSOꢀd6) δ 165.4, 148.5, 147.9, 137.8, 137.4,
134.5, 128.6, 128.2, 126.5, 122.6, 52.5, 21.1. HRMS (ESI): m/z [M+H]+ calcd for C12H12NO2: 202.0868;
found: 202.0863.
4-(6-methylquinolin-3-yl)phenol (4t)：
69% yield (163 mg); Yellow crystalline; mp = 242ꢀ245 ℃; IR νmax: 1628, 1606, 1516, 1500, 1269, 1241,
838, 817, 527 cm−1; 1H NMR (DMSOꢀd6) δ 9.76 (s, 1H), 9.11 (s, 1H), 8.39 (s, 1H), 7.91 (d, J = 8.4 Hz, 1H),
7.75 (s, 1H), 7.69 (d, J = 8.4 Hz, 2H), 7.55 (d, J = 8.4 Hz, 1H), 6.93 (d, J = 8.4 Hz, 2H), 2.50 (s, 3H). 13C
NMR (DMSOꢀd6) δ 157.8, 148.5, 145.0, 136.3, 132.9, 131.2, 130.7, 128.4, 127.9, 127.8, 126.8, 116.1, 21.2.
HRMS (ESI): m/z [M+H]+ calcd for C16H14NO : 236.1070; found: 236.1073.
6-Methyl-2-phenyl-3-propylquinoline (4u)：
50% yield (130 mg); Yellow oil; IR νmax: 3056, 2959, 2929, 2869, 1597, 1488, 1443, 1378, 1266, 1013, 826,
762, 700, 575 cm−1; 1H NMR (DMSOꢀd6) δ 8.09 (s, 1H), 7.86 (d, J = 8.4 Hz, 1H), 7.67 (s, 1H), 7.51 (d, J =
7.2 Hz, 3H), 7.49 – 7.43 (m, 3H), 2.72 – 2.63 (m, 2H), 2.47 (s, 3H), 1.45 (m, 2H), 0.74 (t, J = 7.2 Hz, 3H).
13C NMR (DMSOꢀd6) δ 159.0, 144.5, 140.7, 135.8, 135.0, 133.2, 131.1, 128.7, 128.4, 128.0, 127.9, 127.2,
125.9, 34.3, 23.1, 21.2, 13.7. HRMS (ESI): m/z [M+H]+ calcd for C19H20N : 262.1590; found: 262.1600.
3-Cyclopropyl-6-methyl-2-phenylquinoline (4v)：
65% yield (167 mg); Yellow oil; IR νmax: 1598, 1489, 1432, 1343, 1266, 1130, 1073, 823, 760, 723, 698, 575
cm−1; 1H NMR (DMSOꢀd6) δ 7.89 – 7.82 (m, 2H), 7.69 (d, J = 7.8 Hz, 2H), 7.63 (s, 1H), 7.49 (t, J = 7.8 Hz,
3H), 7.45 (d, J = 7.2 Hz, 1H), 2.46 (s, 3H), 1.97 – 1.90 (m, 1H), 0.91 (d, J = 7.8 Hz, 2H), 0.81 (d, J = 4.8 Hz,
2H). 13C NMR (DMSOꢀd6) δ 159.1, 144.2, 140.5, 135.8, 134.6, 131.0, 130.5, 129.2, 128.3, 127.9, 127.2,
125.9, 21.2, 13.7, 9.9. HRMS (ESI): m/z [M+H]+ calcd for C19H18N :260.1434; found: 260.1438.
6-Methyl-3-((methylthio)methyl)-2-phenylquinoline (4w)：
48% yield (134 mg); Yellow oil; IR νmax: 2915, 1617, 1494, 1439, 1262, 1015, 823, 760, 700 cm−1; 1H NMR
(DMSOꢀd6) δ 8.25 (s, 1H), 7.88 (d, J = 8.4 Hz, 1H), 7.75 (s, 1H), 7.62 (d, J = 6.6 Hz, 2H), 7.58 (d, J = 8.4
Hz, 1H), 7.52 – 7.43 (m, 3H), 3.83 (s, 2H), 2.48 (s, 3H), 1.92 (s, 3H). 13C NMR (DMSOꢀd6) δ 158.6, 144.9,
140.0, 136.3, 136.1, 131.8, 129.6, 129.0, 128.4, 128.2, 128.1, 126.8, 126.1, 35.0, 21.2, 14.8. HRMS (ESI):
m/z [M+H]+ calcd for C18H18NS : 280.1155; found: 280.1157.
