A novel and efficient 2,4,6-trisubstituted pyridine ring synthesis via α-benzotriazolyl ketones

Article abstract of DOI:10.1055/s-1999-3637

Reaction of α-benzotriazolyl ketones with α,β-unsaturated ketones resulted in 2,4,6-triarylpyridines, 2,4-diaryl-5H-indeno[1,2-b]pyridines and 2,4-diaryl-5,6-dihydrobenzo[h]quinolines in good yields.

Full text of DOI:10.1055/s-1999-3637

2
114
PAPER
A Novel and Efficient 2,4,6-Trisubstituted Pyridine Ring Synthesis
via a-Benzotriazolyl Ketones
Alan R. Katritzky, * Ashraf A. A. Abdel-Fattah, Dmytro O. Tymoshenko, Samy A. Essawy
a
a
a
b
aCenter for Heterocyclic Compounds, Department of Chemistry, University of Florida, Gainesville, FL 32611-7200, USA
Fax +1(352)3929199; E-mail: KATRITZKY@chem.ufl.edu
bChemistry Department, Faculty of Science, Behna University, Benha, Egypt
Received 14 June 1999; revised 4 August 1999
lization of a-methoxyacetophenone (2b) results in 3b in
Abstract: Reaction of a-benzotriazolyl ketones with a,b-unsaturat-
ed ketones resulted in 2,4,6-triarylpyridines, 2,4-diaryl-5H-inde-
1
6
6
1% yield and the corresponding 4 in 60% yield.
no[1,2-b]pyridines and 2,4-diaryl-5,6-dihydrobenzo[h]quinolines Usually, Kröhnke synthesis via a,b-unsaturated ke-
in good yields.
17
18
tones and N-phenacyl-pyridinium, -quinolinium and
19
Key words: a-benzotriazolyl ketones, synthesis, 2,4,6-triarylpy- -picolinium salts (2c–e) gives 40–92% yields of a vari-
ridines, 2,4-diaryl-5H-indeno[1,2-b]pyridines, 2,4-diaryl-5,6-dihy-
drobenzo[h]quinolines
ety of polysubstituted pyridines. However, in the case of
-aryl-2-oxobut-3-enoic acids (R = COOH, R = Ar) the
1
3
4
yields were 40–77%, and 1,2,3-triphenylprop-2-en-1-one
2
(
R = Ph) afforded the corresponding tetrasubstituted py-
,4,6-Trisubstituted pyridines are important because of ridine in 25% yield. Moreover, while this reaction se-
1
7
2
1
2,3
their biological activity and optical (fluorescence and quence works well for phenacetyl derivatives, it could not
17
scintillation) properties. Their quaternary salts have syn- be extended to a-substituted ketones in general. The in-
4
,5
thetic applications. The enormous number of prepara- stability of N-phenacylpyridinium salts in strongly basic
tive approaches proposed for 2,4,6-triarylpyridines media does not allow modification of such reagents with
includes (i) [5+1] type ring annulations from a nitrogen electrophiles and limits the method to compounds with an
derivative and a five-carbon fragment, usually a 1,5-dike- ArCOCH unit as the principal building block.
2
6
tone, (ii) [2+2+2] type reactions of substituted acetylenes
7
and nitriles, (iii) [3+3] cyclizations of chalcones and im-
inophosphoranes, (iv) [4+2] reactions of unsaturated imi-
nes with enolates, (v) [2+2+1+1] Hantzsch synthesis of
polysubstituted, usually 4-aryl-3,5-alkoxycarbonylpy-
8
R3
O
X
O
Base
R2
R1
9
R4
1
0,11
ridines,
(vi) [3+2+1] approaches (see below).
