The first cerium (IV) ammonium nitrate (CAN)-catalyzed friedlaender synthesis of quinolines in ionic liquid

Article abstract of DOI:10.3987/COM-09-11865

A mild and efficient route for the synthesis of quinolines and polycyclic quinolines utilizing cerium (IV) ammonium nitrate (CAN) as a novel catalyst via Friedlaender annulation in ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF6]

Full text of DOI:10.3987/COM-09-11865

HETEROCYCLES, Vol. 81, No. 3, 2010
689
HETEROCYCLES, Vol. 81, No. 3, 2010, pp. 689 - 698. © The Japan Institute of Heterocyclic Chemistry
Received, 31st October, 2009, Accepted, 7th January, 2010, Published online, 8th January, 2010
DOI: 10.3987/COM-09-11865
THE FIRST CERIUM (IV) AMMONIUM NITRATE (CAN)-CATALYZED
FRIEDLÄNDER SYNTHESIS OF QUINOLINES IN IONIC LIQUID
Rei-Sheu Hou,a* Huey-Min Wang,a Iou-Jiun Kang,b Hau-Dung Du,c and
Ling-Ching Chen c*
a Chung Hwa University of Medical Technology, Tainan 717, Taiwan, R.O.C
b
Division of Biotechnology and Pharmaceutical Research, National Health
Research Institutes, Miaoli County 350, Taiwan, R.O.C.
c Graduate Institute of Pharmaceutical Sciences, College of Pharmacy, Kaohsiung
Medical University, Kaohsiung 807, Taiwan, R.O.C.
E-mail: m715003@cc.kmu.edu.tw
Abstract - A mild and efficient route for the synthesis of quinolines and
polycyclic quinolines utilizing cerium (IV) ammonium nitrate (CAN) as a novel
catalyst via Friedländer annulation in ionic liquid 1-n-butyl-3-methylimidazolium
hexafluorophosphate [Bmim][PF6] under mild conditions was described.
Quinoline derivatives have been well known not only in medicinal chemistry, because of their wide
occurrence in natural products1 and drugs,2 but also in polymer chemistry, electronics and optoelectronics
for their excellent mechanical properties.3 Versatile methods for the synthesis of the quinoline ring
system have been developed.4
Friedländer annulation is one of the most simple and straightforward approaches for the synthesis of
quinoline derivatives. Friedländer synthesis can be catalysed by strong acids or bases, and may take place
without a catalyst at high temperature. Brønsted acids like hydrochloric acid, sulfuric acid,
p-toluenesulfonic acid and phosphoric acid were widely used as catalysts. However, many of these
methods require harsh reaction conditions and lead to several side reactions. Recently, Lewis acids such
5
as ZnCl2, SnCl2, Bi(OTf)3, Sc(OTf)3, silver phosphotungstate, sodium fluoride, AuCl3 have been
reported to be effective for the synthesis of quinolines. However, many of these procedures suffered from
harsh reaction conditions, low yields, difficulties in work up, and the use of stoichiometric and/or
relatively expensive reagents. Furthermore, the synthesis of quinolines in general have been carried out in
polar solvents such as acetonitrile, THF, DMF and DMSO leading to complex isolation and recovery
procedures. Since quinoline derivatives are increasingly useful and important in pharmaceuticals and
industry, the development of simple, efficient and eco-benign protocol is still desirable.

