A facile and efficient one-pot synthesis of substituted quinolines from α-arylamino ketones under vilsmeier conditions

Article abstract of DOI:10.1002/ejoc.200900430

An efficient: one-pot synthesis of substituted, quinolines from, α-arylamino ketones in the presence of PBr₃ in DMF has been developed. This general protocol provides a novel and facile access to substituted quinolines by sequential Vilsmeier-H

Full text of DOI:10.1002/ejoc.200900430

FULL PAPER
DOI: 10.1002/ejoc.200900430
A Facile and Efficient One-Pot Synthesis of Substituted Quinolines from
α-Arylamino Ketones Under Vilsmeier Conditions
Yan Wang,[a,b] Xin Xin,[a,b] Yongjiu Liang,[b] Yingjie Lin,*[a] Rui Zhang,[b] and
Dewen Dong*[b]
Keywords: Heterocycles / Cyclization / Aromatization / Amino ketones / Formylation / Vilsmeier–Haack reaction
An efficient one-pot synthesis of substituted quinolines from
α-arylamino ketones in the presence of PBr3 in DMF has
been developed. This general protocol provides a novel and
facile access to substituted quinolines by sequential Vils-
meier–Haack reaction, intramolecular cyclization and aroma-
tization reactions of α-arylamino ketones. PBr3 plays a dual
role in the quinoline synthesis: as a key component of the
Vilsmeier reagent (PBr3/DMF) and as a reducing reagent.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2009)
documented.[9] The synthesis of functionalized quinolines
by the “Vilsmeier approach” has been explored through the
study of the reaction of enamines,[10] N-arylacetamides
(Scheme 1)[11] or α-oxo ketene N,S-acetals[12] with Vilsmeier
reagents. Recently, Katritzky and Arend reported a highly
regioselective one-pot synthesis of 2,3-dialkyl/fused quino-
lines by cyclocondensation of imines with a novel Vilsmeier
reagent derived from N-(trimethylsilyl)benzotriazole, DMF
and SOCl2.[13] As an alternative, a “reverse Vilsmeier ap-
proach” has also been developed by ring-closure of the
Vilsmeier reagent derived from N-aryl-N-methylformamide
with electron-rich olefins to give N-methylquinolinium
salts.[14]
Introduction
Quinolines and related heterocyclic systems represent
privileged moieties in medicinal chemistry and are ubiqui-
tous subunits associated with biologically active natural
products and synthetic organic compounds.[1–3] Their phar-
macological importance and utility as building-blocks in
organic synthesis have encouraged considerable research ac-
tivity towards the synthesis of suitably substituted quinoline
rings. Intensive research has generated numerous synthetic
approaches, including the conventional named methods of
Combes, Skraup, Döbner–Von Miller, Conrad–Limpach,
Pfitzinger, Friedländer and Povarov syntheses,[4,5] and the
homogeneous metal-catalysed heteroannulation of acyclic
precursors.[6,7] Although each of these approaches repre-
sents an important advance towards the objective of a gene-
ral method for the synthesis of quinolines, some of them
suffer from significant limitations in terms of the non-avail-
ability of precursors, multistep procedures, harsh condi-
tions, low yields, or poor chemo- and regioselectivity. In
light of these, simple and efficient methodologies for the
construction of the quinoline skeleton are still in demand.
On the other hand, the Vilsmeier–Haack reaction, owing
to the mild reaction conditions, commercial availability of
the reagents and improved understanding of the reaction
mechanism, has been widely used for the formylation of
activated aromatic and carbonyl compounds.[8] The versa-
tile reactivity of carbonyl compounds with halomethylenei-
minium salts and subsequent cyclization to heterocyclic
compounds induced by the Vilsmeier reagent have been well
Scheme 1. Meth-Cohn quinoline synthesis.