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6-Ethoxy-2,3-diphenylquinoline (5a)：
77% yield (250 mg); White crystalline; mp = 147ꢀ150 ℃; IR νmax: 1618, 1489, 1473, 1379, 1229, 1207,
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1180, 1041, 845, 760, 701 cm−1; H NMR (DMSOꢀd6) δ 8.21 (s, 1H), 7.96ꢀ7.96 (m, 1H), 7.39ꢀ7.23 (s, 2H),
7.28 (m, 10H), 4.14ꢀ4.15 (m, 2H), 1.41ꢀ1.39 (m, 3H). 13C NMR (DMSOꢀd6) δ 156.8, 154.9, 142.7, 140.3,
139.8, 136.5, 134.1, 130.2, 129.8, 129.5, 128.3, 128.0, 127.7, 127.2, 122.7, 106.0, 103.5, 63.6, 14.6. HRMS
(ESI): m/z [M+H]+ calcd for C23H20NO : 326.1539; found: 326.1546.
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2,3-Diphenyl-6-(trifluoromethyl)quinoline (5b)：
68% yield (238 mg); Yellow crystalline; mp = 88ꢀ91 ℃; IR νmax: 1631, 1321, 1291, 1161, 1122, 1061, 1006,
841, 676, 699, 634 cm−1; 1H NMR (DMSOꢀd6) δ 8.58 (s, 1H), 8.54 (s, 1H), 8.23 (d, J = 8.4 Hz, 1H), 7.99 (d,
J = 8.4 Hz, 1H), 7.37 (d, J = 6.6 Hz, 2H), 7.38ꢀ 7.24 (m, 8H). 13C NMR (DMSOꢀd6) δ 160.1, 147.5, 139.6,
139.0, 138.7, 135.2, 130.3, 129.9, 129.5, 128.5, 128.4, 127.9, 127.6, 126.9, 126.7, 126.4, 126.0, 125.1, 123.3.
HRMS (ESI): m/z [M+H]+ calcd for C22H15F3N : 350.1151; found: 350.1156.
6-(tert-butyl)-2,3-diphenylquinoline (5c)：
72% yield (242 mg); Red crystalline; mp = 139ꢀ142 ℃; IR νmax: 2961, 1614, 1495, 1363, 1259, 1023, 832,
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Hz, 1H), 7.34 (d, J = 6.6 Hz, 2H), 7.29ꢀ7.22 (m, 6H), 7.22 (d, J = 4.8 Hz, 2H), 1.38 (s, 9H). 13C NMR
(DMSOꢀd6) δ 156.9, 149.2, 145.2, 140.3, 139.7, 137.7, 133.8, 129.8, 129.5, 128.8, 128.3, 128.3, 127.9, 127.7,
127.2, 126.5, 122.7, 34.8, 30.9. HRMS (ESI): m/z [M+H]+ calcd for C25H24N: 338.1903; found: 338.1915.
6-Cyclohexyl-2,3-diphenylquinoline (5d)：
75% yield (271 mg); White crystalline; mp = 84ꢀ87 ℃; IR νmax: 2935, 2847, 1443, 908, 842, 768, 759, 699
cm−1; 1H NMR (DMSOꢀd6) δ 8.24 (s, 1H), 7.96 (d, J = 8.4 Hz, 1H), 7.77 (s, 1H), 7.63 (d, J = 8.4 Hz, 1H),
7.33 (d, J = 6.6 Hz, 2H), 7.30 – 7.22 (m, 6H), 7.20 – 7.19 (m, J = 3.2 Hz, 2H), 2.63 (t, J = 10.8 Hz, 1H), 1.83
(d, J = 10.8 Hz, 2H), 1.77 (d, J = 10.8 Hz, 2H), 1.68 (d, J = 11.4 Hz, 1H), 1.47ꢀ1.41 (m, 2H), 1.39 – 1.31 (m,
2H), 1.19ꢀ1.21 (m, 1H). 13C NMR (DMSOꢀd6) δ 156.7, 146.2, 145.6, 140.3, 139.7, 137.3, 133.8, 130.0,
129.8, 129.5, 128.6, 128.3, 127.8, 127.7, 127.2, 126.9, 124.2, 43.7, 33.8, 26.3, 25.6. HRMS (ESI): m/z
[M+H]+ calcd for C27H26N : 364.2060; found: 364.2088.