2a, X = OH;
2d,
1
Methods (i) and (v) are analogous in that they require the
oxidation of dihydro intermediates. Route (ii) is based on
2b, X = CH O;
3
N
N
6
2c,
2e,
the cobalt(I) catalyzed cyclization of alkyl(aryl)alkynes
and nitriles, and can give mixtures of 4- and 5-substituted
products as well as trisubstituted benzenes as byproducts.7
Methods (iii) and (iv) require the preparation of imine
starting materials. The well-known synthesis from chal-
CH3
N
R3
R3
N
R2
X
1
2,13
CH3COONH4
R2
R1
cones via pyrylium salts
metrical 2,6-substituted pyridines, but yields are moderate
is used especially for sym-
R4
R1
R4
O
O
1
4
and limited by reversal of the aldol reaction step. Among
approaches (i–vi), type (vi) is that most frequently em-
ployed.
3
a-e
4
Scheme 1
The many [3+2+1] annulation reactions which produce
2
,4,6-trisubstituted pyridines include the base-promoted
Michael addition of a,b-unsaturated compounds 1 to ke- We previously reported 1-[a-(phosphoranylideneami-
2
0
no)alkyl]benzotriazole 5 mediated [3+3] and a-benzo-
tones or their a-substituted derivatives 2 with the forma-
tion of five-carbon intermediates 3 (Scheme 1). The
efficiency of such pyridine ring closures depends on the
nature of a-substituent X in the ketone moiety, which per-
forms as a leaving group in the aromatization process.
Thus, the standard acetic acid/ammonium acetate treat-
ment of a 4-hydroxy-substituted intermediate 3a yields a cult to attain 3-unsubstituted 2-(dialkylamino)pyridines
mixture 2,4,6-triphenylpyridine (4) and its 3-amino deriv- 10 and 2-pyridones 12. We now report the reaction of a-
ative, with the latter as the major product, while the uti- benzotriazolyl ketones with a,b-unsaturated ketones as a
triazolyl ketone 7 [3+2+1]21 pyridine ring annulations
(
Scheme 2), which lead to products 6 and 8. Our recent
study of [3+3] pyridine ring formation via a-benzotriaz-
olylacetonitrile 9 and a-benzotriazolylacylamides 11 and
22
a,b-unsaturated ketones afforded the previously diffi-
1
5
Synthesis 1999, No. 12, 2114–2118 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Novel and Efficient 2,4,6-Trisubstituted Pyridine Ring Synthesis
2115
versatile [3+2+1] synthesis of 2,4,6-trisubstituted py- approach gave us improved yields of previously synthe-
ridines (Scheme 3).
sized products 16c,d,g and provided novel pyridines
1
6e,f,h–j in high yields.
Ph
O
R2
Ph
N
R2
N
Bt
CH3COONH4
N
Base
BtH
R
Bt
Ph
N
PPh3
PPh3
R1
R3
14
-
N
-P(O)Ph3
R3
N
Ph
O
O O
R3
R1
N
R
6
R2
O
15
R
5
16a-j
N
N
1.