In our recent work we have demonstrated the utility of
the Vilsmeier reagent in the synthesis of functionalized het-
erocycles, such as substituted 2H-pyrans,[15] pyridines,[16]
1H-pyrazoles[17] and pyridin-2(1H)-ones.[18] Thus, as a con-
tinuation of previous work and following on our research
interest in the synthesis of highly valuable heterocycles, we
have prepared a series of α-arylamino ketones and exam-
ined their reactivity towards different Vilsmeier reagents. As
a result, we report herein a facile and efficient synthesis of
substituted quinolines 2 by Vilsmeier–Haack reactions of
the readily available α-arylamino ketones 1.
[a] Department of Chemistry, Jilin University,
Changchun, P. R. China
[b] Changchun Institute of Applied Chemistry, Chinese Academy
of Sciences,
Results and Discussion
Changchun 130022, P. R. China
Fax: +86-431-85693057
Substrates 1 were prepared from commercially available
2-bromo-1-arylethanones and arylamines in the presence of
E-mail: dwdong@ciac.jl.cn
Eur. J. Org. Chem. 2009, 4165–4169
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Y. Wang, X. Xin, Y. Liang, Y. Lin, R. Zhang, D. Dong
FULL PAPER
K2CO3 in ethanol at room temperature in excellent yields other Vilsmeier reagent, POCl3/DMF, at 120 °C for 6.0 h
according to the previously reported procedure.[19] With (Table 1, entry 8).
compounds 1a–q in hand, we selected 1-phenyl-2-(phen-
ylamino)ethanone (1a) as a model compound to examine
its reaction behaviour under Vilsmeier conditions.
Table 1. Reaction of 1-phenyl-2-(phenylamino)ethanone (1a) under
Vilsmeier conditions.
Thus, the reaction of 1a with Vilsmeier reagent PBr3/
DMF (4.0 equiv.) was first attempted at room temperature.
The resulting mixture quickly became viscous and finally
turned into a brown solid. Unfortunately no product pre-
dominated, as indicated by TLC. When 1a was treated with
PBr3/DMF (4.0 equiv.) at 80 °C, the mixture turned into a
solution. The reaction proceeded smoothly and furnished a
product after work-up and purification by column
chromatography of the resulting mixture. The product was
characterized as 3-phenylquinoline (2a; 48% yield) on the
basis of its spectral and analytical data (Table 1, entry 2).
The optimization of the reaction conditions, including reac-
tion temperature and the feed ratio of 1a to PBr3/DMF,
was then investigated. A series of experiments revealed that
2.0 equiv. of PBr3/DMF was effective for the synthesis of
2a; the optimal results were obtained when the reaction of
1a with 4.0 equiv. of PBr3/DMF was performed at 120 °C
Entry Vilsmeier reagent
[equiv.]
Temp. [°C] Time [h] % Yield[a]
1
2
3
4
5
6
7
8
PBr3/DMF (4.0)
PBr3/DMF (4.0)
PBr3/DMF (4.0)
PBr3/DMF (4.0)
PBr3/DMF (3.0)
PBr3/DMF (2.0)
PBr3/DMF (1.0)
POCl3/DMF (4.0)
r.t.
80
10.0
10.0
6.0
3.5
6.0
6.0
6.0
6.0
0
48
51
64
59
47
15
0
100
120
120
120
120
120
[a] Isolated yield of 2a.
Under conditions identical to those used for the prepara-
for 3.5 h, which gave a yield of 2a of 64% (Table 1, entry 4). tion of 2a in Table 1, entry 4, a series of reactions of α-
Note that 2a was not obtained when subjecting 1a to an- arylamino ketones 1 with PBr3/DMF (4.0 equiv.) were con-
Table 2. Synthesis of substituted quinolines 2 by the Vilsmeier–Haack reaction of α-arylamino ketones 1.[a]
[a] Reagents and conditions: PBr3/DMF (4.0 equiv.), 120 °C, 3.5–5.0 h. [b] Isolated yield of 2; the number in brackets is a reference to
known compounds of 2.