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HETEROCYCLES, Vol. 81, No. 3, 2010
Room temperature ionic liquids (RTIL) are liquids that are composed entirely of ions. In fact, ionic
liquids can now be produced which remain liquid at room temperature and appear to be undemanding and
inexpensive to manufacture.6 Ionic liquids offer an attractive alterative to conventional organic liquids for
clean synthesis, as they are easy to recycle, lack flammability, and possess effectively no vapour pressure.
Compared with classical molecular solvents, the ionic liquids are environmentally benign reaction
media.7
Recently, there has been growing considerable interest in the use of lanthanide reagents, cerium (IV)
ammonium nitrate (CAN) is the most notable one electron oxidant and has been utilized extensively for a
broad variety of oxidative transformations in organic chemistry.8 Additionally, many advantages such as
inexpensiveness, ecofriendly nature, uncomplicated handling and high reactivity makes CAN a potent
catalyst in organic syntheses. More recently, studies have also revealed protocols for mild conditions, fast
conversions and convenient work-up procedures using CAN, to make it a powerful tool in chemistry
under green and safer approaches. Besides this, CAN is able to catalyze various organic transformations
not only based on the Lewis acidic property, but also with electron transfer capability. In this paper, we
report the use of CAN as catalyst for the synthesis of quinolines via Friedländer annulation in ionic liquid
1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) under mild conditions.
Treatment of 2-aminobenzophenone (1a) and ethyl acetoacetate (2a) with CAN as catalyst in ionic
liquid [Bmim][PF6] at 60 °C for 30 min caused cyclodehydration to give ethyl
2-methyl-4-phenylquinoline-3-carboxylate (3a) in 92% yield (Scheme 1). When the reaction is conducted
in a conventional solvent, such as acetonitrile, the preparation of 3a needs refluxing for 3 h.
Ph
Ph
O
R2
R1
R
R
CAN
R2
O
+
R1
NH2
R = H, Cl
[Bmim][PF6], 60 °C, 30 min
N
1
3
2
PF6
a, R = H
b. R = Cl
[Bmim][PF6] =
N
N
Scheme 1
This method is equally effective for both cyclic and acyclic ketones. Cyclic ketones and various
1,3-diketones such as acetyl acetone and 5,5-dimethylcyclohexanedione reacted efficiently with
2-aminobenzophenones to give the corresponding substituted quinolines. The results are given in Table 1.
Interestingly, bicyclic ketone such as α-tetralone (2g) and 2-norbornanone (2h) also underwent smooth
condensation with 2-aminobenzophenones to afford the respective polycyclic quinolines (3g, 3h) with
good yields (Figure 1). When the reaction is conducted in ionic liquid [Bmim][PF6], and sulfuric acid as
catalyst, the preparation of 3p needs heating at 80 °C for 5 h.

HETEROCYCLES, Vol. 81, No. 3, 2010
691
Ph
Ph
N
N
3h
3g
Figure 1
The products were characterized by 1H, 13C NMR, IR and mass spectroscopic data. This method is clean
and free from side reactions such as self-condensation of ketones which are normally observed under
basic conditions. Unlike reported methods, the present protocol does not require high temperature or
drastic conditions to produce quinoline derivatives. Furthermore, the condensation of
2-aminobenzophenone (1a) with ethyl acetoacetate (2a) in the presence of concd H2SO4 afforded the
quinoline product in only 65% yield (entry 1).
In conclusion, we have demonstrated a simple and efficient procedure for the synthesis of quinolines,
including polycyclic quinolines, using CAN as catalyst. The significant features of this method include
operational simplicity, improved reaction rates, high yields of products and avoidance of the use of
hazardous acids or bases.
ACKNOWLEDGEMENT
We gratefully acknowledge the National Council Science of Republic of China for financial support of
this work.
EXPERIMENTAL
All melting points are uncorrected. The IR spectra were recorded on a Shimadzu IR-27 G
1
spectrophotometer. H NMR and 13C NMR spectra were recorded on a Varian Unity Plus 400 MHz.
Chemical shifts () were measured in ppm with respect to TMS. MS were obtained on a JEOL JMS
D-300 instrument
General procedure for the preparation quinoline (3)
A mixture of 2-aminobenzophenone (1.0 mmol), ketone (1.3 mmol) and CAN (0.05 mmol) in
[Bmim][PF6] (2 mL) ionic liquid was stirred at 60 °C for 30 min to complete the reaction. Subsequently,
the reaction mixture was extracted with EtOAc. The extract was dried (MgSO4) and concentrated under
reduced pressure and the residue was purified by chromatography on a silica gel column with
hexane-EtOAc (3 : 1) to give quinoline (3). The remaining ionic liquid was dried at 80 °C under reduced
pressure and reused in subsequent runs.