COOEt
N
Bt
N
Pd/C
R1
N
HN
N
17
1
O
2
. R NH2
R2
R
13
R
R
N
N
O
7
R1
R1
O
O
8
R1
N
N
N
Ph
O
N
Ph
18a,b
NHR R2
1
-
BtH
Scheme 3
R
-H O
9
2
1 2
R
N
NR R
N
10
R2
N
N
R1
R1
Bt
N
NHR R2
1
R2
O
R2
-BtH
H2O
O
R1
O
O
O
R
19
-
R
N
R2
N
NH2
1
3
1
1
12
R1
Bt
Scheme 2
R2
O
14
R1
21a-c
O
a-Benzotriazolyl ketones 14, 17, and 19 were readily syn-
thesized starting from N-chlorobenzotriazole and trimeth-
ylsilyl derivatives of corresponding ketones according to
a procedure recently elaborated in our group.2 Subse-
20
3
quent reaction with commercially available chalcones and Scheme 4
ammonium acetate in acetic acid under reflux afforded
corresponding 2,4,6-trisubstituted pyridines 16a–h in
2
-(1H-1,2,3-Benzotriazol-1-yl)indan-1-one 17 gave good
yields of the corresponding 2,4-diphenyl-5H-indeno[1,2-
b]pyridines 18a,b. 2,4-Diphenyl-5,6-dihydroben-
high yields (Table). Although in the case of unsubstituted
triphenylpyridine 16a the isolated yield was lower, our
Table 2,4,6-Triarylpyridines 16, 2,4-Diphenyl-5H-indeno[1,2-b]pyridines 18, and 2,4-Diphenyl-5,6-dihydrobenzo[h]quinolines 21
R1
R2
R3
Yield (%)
Lit. Yield (%)
1
2
2
1
7
4
5
8
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
6a
6b
6c
6d
6e
6f
6g
6h
6i
Ph
Ph
Ph
Ph
Ph
p-BrC H4
Ph
p-BrC H4
2-naphthyl
2-naphthyl
Ph
p-BrC H4
Ph
Ph
Ph
Ph
Ph
p-ClC H
p-MeC H
p-ClC H
3,4-(OCH O)C H
3,4-(OCH O)C H
p-NO C H
Ph
p-MeC H
p-MeOC H
p-BrC H
p-MeC H
p-MeOC H
p-ClC H
p-MeC H
p-MeC H
Ph
-
-
-
81
78
71
84
75
85
80
83
87
62
77
72
55
77
57
92
70
55
55
-
-
60
-
-
-
88
-
60
-
6
4
6
4
4
6
4
6
4
6 4
6
6
4
6
1
9
6
4
6
4
6
2
6
4
4
6
4
4
2
6
6
6j
2
6
4
2
1
7
7
8a
8b
1a
1b
1c
Ph
p-MeOC H
Ph
p-MeC H
p-ClC H
6
6
4
p-BrC H4
Ph
-
-
6
6
4
-
6
4
Synthesis 1999, No. 12, 2114–2118 ISSN 0039-7881 © Thieme Stuttgart · New York

2
116
A. R. Katritzky et al.
PAPER
zo[h]quinolines 21a–c were synthesized using two syn-
C
23
H
17
N
1
calcd
N
4.56
4.56
thetic approaches (Scheme 4). Both of them, i.e. starting (307.14)
found
from a-benzotriazolylacetophenones 14 and 2-(1H-1,2,3-
2
-(4-Methylphenyl)-4,6-diphenylpyridine (16b)
benzotriazol-1-yl)-3,4-dihydronaphthalen-1(2H)-one 19,
24
Needles; yield: 0.75 g (78%); mp 133–135 °C (Lit. mp 124–
led to desired products 21a–c in good yields (Table). 125 °C).
Thus, the extension of a-phenacetyl mediated
1
H NMR: d = 8.22 (d, 2H, J = 7.1 Hz), 8.13 (d, 2H, J = 8.0 Hz), 7.89
s, 2H), 7.75 (d, 2H, J = 6.9 Hz), 7.55–7.43 (m, 6H), 7.33 (d, 2H,
1
7
methodology to a-substituted ketones in general was
(
achieved. We believe that the reaction mechanism in- J = 8.0 Hz), 2.44 (s, 3H).
volves initial formation of intermediate 2-benzotriazolyl
,5-diketone 15, further reaction with ammonia and elim-
13
C NMR: d = 157.4, 150.1, 139.7, 139.0, 129.4, 129.1, 129.0,
28.9, 128.7, 127.2, 127.1, 127.0, 117.1, 116.8, 21.3.
1
1
ination of the benzotriazole moiety to result in the desired
annulation product. Thus, in a separate experiment under
mild conditions (THF, –78 °C, BuLi) in the absence of an
ammonia precursor, the intermediate 2-(benzotriazol-1-
yl)-1,3,5-triphenylpentane-1,5-dione (15, R = R = R =
Ph) was isolated in 74% yield.