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Eur. J. Org. Chem. 2009, 4165–4169

Synthesis of Substituted Quinolines from α-Arylamino Ketones
ducted at 120 °C and some of the results are summarized reaction, intramolecular cyclization reactions and an aro-
in Table 2. The efficiency of the cyclization proved to be matization reaction. The simplicity of execution, ready
suitable for α-arylamino ketones 1b–m, which afforded the availability of substrates and potentially important use of
corresponding substituted quinolines 2b–m in good yields the products make this synthetic protocol attractive for aca-
(Table 2, entries 2–13). The versatility of the quinoline syn- demic research and practical applications. Further studies
thesis was evaluated by performing the reaction with 1-aryl- towards expanding the scope and synthetic application of
2-(naphthalen-1-ylamino)ethanones 1n–p (Table 2, en- this protocol are in progress.
tries 14–16). When 2-(m-toluidino)-1-phenylethanone (1q)
was subjected to identical conditions, the reaction furnished
a product that was characterized as 7-methyl-3-phenylquin-
oline (2q; Table 2, entry 17). We could not isolate its re-
Experimental Section
General: All reagents were purchased from commercial sources and
gioisomer, which might be present in trace amounts in the
used without treatment unless otherwise indicated. 1H and 13C
reaction mixture. The results indicate that the quinoline
NMR spectra were recorded at 25 °C at 500 (or 300) and 125 (or
75) MHz, respectively, using TMS as the internal standard. IR
synthesis exhibits high regioselectivity.
On the basis of all the results obtained, a plausible
spectra (KBr) were recorded with a FTIR spectrometer in the range
mechanism for the synthesis of substituted quinolines 2 is
presented in Scheme 2. Mediated by Vilsmeier reagent PBr3/
DMF, substrate 1 is first converted into enolate A followed
by a formylation to give intermediate B, which undergoes
an intramolecular cyclization to generate iminium ion
C.[12a–12c,21] Subsequent intramolecular cyclization of C
leads to the cyclic phosphonium intermediate D,[20] which
is then aromatized to furnish a substituted quinoline of type
of 400–4000 cm–1. Mass spectra were recorded with a LCMsD
mass spectrometer.
Typical Procedure for the Synthesis of Substituted Quinolines 2 (with
2a as an example): The Vilsmeier reagent was prepared by adding
PBr3 (8.0 mmol, 0.76 mL) dropwise to ice-cold dry DMF (5 mL)
whilst stirring. The mixture was then stirred for 10–15 min at 0 °C.
Compound 1a (2.0 mmol, 0.422 g) was added as a solution in DMF
(20 mL) to the above Vilsmeier reagent. Then the mixture was
2. Clearly, the reagent PBr3 plays a dual role in the quino- heated to 120 °C and stirred for 3.5 h. After the starting material
had been consumed (monitored by TLC), the reaction mixture was
poured into a saturated aqueous NaHCO3 solution (50 mL). The
mixture was extracted with dichloromethane (3ϫ30 mL), the com-
bined organic phase was washed with water (2ϫ30 mL), dried with
MgSO4, filtered and concentrated in vacuo. The crude product was
purified by flash chromatography (silica gel, petroleum ether/ethyl
acetate, 10:1) to give 2a as a viscous liquid (0.262 g, 64% yield).
line synthesis process: one is as a key component of the
Vilsmeier reagent (with DMF) and the other is as a reduc-
ing reagent, rather than a halogenated reagent. In fact, ter-
valent phosphorus compounds (PX3) such as trialkyl- or
triarylphosphanes and diethyl chlorophosphite have been
reported as useful reducing reagents in synthetic chemis-
try.[21] The major driving force for these reactions is the for-
mation of a P=O bond and the release of 120–150 kcal/mol.
Therefore, it is not hard to understand why the quinoline
synthesis fails when subjecting 1 to another Vilsmeier rea-
gent such as POCl3/DMF.
