International Journal of Organic Chemistry, 2011, 1, 218-223
doi:10.4236/ijoc.2011.14032 Published Online December 2011 (http://www.SciRP.org/journal/ijoc)
Heterosynthesis Using Nitriles: Novel
Pyrrolo[2,3-b]pyridines
Fathy M. Abdelrazek1*, Ahmed A. Fadda2, Samar S. Mohamed1
1Chemistry Department, Faculty of Science, Cairo University, Giza, Egypt
2Chemistry Department, Faculty of Science, Mansoura University, Mansoura, Egypt
Received August 2, 2011; revised September 13, 2011; accepted September 21, 2011
Abstract
2-Amino-4-benzoyl-1-arylpyrrole-3-carbonitriles react with arylidene malonodinitriles, β-ketoesters and β-
diketones to afford pyrrolo[2,3-b]pyridine derivatives.
Keywords: N-Arylpyrroles, Cinnamonitriles, Pyrrolo[2,3-b]py r i dine s
1. Introduction
Pyrroles and their fused derivatives represent an impor-
tant class of heterocyclic compounds due to their diverse
biological and pharmaceutical activities [1-4].
In the last two decades we were involved in a program
aiming to develop new simple routes for the synthesis of
heterocyclic compounds of anticipated biological activity
to be evaluated as biodegradable agrochemicals [5-8].
We have reported the synthesis of a variety of pyrrole,
N-substituted pyrrole and fused-pyrrole derivatives of
biological interest [9-16]. Recently some pyrrolo[2,3-b]
pyridine derivatives were shown to be effective as inhi-
bitors of tumor necrosis factor alpha [17]. This encour-
aged us to prepare some new N-substituted pyrrolo-py-
ridine derivatives for biological evaluation study. The
pyrrole derivatives 2a-d (Scheme 1; obtained recently by
us) [18] seemed suitable precursors to fulfill this object-
tive through exploring the presence of the enaminonitrile
moiety [19] as a site of reaction.
2. Results and Discussion
Pyrrole derivatives 2a-d (Scheme 1; available from ena-
minone 1 in reaction with aromatic amines) [18] were
reacted with the (hetero) arylidenes of malonodinitrile
3a-c to afford yellow to brown colored products.
Based on their elemental analyses as well as mass and
spectral data structures 6a-l were assigned to these prod-
ucts. These new compounds are assumed to be formed
via nucleophilic addition of the -NH2 of 2a-d to the acti-
vated double bond in 3 to produce firstly the intermedi-
ates 4a-l which subsequently undergo cyclization via the
active methyne protons to yield intermediates 5a-l, whi-
ch in role loses HCN to afford the isolable products 6a-l
(Scheme 1).
Next, compounds 2a-d were treated with β-ketoesters
7a and 7b to yield pyrrolo-[2,3-b]-pyridine derivatives 9a-
h via, most likely, the intermediates 8a-h which were
formed by trans amidation followed by an intramolecular
addition of the active methylene to the cyano group. Ele-
mental analyses and spectral data were in complete agre-
ement with the proposed structures 9a-h.
Compounds 2a-d also react with β-diketones 10a and
10b to give highly colored products. It is assumed that
this third type of cyclocondensation reaction occurred via
the intermediates 11a-h which then undergo addition of
the active methylene to the CN group to yield the pyrrolo
[2,3-b]pyridine derivatives 12a-h. Elemental analyses
and spectral data were fully consistent with the proposed
structures 12a-h.
3. Experimental
Melting points were measured on an Electrothermal (9100)
apparatus and are uncorrected. IR spectra were recorded
as KBr pellets on a Perkin Elmer 1430 spectrophotome-
ter. The 1H NMR and 13C NMR spectra were carried out
on a Varian Gemini 300 MHz spectrometer in DMSO-d6
using TMS as internal standard and chemical shifts are
expressed in δ ppm values. Assignments were made by
correlation of the off-resonance decoupled 13C-NMR
spectra and determination of the 1H-chemical shifts. Ma-
ss spectra were recorded on a Shimadzu GCMS-GB
1000 PX (70 ev). Elemental analyses were carried out at
the Micro-analytical Center at Cairo University.