C H N
calcd
C
89.68
89.91
H
5.96
6.12
N
4.36
4.46
2
4
19
(321.41)
found
2
-(4-Methoxyphenyl)-4,6-diphenylpyridine (16c)
2
5
1
2
3
Needles; yield: 0.72 g (71%); mp 99–101 °C (Lit. mp 105–
1
07 °C).
1
H NMR: d = 8.21 (d, 2H, J = 7.4 Hz), 8.19 (d, 2H, J = 8.8 Hz), 7.84
s, 2H), 7.75 (d, 2H, J = 7.1 Hz), 7.55–7.45 (m, 6H), 7.05 (d, 2H,
(
J = 8.7 Hz), 3.89 (s, 3H).
Mps were measured with a Kofler hot stage apparatus without cor-
rection. The H NMR and C NMR spectra were recorded on a
1
13
13
C NMR: d = 160.5, 157.3, 157.1, 150.1, 139.7, 139.2, 132.2,
Varian Gemini (300 MHz) spectrometer in CDCl with TMS as the
3
129.0, 128.9, 128.6, 128.4, 127.1, 116.4, 116.3, 114.0, 55.3.
internal standard. Elemental analyses were performed using a Carlo
Erba 1106 elemental analyzer.
C H NO calcd
C
85.43
85.16
H
5.68
5.76
N
4.15
4.20
2
4
19
(337.15)
found
1
2
=
-(Benzotriazol-1-yl)-1,3,5-triphenylpentane-1,5-dione (15, R
R = R = Ph)
2
-(4-Bromophenyl)-4,6-diphenylpyridine (16d)
2
3
18
Needles; yield: 0.97 g (84%); mp 150–152 °C (Lit. mp 152–
153 °C).
Under a N atmosphere, 1.6 M BuLi in hexane (1.63 mL, 2.6 mmol)
2
was added to a solution of 2-benzotriazol-1-ylacetophenone (0.47 g,
1
H NMR: d = 8.19 (d, 2H, J = 7.1 Hz), 8.08 (d, 2H, J = 8.5 Hz), 7.89
s, 1H), 7.84 (s, 1H), 7.73 (d, 2H, J = 6.8 Hz), 7.64 (d, 2H, J = 8.5
2
mmol) in dry THF at –78 °C. Benzalacetophenone (0.41 g, 2
(
mmol) was added dropwise and the mixture was stirred for 12 h
while the temperature was allowed to rise to r.t. The mixture was
quenched with water (50 mL) and extracted with CH Cl (2 ¥ 30
Hz), 7.56–7.46 (m, 6H).
1
3
2
2
C NMR: d = 157.6, 156.2, 150.3, 139.4, 138.8, 138.4, 131.8,
129.1, 129.0, 128.7, 127.1, 123.5, 117.4, 116.8.
mL). The combined organics were dried (MgSO ). The solvent was
4
removed under reduced pressure to give crude product, which was
recrystallized from MeOH to give 15 as microcrystals; yield: 0.66 g
C H BrN calcd
C
71.50
71.34
H
4.17
4.23
N
3.63
3.63
2
3
16
(386.29)
found
(74%); mp 177–179 °C.
1
4-(4-Chlorophenyl)-2-(4-methylphenyl)-6-phenylpyridine (16e)
Needles; yield: 0.80 g (75%); mp 120–122 °C.
H NMR: d = 8.13 (d, 2H, J = 7.6 Hz), 7.93 (d, 1H, J = 7.5 Hz),
.86 (d, 2H, J = 8.5 Hz), 7.59–7.00 (m, 15H), 4.92–4.85 (m, 1H),
.62 (d, 2H, J = 6.5 Hz).
7
3
1
H NMR: d = 8.18 (d, 2H, J = 7.1 Hz), 8.08 (d, 2H, J = 8.2 Hz), 7.79
1
3
(s, 1H), 7.78 (s, 1H), 7.64 (d, 2H, J = 8.5 Hz), 7.53–7.42 (m, 5H),
C NMR: d = 197.5, 192.6, 146.0, 138.2, 136.7, 135.0, 134.2,
33.2, 132.2, 128.9, 128.8, 128.7, 128.6, 128.5, 128.3, 128.2, 128.0,
27.8, 127.5, 127.3, 123.8, 119.8, 111.0, 66.4, 41.7, 41.2.