Physical Data of the Compounds Isolated
2a: Yellowish oil. 1H NMR (CDCl3, 500 MHz): δ = 7.45 (t, J =
7.5 Hz, 1 H), 7.54 (t, J = 8.0 Hz, 2 H), 7.59 (t, J = 7.0 Hz, 1 H),
7.74 (t, J = 6.5 Hz, 3 H), 7.89 (d, J = 8.0 Hz, 1 H), 8.15 (d, J =
8.5 Hz, 1 H), 8.31 (s, 1 H), 9.20 (s, 1 H) ppm. 13C NMR (CDCl3,
125 MHz): δ = 127.0, 127.4, 128.0, 128.1, 128.8, 128.9, 129.2, 129.4,
133.3, 133.8, 137.8, 147.3, 149.9 ppm. C15H11N (205.25): calcd. C
87.77, H 5.40, N 6.82; found C 87.68, H 5.29, N 6.75.
1
2b: Yellowish oil. H NMR (CDCl3, 500 MHz): δ = 2.58 (s, 3 H),
7.46 (t, J = 7.5 Hz, 1 H), 7.53–7.58 (m, 3 H), 7.66 (s, 1 H), 7.73 (d,
J = 8.0 Hz, 2 H), 8.04 (d, J = 8.5 Hz, 1 H), 8.24 (d, J = 1.0 Hz, 1
H), 9.13 (s, 1 H) ppm. 13C NMR (CDCl3, 125 MHz): δ = 21.6,
126.7, 127.3, 128.0, 129.1, 131.7, 132.6, 133.7, 136.8, 138.0, 145.9,
149.0 ppm. C16H13N (219.28): calcd. C 87.64, H 5.98, N 6.39;
found C 87.66, H 5.86, N 6.32.
1
2c: Yellowish oil. H NMR (CDCl3, 500 MHz): δ = 3.96 (s, 3 H),
7.15 (s, 1 H), 7.38 (d, J = 9.5 Hz, 1 H), 7.44 (t, J = 7.5 Hz, 1 H),
7.53 (t, J = 8.0 Hz, 2 H), 7.71 (d, J = 7.5 Hz, 2 H), 8.03 (d, J =
9.5 Hz, 1 H), 8.21 (s, 1 H), 9.03 (s, 1 H) ppm. 13C NMR (CDCl3,
125 MHz): δ = 55.6, 105.3, 122.2, 127.4, 128.0, 129.1, 130.6, 132.1,
134.1, 138.0, 143.4, 147.4, 158.1 ppm. C16H13NO (235.28): calcd.
C 81.68, H 5.57, N 5.95; found C 81.53, H 5.51, N 5.87.
Scheme 2. Proposed mechanism for the synthesis of quinolines 2.
1
2d: Yellowish oil. H NMR (CDCl3, 300 MHz): δ = 7.45–7.56 (m,
4 H, Ar-H), 7.63–7.71 (m, 2 H), 7.86 (s, 1 H), 8.07 (d, J = 9.0 Hz,
1 H), 8.20 (s, 1 H), 9.17 (s, 1 H) ppm. 13C NMR (CDCl3, 75 MHz):
δ = 126.6, 127.4, 128.4, 128.7, 128.9, 129.2, 130.2, 130.8, 132.2,
134.7, 137.3, 145.6, 150.1 ppm. C15H10ClN (239.70): calcd. C
Conclusions
We have described a facile and efficient synthesis of sub-
stituted quinolines of type 2 from α-arylamino ketones 1 in
the presence of PBr3/DMF by sequential Vilsmeier–Haack 75.16, H 4.21, N 5.84; found C 75.31, H 4.18, N 5.91.