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HETEROCYCLES, Vol. 81, No. 3, 2010
Table 1. CAN Catalyzed Friedländer Synthesis of Quinolines in [Bmim][PF6].
Entry
Yield (%)
92
2-Aminoketone 1
Ketone 2
Quinoline 3
Ph
Ph
O
O
O
O
O
1
OEt
1a
2a
3a
OEt
NH2
N
Ph
O
O
2b
2c
2d
3b
90
86
85
2
3
4
1a
N
Ph
N
O
3c
1a
1a
O
O
Ph
O
3d
N
Ph
O
5
6
84
87
2e
2f
3e
3f
1a
1a
1a
N
Ph
O
N
Ph
O
2g
3g
86
91
87
88
7
8
N
Ph
O
2h
3h
3i
1a
N
Ph
Ph
O
Cl
O
Cl
1b
9
2a
2b
OEt
O
NH2
N
Ph
N
Cl
3j
10
1b

HETEROCYCLES, Vol. 81, No. 3, 2010
693
Table 1 (Continued)
Entry 2-Aminoketone 1
Ketone 2
Quinoline 3
Yield (%)
85
Ph
O
Cl
3k
3l
11
12
13
14
2c
1b
1b
1b
1b
N
Ph
Cl
2d
2e
2f
83
85
88
N
Ph
Cl
3m
N
Ph
N
Cl
3n
Ph
N
Cl
3o
3p
87
90
15
16
1b
1b
2g
2h
Ph
Cl
N
Ethyl 2-methyl-4-phenylquinoline-3-carboxylate (3a)
1
Mp 99-100 °C (Lit.,9 99-100 °C). IR (KBr)  : 3060, 2927, 1710 cm-1. H NMR (CDCl3, 400 MHz)  :
0.91 (t, J = 7.3 Hz, 3H), 2.76 (s, 3H), 4.00-4.10 (m, 2H), 7.31-7.46 (m, 6H), 7.54 (d, J = 8.4 Hz, 1H), 7.67
13
(t, J = 8.4 Hz, 1H), 8.04 (d, J = 8.4 Hz, 1H). C NMR (CDCl3, 100 MHz)  : 13.4, 23.6, 61.1, 124.9,
126.2, 128.0, 128.3, 128.6, 129.2, 130.1, 135.5, 146.1, 147.5, 154.4, 168.2. EI-MS m/z : 291 (M+), 246,
245, 218.
1-(2-Methyl-4-phenylquinolin-3-yl)ethanone (3b)
Mp 114-115 °C (Lit.,9 111-112 °C). IR (KBr)  : 3062, 2907, 1696 cm-1. 1H NMR (CDCl3, 400 MHz)  :
1.95 (s, 3H), 2.66 (s, 3H), 7.30-7.32 (m, 2H), 7.30-7.39 (m, 1H), 7.44-7.48 (m, 3H), 7.57 (dd, J = 0.8, 8.4