7
.31 (d, 2H, J = 8.0 Hz), 2.43 (s, 3H).
1
1
13
C NMR: d = 157.6, 148.8, 139.5, 139.2, 137.6, 136.6, 135.1,
1
1
29.5, 129.3, 129.2, 129.1, 128.7, 128.5, 128.4, 127.1, 127.0, 116.8,
16.4, 21.3.
C H N O calcd
N
9.43
9.42
2
9
23
3
2
(
445.52)
found
C H ClN calcd
C
81.10
81.10
H
5.11
5.24
N
3.94
3.99
2
4
18
Synthesis of 2,4,6-Triarylpyridines 16, 2,4-Diaryl-5H-indeno
1,2-b]pyridines 18, and 2,4-Diaryl-5,6-dihydrobenzo[h]quino-
(355.11)
found
[
2
-(4-Bromophenyl)-6-(4-methoxyphenyl)-4-(4-methylphe-
lines 21; General Procedure
nyl)pyridine (16f)
Plates; yield: 1.1 g (85%); mp 167–169 °C.
A solution of corresponding a-(benzotriazol-1-yl) ketone 14, 17, or
1
9 (3 mmol), corresponding chalcone (3 mmol) and ammonium ac-
1
H NMR: d = 8.13 (d, 2H, J = 8.3 Hz), 8.06 (d, 2H, J = 8.2 Hz), 7.81
(s, 1H), 7.76 (s, 1H), 7.62 (d, 4H, J = 8.0 Hz), 7.32 (d, 2H, J = 7.7
Hz), 7.03 (d, 2H, J = 8.3 Hz), 3.88 (s, 3H), 2.44 (s, 3H).
etate (3 g) in glacial HOAc (4 mL) was refluxed for 30 h. After ad-
dition of ice water (50 mL), the precipitate was separated and
purified by column chromatography (silica gel, CHCl /hexanes 2:1)
or by recrystallization from hexanes to give products 16a–j, 18a,b
and 21a–c.
3
13
C NMR: d = 160.6, 157.1, 156.0, 150.0, 139.1, 138.6, 136.0,
32.0, 131.7, 129.8, 128.6, 128.3, 126.9, 123.3, 116.3, 115.9, 114.0,
1
2
,4,6-Triphenylpyridine (16a)
55.4, 21.3.
1
7
Needles; yield: 0.75 g (81%); mp 129–131 °C (Lit. mp 137–
1
C H BrNO calcd
C
69.77
69.58
H
4.68
4.47
N
3.25
3.26
2
5
20
38 °C).
(430.35)
found
1
H NMR: d = 8.25 (d, 4H, J = 8.5 Hz), 7.92 (s, 2H), 7.89–7.76 (m,
H), 7.58–7.45 (m, 9H).
2
,4-Bis(4-chlorophenyl)-6-phenylpyridine (16g)
2
1
9
Plates; yield: 0.90 g (80%); mp 140–142 °C (Lit. mp 136–
37 °C).
1
3
C NMR: d = 157.5, 150.2, 139.6, 139.1, 129.1, 129.0, 128.7,
27.1, 117.1.
1
1
Synthesis 1999, No. 12, 2114–2118 ISSN 0039-7881 © Thieme Stuttgart · New York

PAPER
A Novel and Efficient 2,4,6-Trisubstituted Pyridine Ring Synthesis
2117
1
H NMR: d = 8.13 (dd, 4H, J = 7.9, 8.5 Hz), 7.80 (s, 1H), 7.74 (s,
H), 7.62 (d, 2H, J = 8.2 Hz), 7.52–7.44 (m, 7H).