2,3-Diphenylbenzo[f]quinoline (5e)：
61% yield (201 mg); Brown crystalline; mp = 186ꢀ188 ℃; IR νmax: 1600, 1472, 1399, 1068, 1025, 831, 751,
697, 590, 507 cm−1; 1H NMR (CDCl3) δ 8.91 (s, 1H), 8.62 (d, J = 7.8 Hz, 1H), 8.09 (d, J = 9.0 Hz, 1H), 7.99
(d, J = 9.0 Hz, 1H), 7.93 (d, J = 7.2 Hz, 1H), 7.68ꢀ7.62 (m, 3H), 7.50ꢀ7.49 (m, 2H), 7.33ꢀ 7.31(m, 4H),
7.30ꢀ7.29 (m, 3H). 13C NMR (CDCl3) δ 157.4, 147.1, 140.3, 140.2, 134.3, 132.9, 132.9, 131.8, 131.0,
130.1, 129.8, 129.5, 128.7, 128.3, 128.1, 128.0, 127.2, 127.1, 124.1, 122.7. HRMS (ESI): m/z [M+H]+ calcd
for C25H18N: 332.1440; found: 332.1434.
2,3-Diphenylbenzo[h]quinoline (5f)：
66% yield (217 mg); White crystalline; mp = 127ꢀ130 ℃; IR νmax: 1400, 1022, 908, 802, 742, 699, 568 cm−1;
1H NMR (DMSOꢀd6) δ 9.23 (s, 1H), 8.44 (s, 1H), 8.06 (s, 1H), 7.99ꢀ7.94 (m, 2H), 7.77 (s, 2H), 7.51 (s, 2H),
7.34 (s, 8H). 13C NMR (DMSOꢀd6) δ 155.7, 144.2, 140.4, 139.6, 138.0, 134.5, 133.5, 130.6, 130.1, 129.6,
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128.4, 128.2, 128.1, 127.9, 127.4, 127.3, 125.4, 124.9, 124.0. HRMS (ESI): m/z [M+H]+ calcd for C25H18N:
332.1436; found: 332.1434.
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8,9-Diphenylphenaleno[1,9-gh]quinoline (5g)：
31% yield (124 mg); Brown crystalline; mp = 102ꢀ104 ℃; IR νmax: 1649, 1026, 1000, 531, 753, 691 cm−1;
1H NMR (CDCl3) δ 9.75 (d, J = 7.8 Hz, 1H), 8.52 (s, 1H), 8.42 (s, 1H), 8.36 (d, J = 7.8Hz, 1H), 8.27 (d, J =
7.8 Hz, 1H), 8.16 (d, J = 7.2 Hz, 1H), 8.10 (d, J = 6.6 Hz, 2H), 8.00 (d, J = 9.6 Hz, 2H), 7.71 (d, J = 6.0 Hz,
2H), 7.55 (s, 1H), 7.39 (m, 2H), 7.36 (m, 4H). 13C NMR (CDCl3) δ 156.5, 141.6, 140.7, 140.4, 137.8, 134.6,
132.2, 131.5, 131.3, 130.6, 130.6, 129.9, 129.0, 128.9, 128.7, 128.5, 128.4, 128.1, 127.9, 127.7, 127.6, 127.2,
126.5, 126.1, 125.5, 125.0, 124.9, 124.6, 123.9, 122.7. HRMS (ESI): m/z [M+H]+ calcd for C31H20N:
406.1590; found: 406.1593.