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HETEROCYCLES, Vol. 81, No. 3, 2010
13
Hz, 1H), 7.63-7.68 (m, 1H), 8.03 (d, J = 8.4Hz, 1H). C NMR (CDCl3, 100 MHz)  : 23.7, 31.7, 124.8,
125.9, 126.3, 128.5, 128.6, 128.8, 129.8, 129.9, 134.6, 135.0, 143.7, 147.3, 153.3, 205.5. EI-MS m/z : 261
(M+), 246, 218, 176.
3,3-Dimethyl-9-phenyl-3,4-dihydro-2H-acridin-1-one (3c)
Mp 191 °C (Lit.,9 195 °C). IR (KBr)  : 3065, 2868, 1682 cm-1. 1H NMR (CDCl3, 400 MHz)  : 1.15 (s,
6H), 2.55 (s, 2H), 3.26 (s, 2H), 7.16-7.19 (m, 2H), 7.36-7.39 (m, 1H), 7.44-7.51 (m, 4H), 7.71-7.75 (m,
1H), 8.06 (d, J = 8.4 Hz, 1H). 13C NMR (CDCl3, 100 MHz)  : 28.2, 32.1, 48.2, 54.0, 122.5, 126.3, 127.2,
127.3, 127.9, 128.0, 128.1, 128.3, 131.5, 137.4, 148.8, 150.8, 160.9, 197.7. EI-MS m/z: 301 (M+), 300,
272, 245, 217, 189.
2,3-Dihydro-9-phenyl-1H-cyclopenta[b]quinoline (3d)
1
Mp 131-132 °C (Lit.,10 130 °C). IR (KBr)  : 3058, 2923, 1569, 1485, 831 cm-1. H NMR (CDCl3, 400
MHz)  : 2.15-2.19 (m, 2H), 2.91 (t, J = 7.2 Hz, 2H), 3.24 (t, J = 7.6 Hz, 2H), 7.35-7.41 (m, 3H),
13
7.47-7.54 (m, 3H), 7.60-7.64 (m, 2H), 8.06-8.08 (m, 1H). C NMR (CDCl3, 100 MHz)  : 23.5, 30.3,
35.1, 125.4, 125.6, 126.2, 128.2, 128.4, 129.2, 133.6, 136.7, 142.6, 147.9, 167.4. EI-MS m/z: 245 (M+),
244, 217, 168.
9-Phenyl-1,2,3,4-tetrahydroacridine(3e)
1
Mp 137 °C (Lit.,10 138 °C). IR (KBr)  : 3061, 2940, 2860, 1570, 1485, 1440, 1220, 765, 705 cm-1. H
NMR (CDCl3, 400 MHz)  : 1.75-1.81 (m, 2H), 1.93-1.99 (m, 2H), 2.59 (t, J = 6.8 Hz, 2H), 3.18 (t, J =
6.8 Hz, 2H), 7.20-7.35 (m, 4H), 7.46-7.55 (m, 3H), 7.63-7.65 (m, 1H), 8.17 (d, J = 8.4 Hz, 1H). 13C NMR
(CDCl3, 100 MHz)  : 22.4, 22.7, 27.8, 33.3, 125.8, 125.8, 126.6, 127.1, 127.9, 128.6, 128.8, 129.0, 136.5,
144.6, 147.9, 158.5. EI-MS m/z: 259 (M+), 244, 230, 217, 202, 189, 121.
11-Phenyl-7,8,9,10-tetrahydro-6H-cyclohepta[b]quinoline (3f )
Mp 109-110 °C (Lit.,11 105-107 °C). IR (KBr)  : 3054, 2927, 2851, 1571, 1485, 1443, 1196, 762, 708
cm-1. 1H NMR (CDCl3, 400 MHz)  : 1.61 (s, 2H), 1.86 (d, J = 2.4 Hz, 4H), 2.72 (t, J = 5.6 Hz, 2H), 3.38
(d, J = 3.6 Hz, 2H), 7.22-7.23 (m, 2H), 7.23-7.38 (m, 2H), 7.46-7.52 (m, 3H), 7.63 (t, J = 8.0 Hz, 1H),
8.22 (d, J = 8.4 Hz, 1H). 13C NMR (CDCl3, 100 MHz)  : 26.7, 28.1, 30.5, 31.6, 38.9, 126.0, 126.3, 126.8,
127.2, 128.4, 128.8, 129.1, 134.1, 136.9, 143.9, 146.9, 164.1. EI-MS m/z: 273 (M+), 272, 258, 244, 231,
230.