C H BrNO calcd
C
70.10
70.05
H
4.24
4.16
N
3.27
3.24
2
5
18
1
1
(428.33)
found
3
C NMR: d = 157.7, 156.3, 149.0, 139.1, 137.7, 137.2, 135.3,
2
,4-Diphenyl-5,6-dihydrobenzo[h]quinoline (21a)
1
35.3, 129.3, 129.2, 128.9, 128.8, 128.4, 128.3, 127.1, 117.0, 116.4.
Prisms; yield: 0.55 g (55%); mp 121–123 °C.
C H Cl N calcd
C
73.35
72.94
H
3.97
3.88
N
3.72
3.69
1
2
3
15
2
H NMR: d = 8.58 (d, 1H, J = 7.7 Hz), 8.18 (d, 2H, J = 8.1 Hz), 7.59
(s, 1H), 7.51–7.39 (m, 8H), 7.33 (t, 1H, J = 7.4 Hz), 7.23 (s, 1H),
(
376.29)
found
7
.21(t, 1H, J = 7.4 Hz), 2.96–2.92 (m, 2H), 2.88–2.82 (m, 2H).
4
-(1,3-Benzodioxol-5-yl)-2-(4-bromophenyl)-6-(4-methylphe-
1
3
nyl)pyridine (16h)
C NMR: d = 154.4, 152.6, 149.2, 139.6, 139.4, 138.2 135.2,
Plates ; yield: 1.1 g (83%); mp 160–162 °C (Lit.26 mp 178–181 °C).
129.0, 128.8, 128.7, 128.6, 128.5, 128.0, 127.9, 127.6, 127.1, 126.8,
125.7, 119.9, 28.2, 25.3.
1
H NMR: d = 8.06–8.02 (dd, 4H, J = 2.8, 3.2 Hz), 7.75 (s, 1H), 7.69
(
(
1
s, 1H), 7.60 (d, 2H, J = 8.2 Hz), 7.30 (d, 2H, J = 8.0 Hz), 7.20–7.16
C H N
calcd
N
4.20
4.14
2
5
19
m, 2H), 6.92 (d, 1H), 6.02 (s, 2H), 2.42 (s, 3H).
3
(333.44)
found
C NMR: d = 157.5, 156.0, 149.7, 148.5, 139.1, 138.5, 136.5,
33.0, 131.7, 129.4, 129.3, 128.6, 126.9, 123.4, 121.0, 116.6, 116.0,
08.8, 107.4, 101.5, 21.3.
2
-(4-Bromophenyl)-4-(4-methylphenyl)-5,6-dihydrobenzo-
1
1
[
h]quinoline (21b)
Prisms; yield: 0.98 g (77%); mp 170–172 °C.
C H BrNO calcd
C
67.58
67.66
H
4.08
4.01
N
3.15
3.14
1
2
5
18
2
H NMR: d = 8.54 (d, 1H, J = 7.3 Hz), 8.05 (d, 2H, J = 8.4 Hz), 7.59
(
444.33)
found
(d, 2H, J = 8.2 Hz), 7.54 (s, 1H), 7.43–7.21 (m, 7H), 2.93–2.91 (m,
2
H), 2.86–2.84 (m, 2H), 2.44 (s, 3H).
4
-(1,3-Benzodioxol-5-yl)-2-(2-naphthyl)-6-(4-methylphenyl)py-
1
3
ridine (16i)
Plates; yield: 1.08 g (87%); mp 161–163 °C.
C NMR: d = 153.1, 152.6, 149.4, 138.5, 138.2, 138.0, 136.1,
135.0, 131.7, 129.2, 128.7, 128.6, 128.3, 127.5, 127.0, 125.6, 123.0,
119.6, 28.1, 25.3, 21.3.