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7-Ethyl-2,3-diphenyl-7H-pyrido[2,3-c]carbazole (5h)：
74% yield (296 mg); Red crystalline; mp = 133ꢀ135 ℃; IR νmax: 1631, 1613, 1491, 1468, 1378, 1024, 1001,
827, 780, 769, 739, 701 cm−1; 1H NMR (DMSOꢀd6) δ 9.00 (s, 1H), 8.55 (d, J = 7.2 Hz, 1H), 8.22 (d, J = 7.8
Hz, 1H), 8.13 (d, J = 8.4 Hz, 1H), 7.81 (d, J = 7.2 Hz, 1H), 7.52 (s, 1H), 7.47 – 7.23 (m, 11H), 4.64 (d, J =
6.0 Hz, 2H), 1.38 (s, 3H). 13C NMR (DMSOꢀd6) δ 153.6, 143.1, 140.5, 140.0, 138.9, 137.0, 134.1, 132.2,
129.9, 128.4, 127.9, 127.8, 127.3, 124.8, 123.0, 122.6, 121.9, 120.2, 115.3, 113.2, 110.3, 37.3, 14.4. HRMS
(ESI): m/z [M+H]+ calcd for C29H23N2: 399.1856; found: 399.1860.
10,10-Dimethyl-2,3-diphenyl-10H-indeno[1,2-g]quinoline (5i)：
65% yield (258 mg); Brown oil; IR νmax: 1654, 1475, 1437, 1052, 1026, 1006, 825, 731, 626 cm−1; 1H NMR
(DMSOꢀd6) δ 8.42 (s, 1H), 8.38 (s, 1H), 8.22 (s, 1H), 7.98 (d, J = 4.8 Hz, 1H), 7.64 (d, J = 4.2 Hz, 1H), 7.45
– 7.37 (m, 4H), 7.36 – 7.25 (m, 8H), 1.57 (s, 6H). 13C NMR (DMSOꢀd6) δ 156.7, 156.0, 153.9, 146.9, 140.3,
139.7, 138.6, 137.6, 137.3, 133.4, 129.8, 129.6, 128.8, 128.3, 127.9, 127.7, 127.5, 127.2, 126.6, 123.3, 122.3,
121.0, 117.8, 46.4, 27.7. HRMS (ESI): m/z [M+H]+ calcd for C30H24N: 398.1908; found: 398.1903.
2,3,10,10-Tetraphenyl-10H-indeno[1,2-g]quinoline (5j)：
44% yield (230 mg); Orange crystalline; mp = 280ꢀ282 ℃; IR νmax: 1631, 1596, 1490, 1445, 1379, 911, 764,
747, 726, 700, 687 cm−1; 1H NMR (CDCl3) δ 8.23 (s, 1H), 8.19 (d, J = 7.2 Hz, 2H), 7.93 (d, J = 7.2 Hz, 1H),
7.50 (d, J = 7.2 Hz, 1H), 7.42 (d, J = 7.2 Hz, 3H), 7.37 – 7.33 (m, 1H), 7.28 (s, 7H), 7.25 (d, J = 5.4 Hz, 6H),
7.21 (d, J = 7.8 Hz, 5H). 13C NMR (CDCl3) δ 157.8, 153.5, 151.6, 147.4, 146.0, 140.3, 140.0, 139.8, 138.8,
137.5, 134.4, 129.9, 129.7, 128.9, 128.3, 128.2, 127.9, 127.8, 127.2, 127.0, 126.9, 126.7, 126.6, 120.9, 117.4,
65.3. HRMS (ESI): m/z [M+H]+ calcd for C40H28N: 522.2216; found: 522.2220.
3-Methyl-5,6-diphenyl-2H-pyrazolo[3,4-b]pyridine (5k)：
70% yield (201 mg); White crystalline; mp = 216ꢀ217 ℃; IR νmax:1615, 1488, 1440, 1384, 1215, 1134, 762,
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698, 631, 562 cm−1; H NMR (DMSOꢀd6) δ 13.31 (s, 1H), 8.20 (s, 1H), 7.34 – 7.21 (m, 8H), 7.19ꢀ 7.17(m,
2H), 2.54 (s, 3H). 13C NMR (DMSOꢀd6) δ 156.1, 151.7, 141.3, 140.6, 140.5, 131.6, 129.9, 128.9, 128.2,
127.8, 127.7, 126.7, 113.0, 12.4. HRMS (ESI): m/z [M+H]+ calcd for C19H16N3: 286.1339; found: 286.1341.