Eur. J. Org. Chem. 2009, 4165–4169
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4167

Y. Wang, X. Xin, Y. Liang, Y. Lin, R. Zhang, D. Dong
FULL PAPER
2e: Yellowish oil. H NMR (CDCl3, 300 MHz): δ = 2.85 (s, 3 H),
1
55.5, 105.1, 114.6, 121.9, 128.5, 129.1, 130.4, 130.5, 131.3, 133.7,
7.41–7.47 (m, 2 H), 7.50–7.57 (m, 3 H), 7.72 (t, J = 7.0 Hz, 3 H),
143.1, 147.3, 158.0, 159.7 ppm. IR (KBr, neat): ν = 676, 833, 1022,
˜
8.26 (d, J = 2.0 Hz, 1 H), 9.12 (d, J = 2.0 Hz, 1 H) ppm. 13C NMR 1247, 1286, 1515, 1606 cm–1. C17H15NO2 (265.31): calcd. C 76.96,
(CDCl3, 75 MHz): δ = 18.1, 126.1, 126.8, 127.4, 128.0, 129.2, 129.6,
133.5, 133.6, 137.0, 138.0, 146.4, 148.7 ppm. C16H13N (219.28):
calcd. C 87.64, H 5.98, N 6.39; found C 87.56, H 5.87, N 6.49.
H 5.70, N 5.28; found C 76.76, H 5.76, N 5.20.
1
2m: White solid, m.p. 141–143 °C. H NMR (CDCl3, 300 MHz): δ
= 2.51 (s, 3 H), 2.82 (s, 3 H), 3.89 (s, 3 H), 6.97 (d, J = 7.5 Hz, 1
H), 7.06 (d, J = 8.1 Hz, 2 H), 7.41 (s, 1 H), 7.48 (s, 1 H), 7.65 (d,
J = 7.8 Hz, 2 H), 7.94 (d, J = 8.1 Hz, 1 H), 8.16 (s, 1 H), 9.13 (s,
1 H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 18.0, 21.6, 55.4, 113.9,
114.3, 114.6, 124.7, 128.4, 131.7, 132.1, 132.4, 133.1, 136.5,
147.7 ppm. C18H17NO (263.33): calcd. C 82.10, H 6.51, N 5.32;
found C 82.40, H 6.43, N 5.43.
1
2f: Yellowish oil. H NMR (CDCl3, 500 MHz): δ = 2.50 (s, 3 H),
2.81 (s, 3 H), 7.42 (t, J = 7.5 Hz, 2 H), 7.48–7.52 (m, 3 H), 7.69–
7.71 (m, 2 H), 8.17 (d, J = 2.0 Hz, 1 H), 9.13 (d, J = 2.0 Hz, 1
H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 18.0, 21.6, 124.9, 127.4,
127.9, 128.2, 129.0, 129.1, 132.0, 133.0, 133.5, 136.4, 136.6, 138.2,
147.8 ppm. C17H15N (233.31): calcd. C 87.52, H 6.48, N 6.00;
found C 87.28, H 6.58, N 5.90.
1
2n: White solid, m.p. 196–197 °C. H NMR (CDCl3, 500 MHz): δ
1
= 7.52 (d, J = 8.5 Hz, 2 H), 7.69–7.79 (m, 6 H), 7.86 (d, J = 9.0 Hz,
1 H), 7.94 (d, J = 8.0 Hz, 1 H), 8.31 (s, 1 H), 9.22 (s, 1 H), 9.29 (d,
J = 7.5 Hz, 1 H) ppm. 13C NMR (CDCl3, 125 MHz): δ = 124.3,
125.4, 126.1, 127.3, 127.9, 128.3, 128.4, 128.6, 129.4, 131.2, 133.2,
2g: White solid, m.p. 149–150 °C. H NMR (CDCl3, 500 MHz): δ
= 7.51 (d, J = 8.0 Hz, 2 H), 7.61 (t, J = 7.5 Hz, 1 H), 7.66 (d, J =
8.0 Hz, 2 H), 7.75 (t, J = 7.5 Hz, 1 H), 7.89 (d, J = 8.5 Hz, 1 H),
8.15 (d, J = 8.5 Hz, 1 H), 8.29 (s, 1 H), 9.15 (s, 1 H) ppm. 13C
NMR (CDCl3, 125 MHz): δ = 127.2, 127.9, 128.0, 128.6, 129.2,
129.4, 129.6, 133.2, 134.4, 136.3, 149.5, 150.0 ppm. IR (KBr, neat):
133.3, 133.6, 134.3, 136.4, 145.7, 147.5 ppm. IR (KBr, neat): ν =
˜
533, 548, 745, 815, 948, 1012, 1094, 1447 cm–1. C19H13N (255.31):
calcd. C 89.38, H 5.13, N 5.49; found C 89.17, H 5.18, N 5.35.