1
H NMR: d = 8.62 (s, 1H), 8.34 (d, 1H, J = 8.6 Hz), 8.11 (d, 2H,
J = 8.0 Hz), 7.99–7.94 (m, 2H), 7.90–7.86 (m, 2H), 7.78 (s, 1H),
C H N
calcd
N
3.29
3.25
2
5
19
7
.50 (t, 2H, J = 4.6 Hz), 7.32 (d, 2H, J = 8.0 Hz), 7.23 (s, 1H), 7.23
(426.36)
found
(s, 1H), 6.94 (d, 1H, J = 7.8 Hz), 6.02 (s, 2H), 2.43 (s, 3H).
4
-(4-Chlorophenyl)-2-phenyl-5,6-dihydrobenzo[h]quinoline
1
3
C NMR: d = 157.6, 157.2, 149.6, 148.5, 148.4, 139.0, 137.0,
36.8, 133.7, 133.5, 133.2, 129.4, 128.7, 128.3, 127.7, 127.0, 126.4,
26.2, 124.9, 121.1, 116.7, 116.5, 108.8, 107.5, 101.5, 21.3.
(
21c)
1
1
Prisms; yield: 0.63 g (57%); mp 130–131 °C.
1
H NMR: d = 8.57 (d, 1H, J = 7.5 Hz), 8.16 (d, 2H, J = 7.4 Hz), 7.53
s, 1H), 7.50–7.38 (m, 7H), 7.33 (s, 1H), 7.32 (d, 1H, J = 8.3 Hz),
C H NO calcd
C
83.83
83.56
H
5.09
5.11
N
3.37
3.35
2
9
21
2
(
(
415.50)
found
7.22 (s, 1H), 7.21 (d, 1H, J = 7.8 Hz), 2.90–2.79 (m, 4H).
1
3
2
-(2-Naphthyl)-4-(4-nitrophenyl)-6-phenylpyridine (16j)
C NMR: d = 154.4, 152.6, 149.2, 139.6, 139.3, 138.2, 135.2,
Plates; yield: 0.75 g (62%); mp 183–184 °C.
129.0, 128.8, 128.7, 128.6, 128.5, 128.0, 127.9, 127.5, 127.1, 126.8,
125.7, 119.9, 28.2, 25.3.
1
H NMR: d = 8.66 (s, 1H), 8.38 (t, 3H, J = 8.8 Hz), 8.24 (d, 2H,
J = 7.1 Hz), 8.01 (s, 2H), 7.99 (d, 1H, J = 9.9 Hz), 7.94–7.89 (m,
C H ClN calcd
C
81.62
81.49
H
4.93
4.96
N
3.81
3.75
2
5
18
4
H), 7.59–7.47 (m, 5H), 7.26 (s, 1H).
found
1
3
C NMR: d = 156.9, 156.7, 147.9, 147.4, 144.2, 138.6, 135.9,
33.5, 133.1, 129.5, 128.9, 128.9, 128.7, 128.3, 127.7, 127.1, 126.9,
26.6, 126.5, 124.7, 124.1, 117.3, 117.1.
1
1
References
C H N O calcd
N
6.96
6.97
(1) Shirai, H.; Hanabusa, K.; Takahashi, Yu.; Mizobe, F.;
Hanada, K. Jap. Pat. 93126541 (1993); Chem. Abstr. 1995,
22, 178410j.
2
7
18
2
2
(
402.46)
found
1
2
,4-Diphenyl-5H-indeno[1,2-b]pyridine (18a)
(
2) Knyazhanskii, M. I.; Makarova, N. I.; Olekhnovich, E. P.;
2
7
Microcrystals; yield: 0.74 g (77%); mp 157–159 °C (Lit. mp
Pichko, V. A.; Kharlanov, V. A. Zh. Org. Khim. 1996, 32,
1
56 °C).
1097.
1
H NMR: d = 8.29 (d, 1H, J = 7.4 Hz), 8.21 (d, 2H, J = 7.2 Hz),
.90–7.42 (m, 12H), 4.01 (s, 2H).
(3) Kurfurst, A.; Lhotak, P.; Petru, M.; Kuthan, J. Collect. Czech.
Chem. Commun. 1989, 54, 462.