HETEROCYCLES, Vol. 81, No. 3, 2010
695
5,6-Dihydro-7-phenylbenzo[c]acridine (3g)
Mp 143-145 °C (Lit.,12 148-149 °C). IR (KBr)  : 3057, 2924, 1574, 14484, 696 cm-1. 1H NMR (CDCl3,
400 MHz)  : 2.86-2.89 (m, 4H), 7.11-7.72 (m, 11H), 8.20 (d, J = 8.4 Hz, 1H), 8.63 (dd, J = 1.2, 7.6 Hz,
13
1H). C NMR (CDCl3, 100 MHz)  : 26.4, 28.2, 125.9, 126.0, 126.3, 127.2, 127.4, 127.8, 128.0, 128.4,
128.5, 128.9, 129.5, 129.6, 130.2, 135.0, 136.9, 137.5, 139.2, 147.1, 153.0. EI-MS m/z: 307 (M+), 306,
305, 230, 152.
9-Phenyl-1,2,3,4-tetrahydro-1,4-methano-acridine (3h)
Mp 142 °C (Lit.,13 143-143.5 °C). IR (KBr)  : 3062, 2951, 2869, 1578, 758, 705 cm-1. 1H NMR (CDCl3,
400 MHz)  : 1.26-1.40 (m, 1H), 1.50-1.58 (m, 1H), 1.67 (td, J = 2.0, 12.4 Hz, 1H), 1.92-2.14 (m, 3H),
3.39 (dd, J = 1.2, 4.8 Hz, 1H), 3.59 (dd, J = 1.6, 4.0 Hz, 1H), 7.33-7.69 (m, 8H), 8.07 (d, J = 10.0 Hz, 1H).
13C NMR (CDCl3, 100 MHz)  : 25.7, 27.4, 40.8, 45.8, 46.5, 125.2, 125.7, 126.4, 127.7, 127.8, 128.3,
128.8, 129.4, 129.8, 135.9, 137.8, 138.1, 146.7, 169.9. EI-MS m/z: 272 (M++1), 271 (M+), 243, 242, 241.
Ethyl 6-chloro-2-methyl-4-phenylquinoline-3-carboxylate (3i)
Mp 102-105 °C (Lit.,10 108 °C). IR (KBr)  : 3075, 2926, 1715 cm-1. 1H NMR (CDCl3, 400 MHz)  : 0.85
(t, J = 7.2 Hz, 3H), 2.69 (s, 3H), 3.98 (q, J = 7.2 Hz, 2H), 7.25-7.45 (m, 6H), 7.51 (dd, J = 2.4, 8.8 Hz,
13
1H), 7.88 (d, J = 8.8 Hz, 1H). C NMR (CDCl3, 100 MHz)  : 13.3, 23.4, 61.1, 124.8, 125.5, 128.1,
128.3, 128.4, 129.0, 130.2, 130.7, 132.0, 134.7, 145.0, 145.7, 154.6, 167.7.
EI-MS m/z: 327 (M++2), 325 (M+), 280, 217, 216.
1-(6-Chloro-2-methyl-4-phenylquinolin-3-yl)ethanone (3j)
Mp 155-156 °C (Lit.,10 154 °C). IR (KBr)  : 3049, 2925, 1699 cm-1. 1H NMR (CDCl3, 400 MHz)  : 1.97
(s, 3H), 2.65 (s, 3H), 7.29-7.31 (m, 2H), 7.48-7.54 (m, 4H), 7.59-7.62 (m, 1H), 7.97 (d, J = 9.2 Hz, 1H).
13C NMR (CDCl3, 100 MHz)  : 23.7, 31.7, 124.8, 125.7, 128.8, 129.1, 129.8, 130.4, 130.8, 132.3, 134.3,
135.4, 142.9, 145.7, 153.8, 205.1. EI-MS m/z: 297 (M++2), 295 (M+), 280, 217, 176.
7-Chloro-3,3-dimethyl-9-phenyl-3,4-dihydro-2H-acridin-1-one (3k)
Mp 209-211 °C (Lit.,10 209-211 °C). IR (KBr)  : 3071, 2946, 1693 cm-1. 1H NMR (CDCl3, 400 MHz)  :
1.15 (s, 6H), 2.57 (s, 2H), 3.25 (s, 2H), 7.14-7.17 (m, 2H), 7.28 (d, J = 2.4 Hz, 1H), 7.42-7.55 (m, 3H),
7.69 (dd, J = 2.4, 9.0 Hz, 1H), 8.00 (d, J = 8.8 Hz, 1H). 13C NMR (CDCl3, 100 MHz)  : 28.3, 32.2, 48.2,
54.1, 123.2, 126.7, 127.8, 127.9, 128.2, 128.3, 130.1, 132.4, 132.5, 136.7, 147.3, 150.1, 161.4, 197.6.
EI-MS m/z: 337 (M++2), 335 (M+), 334, 306, 279, 216 189.