ν = 542, 672, 748, 824, 1096, 1356, 1491, 1559 cm–1. C H ClN
˜
15 10
(239.70): calcd. C 75.16, H 4.21, N 5.84; found C 75.40, H 4.15, N
5.73.
1
2o: White solid, m.p. 193–194 °C. H NMR (CDCl3, 500 MHz): δ
= 7.52 (d, J = 8.0 Hz, 2 H), 7.69–7.79 (m, 5 H), 7.87 (d, J = 8.5 Hz,
1 H), 7.94 (d, J = 7.5 Hz, 1 H), 8.32 (d, J = 1.5 Hz, 1 H), 9.22 (s,
1 H), 9.29 (d, J = 7.5 Hz, 1 H) ppm. 13C NMR (CDCl3, 125 MHz):
δ = 124.3, 125.4, 126.1, 127.3, 127.9, 128.3, 128.4, 128.6, 129.4,
131.2, 133.2, 133.3, 133.6, 134.3, 136.4, 145.7, 147.5 ppm. IR (KBr,
1
2h: White solid, m.p. 151–152 °C. H NMR (CDCl3, 500 MHz): δ
= 2.56 (s, 3 H), 7.49 (d, J = 8.5 Hz, 2 H), 7.56 (t, J = 7.5 Hz, 1 H),
7.63 (t, J = 6.0 Hz, 3 H), 8.02 (d, J = 9.0 Hz, 1 H), 8.17 (d, J =
1.0 Hz, 1 H), 9.06 (d, J = 1.5 Hz, 1 H) ppm. 13C NMR (CDCl3,
125 MHz): δ = 21.6, 126.7, 127.9, 128.6, 128.9, 129.3, 131.9, 132.5,
neat): ν = 548, 762, 745, 835, 1012, 1094, 1492, 1513 cm–1.
˜
C19H12ClN (289.76): calcd. C 78.76, H 4.17, N 4.83; found C 78.89,
H 4.08, N 4.76.
132.6, 134.2, 136.5, 137.1, 146.0, 148.6 ppm. IR (KBr, neat): ν =
˜
459, 515, 827, 917, 1093, 1341, 1490 cm–1. C16H12ClN (253.73):
calcd. C 75.74, H 4.77, N 5.52; found C 75.62, H 4.68, N 5.57.
MS: calcd. for C16H12ClN [M + 1]+ 253.0; found 254.0.
1
2p: White solid, m.p. 133–134 °C. H NMR (CDCl3, 500 MHz): δ
= 3.90 (s, 3 H), 7.09 (d, J = 8.5 Hz, 2 H), 7.70–7.78 (m, 3 H), 7.85
(m, 2 H), 7.93 (d, J = 8.5 Hz, 2 H), 8.30 (d, J = 1.5 Hz, 1 H), 9.24
(d, J = 2.0 Hz, 1 H), 9.28 (d, J = 8.0 Hz, 1 H) ppm. 13C NMR
(CDCl3, 75 MHz): δ = 55.4, 113.6, 114.6, 124.2, 125.5, 127.1, 127.8,
128.0, 128.1, 128.4, 130.6, 132.6, 133.4, 146.9, 147.7, 152.1, 157.3,
159.2 ppm. C20H15NO (285.34): calcd. C 84.19, H 5.30, N 4.91;
found C 84.28, H 5.27, N 4.83.