7
(
(
4) Katritzky A. R. Tetrahedron 1980, 36, 679.
5) Katritzky, A. R.; Marson, C. M. Angew. Chem., Int. Ed. Engl.
1
3
C NMR: d = 161.1, 157.1, 146.3, 144.1, 141.2, 139.9, 138.9,
1
32.8, 128.8, 128.7, 128.5, 128.2, 127.1, 124.9, 121.4, 118.1, 34.4.
1984, 23, 420.
C H N
calcd
C
90.24
90.46
H
5.37
5.37
N
4.39
4.45
(6) Jones, G. In Comprehensive Heterocyclic Chemistry;
2
4
17
Katritzky, A. R.; Rees, C. W., Eds.; Pergamon: New York,
(
319.40)
found
1
984; Vol. 2, Part 2A, p 395.
7) Bönnemann, H.; Brinkmann, R.; Schenkluhn, H. Synthesis
974, 57.
8) Kobayashi, T.; Nitta, M. Chem. Lett. 1986, 1549.
2
-(4-Bromophenyl)-4-(4-methoxyphenyl)-5H-indeno[1,2-b]py-
(
(
ridine (18b)
Prisms; yield: 0.93 g (72%); mp 134–136 °C.
1
1
H NMR: d = 8.20 (d, 1H, J = 7.3 Hz), 8.02 (d, 2H, J = 7.0 Hz),
(9) Kiselyov, A. S. Tetrahedron Lett. 1995, 36, 9297.
(10) Sausinš, A.; Duburs, G. Heterocycles 1988, 27, 269.
(11) Sausinš, A.; Duburs, G. Heterocycles 1988, 27, 291.
7
3
.61–7.37 (m, 8H), 7.03 (d, 2H, J = 6.9 Hz), 3.92 (s, 2H), 3.88 (s,
H).
(
12) Dorofeenko, G. N.; Olekhnovich, E. P.; Laukhina, L. I. Zh.
Org. Khim. 1971, 7, 1296.
1
3
C NMR: d = 161.1, 159.9, 155.6, 145.9, 144.0, 141.0, 138.7,
32.9, 131.7, 130.8, 129.4, 128.7, 128.6, 127.1, 124.9, 123.0, 121.2,
17.4, 114.2, 55.4, 34.5.
1
1
(13) Bak, T.; Rasala, D.; Gawinecki, R. Org. Prep. Proced. Int.
1994, 26, 101.
Synthesis 1999, No. 12, 2114–2118 ISSN 0039-7881 © Thieme Stuttgart · New York

2
118
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37, 4577.
(
(
(
14) Barrio, M. C. G.; Barrio, J. R.; Walker, G.; Novelli, A.;
Leonard, N. J. J. Am. Chem. Soc. 1973, 95, 4891.
15) Moskovkina, T. V.; Vysotskii, V. I.; Tilichenko, M. N. Khim.
Geterotsikl. Soedin. 1986, 1321.
16) Teuber, H. J.; Bader, H. J.; Schuetz, G. Liebigs Ann. Chem.
(25) Tewari, R. S.; Dubey, A. K. Indian J. Chem. Sect. B 1980, 19,
153.
1
977, 1335.
(
(
(
17) Kröhnke, F. Synthesis 1976, 1.
(26) Kendurkar, S; Tewari, R. S. Z. Naturforsch., B: Anorg. Chem.
Org. Chem. 1974, 29, 552.
(27) Katritzky, A. R.; El-Mowafy, A. M.; Musumarra, G.;
Sakizadeh, K.; Sana-Ullah, C. J. Org. Chem. 1981, 46, 3823.
18) Tewari, R. S.; Dubey, A. K. J. Chem. Eng. Data 1980, 25, 91.
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Chem. Eng. Data 1980, 26, 106.
(
(
(
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M. F. J. Org. Chem. 1994, 59, 2740.
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Synthesis 1999, No. 12, 2114–2118 ISSN 0039-7881 © Thieme Stuttgart · New York