2,3,7,8-Tetraphenylpyrido[2,3-g]quinoline (5l)：
36% yield (87 mg); Orange crystalline; mp = 77ꢀ80 ℃; IR νmax: 1632, 1404, 1073, 1024, 831, 762, 698, 591
cm−1; 1H NMR (CDCl3) δ 8.90 (s, 2H), 8.36 (s, 2H), 7.53 (m, 4H), 7.33 (m, 16H). 13C NMR (CDCl3) δ 158.1,
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146.8, 139.9, 139.9, 134.9, 132.9, 132.2, 130.1, 129.8, 128.4, 128.2, 128.0, 127.5, 123.4. HRMS (ESI): m/z
[M+H]+ calcd for C36H25N2: 485.2012; found: 485.2015.
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2,2',3,3'-Tetraphenyl-6,6'-biquinoline (5m)：
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41% yield (115 mg); White crystalline; mp = 245ꢀ247 ℃; IR νmax: 1475, 1444, 1356, 1023, 1003, 907, 833,
763, 698, 591 cm−1; 1H NMR (DMSOꢀd6) δ 8.58 (s, 2H), 8.51 (s, 2H), 8.33 (d, J = 8.4 Hz, 2H), 8.24 (d, J =
8.4 Hz, 2H), 7.42 (d, J = 6.0 Hz, 4H), 7.36ꢀ7.31 (m, 16H). 13C NMR (DMSOꢀd6) δ 157.9, 146.2, 140.1,
139.6, 138.1, 137.5, 134.5, 129.9, 129.6, 129.2, 128.4, 128.2, 127.8, 127.4, 127.2, 125.9. HRMS (ESI): m/z
[M+H]+ calcd for C42H29N2: 561.2325; found: 561.2326.
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Bis(2,3-diphenylquinolin-6-yl)methane (5n):
64% yield (184 mg); Yellow crystalline; mp = 94ꢀ97 ℃; IR νmax: 2923, 1632, 1489, 1263, 1074, 1024, 800,
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764, 698 cm−1; H NMR (DMSOꢀd6) δ 8.31 (s, 2H), 8.03 (d, J = 7.8 Hz, 2H), 7.94 (s, 2H), 7.72 (d, J = 7.2
Hz, 2H), 7.35 (s, 4H), 7.29 (m, 12H), 7.24 (s, 4H), 4.40 (s, 2H). 13C NMR (DMSOꢀd6) δ 157.1, 145.6, 140.2,
139.6, 137.3, 134.1, 131.7, 129.8, 129.5, 129.0, 128.3, 127.9, 127.7, 127.2, 126.9. HRMS (ESI): m/z
[M+H]+ calcd for C43H31N2: 575.2482; found: 575.2473.
4-Methyl-8,9-diphenyl-2H-pyrano[2,3-f]quinolin-2-one (5o):
31% yield (112 mg); Yellow crystalline; mp = 203ꢀ205 ℃; IR νmax: 1725, 1631, 1604, 1378, 1276, 1157,
846, 699 cm−1; 1H NMR (DMSOꢀd6) δ 8.58 (s, 1H), 8.07 (d, J = 9.0 Hz, 1H), 7.99 (d, J = 9.0 Hz, 1H), 7.43
(d, J = 6.6 Hz, 2H), 7.38 – 7.29 (m, 8H), 6.57 (s, 1H), 2.57 (s, 3H). 13C NMR (CDCl3) δ 160.5, 160.4, 153.2,
149.9, 148.0, 139.6, 139.0, 135.5, 132.5, 129.9, 129.7, 128.5, 128.3, 128.0, 127.6, 125.4, 123.9, 117.4, 115.6,
114.6, 19.2. HRMS (ESI): m/z [M+H]+ calcd for C25H18NO2: 364.1332; found: 364.1331.