1
2i: White solid, m.p. 139–140 °C. H NMR (CDCl3, 500 MHz): δ
= 3.96 (s, 3 H), 7.13 (d, J = 2.5 Hz, 1 H), 7.38–7.40 (q, J = 7.5 Hz,
1 H), 7.50 (d, J = 8.5 Hz, 2 H), 7.64 (d, J = 8.5 Hz, 2 H), 8.03 (d,
J = 9.0 Hz, 1 H), 8.18 (d, J = 1.5 Hz, 1 H), 8.98 (d, J = 2.5 Hz, 1
H) ppm. 13C NMR (CDCl3, 125 MHz): δ = 55.6, 105.2, 122.5,
128.6, 129.0, 129.3, 130.5, 132.1, 132.9, 134.3, 136.4, 143.5, 146.9,
158.2 ppm. IR (KBr, neat): ν = 506, 829, 1091, 1215, 1455, 1492,
1
˜
2q: Yellowish oil. H NMR (CDCl3, 300 MHz): δ = 2.59 (s, 3 H),
1683 cm–1. C16H12ClNO (269.73): calcd. C 71.25, H 4.48, N 5.19;
found C 71.30, H 4.43, N 5.29. MS: calcd. C16H12ClNO [M + 1]+
269.0; found 270.0.
7.43 (t, J = 7.2 Hz, 2 H), 7.52 (t, J = 7.5 Hz, 2 H), 7.70–7.79 (m,
3 H), 7.91 (s, 1 H), 8.25 (d, J = 2.4 Hz, 1 H), 9.14 (d, J = 2.1 Hz,
1 H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 21.9, 127.5, 127.56,
127.6, 127.9, 128.0, 128.2, 129.1, 129.2, 133.0, 138.0, 139.7, 147.6,
149.8 ppm. C16H13N (219.28): calcd. C 87.64, H 5.98, N 6.39;
found C 87.89, H 5.92, N 6.46.
1
2j: White solid, m.p. 129–131 °C. H NMR (CDCl3, 500 MHz): δ
= 2.52 (s, 3 H), 2.81 (s, 3 H), 7.43 (s, 1 H), 7.49 (d, J = 8.5 Hz, 3
H), 7.64 (d, J = 8.5 Hz, 2 H), 8.16 (s, 1 H), 9.09 (d, J = 1.0 Hz, 1
H) ppm. 13C NMR (CDCl3, 75 MHz): δ = 18.0, 21.6, 120.3, 124.8,
128.6, 129.3, 132.2, 132.8, 134.1, 136.8, 144.5, 147.4 ppm.
C17H14ClN (267.75): calcd. C 76.26, H 5.27, N 5.23; found C 76.24,
H 5.35, N 5.13.
Acknowledgments
Financial support of this research by the National Natural Science
Foundation of China (20872136) is greatly acknowledged.
1
2k: White solid, m.p. 137–139 °C. H NMR (CDCl3, 500 MHz): δ
= 2.56 (s, 3 H), 3.89 (s, 3 H), 7.06 (d, J = 7.5 Hz, 2 H), 7.53 (d, J
= 7.5 Hz, 1 H), 7.62 (s, 1 H), 7.65 (d, J = 7.5 Hz, 2 H), 8.01 (d, J
= 7.5 Hz, 1 H), 8.16 (s, 1 H), 9.09 (d, J = 1.5 Hz, 1 H) ppm. 13C
NMR (CDCl3, 125 MHz): δ = 21.6, 55.4, 114.6, 126.7, 127.0, 128.4,
128.7, 130.4, 131.4, 131.8, 133.4, 136.8, 145.6, 148.9, 160.0 ppm.
C17H15NO (249.31): calcd. C 81.90, H 6.06, N 5.62; found C 81.78,
H 6.15, N 5.57.
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Received: April 18, 2009
Published Online: July 7, 2009
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