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HETEROCYCLES, Vol. 81, No. 3, 2010
7-Chloro-2,3-dihydro-9-phenyl-1H-cyclopenta[b]quinoline (3l)
1
Mp 103-104 °C (Lit.,14 105 °C). IR (KBr)  : 3038, 2923, 1601, 1483, 828 cm-1. H NMR (CDCl3, 400
MHz)  : 2.17 (m, 2H), 2.89 (t, J = 7.6 Hz, 2H), 3.22 (t, J = 7.6 Hz, 2H), 7.32-7.35 (m, 2H), 7.46-7.58 (m,
13
5H), 7.99 (d, J = 8.8 Hz, 1H). C NMR (CDCl3, 100 MHz)  : 23.4, 30.3, 35.1, 124.5, 127.0, 128.2,
128.7, 128.9, 129.1, 130.3, 131.2, 1134.6, 136.0, 141.8, 146.3, 167.8. EI-MS m/z: 281 (M++2), 279 (M+),
246, 244.
7-Chloro-9-phenyl-1,2,3,4-tetrahydroacridine (3m)
Mp 163 °C (Lit.,14 163 °C). IR (KBr)  : 3060, 2944, 1604, 1572, 1481, 1215, 703 cm-1. 1H NMR (CDCl3,
400 MHz)  : 1.78-1.82 (m, 2H), 1.94-1.98 (m, 2H), 2.61 ( t, J = 6.4 Hz, 2H), 3.29 (t, J = 6.4 Hz, 2H),
13
7.22-7.35 (m, 4H), 7.46-7.65 (m, 3H), 7.94 (d, J = 8.8 Hz, 1H). C NMR (CDCl3, 100 MHz)  : 22.8,
28.0, 34.1, 124.4, 127.3, 128.0, 128.7, 128.9, 129.1, 129.4, 130.0, 131.0, 136.3, 144.6, 145.6, 129.4.
EI-MS m/z: 295 (M++2), 293 (M+), 278, 258, 230, 189, 120, 89.
2-Chloro-11-phenyl-7,8,9,10-tetrahydro-6H-cyclohepta[b]quinoline (3n)
Mp 190-192 °C (Lit.,15 193-195 °C). IR (KBr)  : 3053, 2925, 2855, 1572, 1479, 1441, 1195, 770, 706
1
cm-1. H NMR (CDCl3, 400 MHz)  : 1.61 (s, 2H), 1.86 (s, 4H), 2.71 (t, J = 4.8 Hz, 2H), 3.36 (s, 2H),
7.21 (d, J = 6.4 Hz, 2H), 7.27 (d, J = 1.2 Hz, 1H), 7.50-7.68 (m, 4H), 8.15 (d, J = 8.8 Hz, 1H). 13C NMR
(CDCl3, 100 MHz)  : 26.6, 28.0, 30.5, 31.6, 38.8, 125.1, 127.6, 128.1, 128.6, 128.9, 129.0, 129.6, 131.9,
135.1, 136.1, 142.4, 146.1. 164.5. EI-MS m/z: 309, 307 (M+), 292, , 278, 253, 241, 216.
9-Chloro-5,6-dihydro-7-phenylbenzo[c]acridine (3o)
1
Mp 134-136 °C (Lit.,14 130 °C). IR (KBr)  : 3052, 2935, 1600, 1479, 698 cm-1. H NMR (CDCl3, 400
MHz)  : 2.81-2.90 (m, 4H), 7.24-7.59 (m, 10H), 8.11 (d, J = 8.8 Hz, 1H), 8.59 (dd, J = 1.2, 7.6 Hz,1H).
13C NMR (CDCl3, 100 MHz)  : 26.5, 28.1, 124.8, 126.3, 127.3, 127.7, 127.9, 128.2, 128.7, 129.0, 128.3,
129.4, 129.8, 131.1, 131.6, 134.7, 136.1, 139.2, 144.5, 145.5, 153.3. EI-MS m/z: 343 (M++2), 341 (M+),
304, 152.
7-Chloro-9-phenyl-1,2,3,4-tetrahydro-1,4-methanoacridine (3p)
1
Mp 144-145 °C. IR (KBr)  : 3054, 2965, 2872, 1575, 759, 701 cm-1. H NMR (CDCl3, 400 MHz)  :
1.32-1.40 (m, 1H), 1.49-1.58 (m, 1H), 1.69 (td, J = 1.2, 12.4 Hz, 1H), 1.92-2.15 (m, 3H), 3.39 (dd, J = 1.2,
5.0 Hz, 1H), 3.58 (dd, J = 1.2, 4.8 Hz, 1H), 7.34-7.58 (m, 6H), 7.63 (d, J = 3.2 Hz, 1H), 7.99 (d, J = 12.0

HETEROCYCLES, Vol. 81, No. 3, 2010
697
Hz, 1H). 13C NMR (CDCl3, 100 MHz)  : 25.7, 27.4, 40.9, 45.8, 46.4, 124.6, 127.3, 128.1, 128.5, 129.3,
129.7, 130.3, 131.0, 135.3, 137.3, 138.6, 145.2, 170.3. EI-MS m/z: 307 (M++2), 306 (M++1), 305 (M+),
277, 243, 241. Anal. Calcd for C20H16ClN (305.10): C, 78.55; H, 5.27; N, 4.58. Found: C, 78.75; H, 5.12;
N, 4.42.
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