4-Methyl-7,8-diphenyl-2H-pyrano[3,2-g]quinolin-2-one (5p):
43% yield (156 mg); Yellow crystalline; mp = 235ꢀ237 ℃; IR νmax: 1731, 1630, 1447, 1210, 1061, 1023,
767, 701 cm−1; 1H NMR (DMSOꢀd6) δ 8.52 (s, 2H), 7.88 (s, 1H), 7.39 (d, J = 7.2 Hz, 2H), 7.39ꢀ7.30 (m, 6H),
7.27ꢀ7.26 (m, 2H), 6.51 (s, 1H), 2.53 (s, 3H). 13C NMR (DMSOꢀd6) δ 160.0, 159.4, 152.6, 152.4, 147.2,
139.7, 139.2, 138.3, 133.7, 129.8, 129.5, 128.4, 128.4, 127.8, 127.5, 126.0, 123.6, 120.5, 115.5, 112.9, 18.2.
HRMS (ESI): m/z [M+H]+ calcd for C25H18NO2: 364.1332; found: 364.1332.
3-(2,3-Diphenylquinolin-6-yl)-3-ethylpiperidine-2,6-dione (5q):
67% yield (282 mg); White oil; IR νmax: 1700, 1345, 1267, 1205, 1052, 1026, 1005, 841, 767, 706, 595, 582
cm−1; 1H NMR (DMSOꢀd6) δ 11.03 (s, 1H), 8.38 (s, 1H), 8.10 (d, J = 8.4 Hz, 1H), 7.92 (s, 1H), 7.80 (d, J =
8.4 Hz, 1H), 7.39 – 7.20 (m, 10H), 2.55ꢀ2.52 (m, 2H), 2.28ꢀ2.23 (m, 2H), 1.98 (m, 2H), 0.81 (m, 3H). 13C
NMR (DMSOꢀd6) δ 175.6, 172.8, 157.9, 145.7, 140.1, 139.5, 138.5, 137.9, 134.3, 129.8, 129.6, 129.3, 128.4,
128.3, 128.1, 127.8, 127.3, 126.6, 125.5, 50.5, 31.9, 29.2, 26.3, 9.1. HRMS (ESI): m/z [M+H]+ calcd for
C28H25N2O2:421.1911; found: 421.1915.
(1S,4R)-N-(2,3-diphenylquinolin-6-yl)-4,7,7-trimethyl-3-oxo-2-oxabicyclo[2.2.1]heptane-1-carboxamid
e (5r):
53% yield (252 mg); Brown oil; IR νmax: 1791, 1682, 1625, 1533, 1487, 1377, 1183, 1124, 1097, 1055, 1013,
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923, 761, 698, 583 cm−1; H NMR (DMSOꢀd6) δ 10.25 (s, 1H), 8.55 (s, 1H), 8.28 (s, 1H), 8.13 – 8.07 (m,
1H), 8.07 – 7.99 (m, 1H), 7.36 (s, 2H), 7.29ꢀ7.25 (m, 8H), 2.53 (s, 1H), 2.06 – 1.94 (m, 2H), 1.61ꢀ1.60 (m,
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1H), 1.06 (d, J = 16.9 Hz, 6H), 0.95 (s, 3H). 13C NMR (DMSOꢀd6) δ 178.0, 165.9, 156.5, 144.0, 140.2, 139.6,
137.3, 136.2, 134.2, 129.8, 129.6, 129.0, 128.3, 127.9, 127.7, 127.3, 127.0, 125.2, 117.2, 91.9, 54.7, 53.8,
30.2, 28.5, 16.6, 16.4, 9.6. HRMS (ESI): m/z [M+H]+ calcd for C31H29N2O3: 477.2173; found: 477.2176.
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Supporting Information
Crystallographic data and copies of the 1H and 13C NMR spectra are involved. This material is available free
of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
Eꢀmail: chwuax@mail.ccnu.edu.cn.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
We are grateful to the National Natural Science Foundation of China (Grant Nos. 21472056 and 21602070)
and the Fundamental Research Funds for the Central Universities (CCNU15ZX002 and CCNU16A05002)
for financial support. This work was also supported by the 111 Project B17019. We acknowledge an
Excellent Doctoral Dissertation Cultivation Grant from Central China Normal University (2015YBYB089).
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