219 F. M. ABDELRAZEK ET AL.
NN
H
O
CN
Ph
Ar
CN
CN
Ar
1
N
O
Ph
Ar
HN
N
H
CN
CN
Ar1
NNH
2
O
CN
Ph
Ar
CN
CN
Ar
1
N
O
Ph
Ar
H
2
N
N
CN
Ar
1
6a-l
2
EtOH/Et
3
N
Reflux
45
2; Ar=
a, Ph;
b, 4-MeC
6
H
4
;
c, 4-MeOC
6
H
4
;
d, 4-ClC
6
H
4
6; Ar= Ar
1
=
a,Ph Ph
b,4-MeC
6
H
4
;Ph
c,4-MeOC
6
H
4
;Ph
d, 4-ClC
6
H
4
Ph
-HCN
Ar
1
=a, Ph
b,C
4
H
3
O
c,C
4
H
3
S
e, Ph; C
4
H
3
O
f, 4-MeC
6
H
4
;C
4
H
3
O
g, 4-MeOC
6
H
4
;C
4
H
3
O
h, 4-ClC
6
H
4
C
4
H
3
O
i,Ph; C
4
H
3
S
j, 4-MeC
6
H
4
;C
4
H
3
S
k, 4-MeOC
6
H
4
;C
4
H
3
S
l , 4-ClC
6
H
4
C
4
H
3
S
NN
H
CN
Ph
Ar
O
COR
R
OO
OEt
7a,b
8
O
N
Ph
Ar
H
2
N
NO
COR
9a-h
O
a,R=Me
b,R=Ph
NN
H
O
CN
Ph
Ar
COR
R
R
OO
R
N
O
Ph
Ar
H
2
N
NR
COR
11
10a,b
12a-h
a, R=Me
b, R=Ph
9,12; Ar=R,
a, Ph Me
b, 4-MeC
6
H
4
Me
c, 4-MeOC
6
H
4
Me
d, 4-ClC
6
H
4
Me
O
CN
CN
Ph
N
1
ArNH
2
Dioxan/Pip.
Reflux
Dioxan/NaOEt
Reflux
EtOH/
Reflux 3
H
Ar= R=
e, Ph Ph
f, 4-MeC
6
H
4
Ph
g, 4-MeOC
6
H
4
Ph
h, 4-ClC
6
H
4
Ph
Scheme 1. The derivation of pyrr ole.
Preparation of pyrr ol o[ 2,3-b]pyridines 6a-l:
To a solution of each of the pyrrole derivatives 2a-d
(0.01 mol) in ethanol (20 mL) 0.01 mol of each of (het-
ero) benzylidenemonitriles 3a, 3b or 3c was added fol-
lowed by few drops of triethylamine as catalyst. The re-
action mixture was refluxed for 2 h and then left to cool
overnight. The precipitated solids were collected by fil-
tration and recrystallized from ethanol/DMF to give the
title compounds 6a-l.
4-Amino-3-benzoyl-1,6-diphenyl-1H-pyrrolo[2,3-b]
pyridine-5-carbonitrile 6a: Yellow crystalline solid;
yield 75% (3.1 g); mp 212˚C - 213˚C. max = 3350, 3230
(NH2), 2210 (CN), 1653 (CO) cm–1; MS: m/z = 414 (M+).
δH = 5.56 (s, 2H D2O exch., NH2), 6.85 (s, 1H, pyrrole
2-H), 7.25 - 8.05 (m, 15H, Ar-H); δC = 87.7 (s), 104.4 (s),
106.3 (s), 120.3 (d), 125.4 (d), 127.2 (d), 127.2 (d), 117.3
(s), 127.3 (d), 128.7 (d), 129.0 (d), 129.4 (d), 129.6 (d),
132.9 (d), 133.3 (s), 139.7 (s), 140.5 (s), 154.5 (s), 155.3
(s), 158.7 (s), 187.5 (s). Anal. Calcd for C27H18N4O
(414.46): C, 78.24; H, 4.38; N, 13.52. Found: C, 78.30;
H, 4.41; N, 13.42.
4-Amino-3-benzoyl-6-phenyl-1-p-tolyl-1H-pyrrolo[2,
3-b]pyridine-5-carbonitrile 6b: Yellow crystalline solid;
yield 68% (2.91 g); mp 224˚C - 225˚C. max = 3352,
3235 (NH2), 2212 (CN), 1655 (CO) cm–1; δH = 2.32 (s,
3H, CH3), 5.55 (s, 2H D2O exch., NH2), 6.83 (s, 1H,
pyrrole 2-H), 7.26 - 8.00 (m, 14H, Ar-H). Anal. Calcd for
C28H20N4O (428.48): C, 78.49; H, 4.70; N, 13.08. Found:
C, 78.55; H, 4.52; N, 13.22.
4-Amino-3-benzoyl-1-(4-methoxyphenyl)-6-phenyl-1H-
pyrrolo[2,3-b]pyridine-5-carbonitrile 6c: Yellow cry-
stalline solid; yield 68% (3.0 g); mp 229˚C - 230˚C. max
= 3355, 3238 (NH2), 2215 (CN), 1668 (CO) cm–1; MS:
m/z = 444 (M+). δH = 3.76 (s, 3H, CH3), 5.57 (s, 2H D2O
exch., NH2), 6.84 - 8.02 (m, 15H, Ar-H). Anal. Calcd for
C28H20N4O2 (444.48): C, 75.66; H, 4.54; N, 12.60. Found:
C, 75.70; H, 4.58; N, 12.48.

F. M. ABDELRAZEK ET AL.
220
4-Amino-3-benzoyl-1-(4-chlorophenyl)-6-phenyl-1
H-pyrrolo[2,3-b]pyridine-5-carbonitrile 6d: Yellowish
green crystalline solid; yield 78% (3.5 g); mp 235˚C -
237˚C. max = 3353, 3235 (NH2), 2213 (CN), 1663 (CO)
cm–1; δH = 5.54 (s, 2H D2O exch., NH2), 6.88 (s, 1H,
pyrrole 2-H), 7.25 - 8.05 (m, 14H, Ar-H). Anal. Calcd for
C27H17ClN4O (448.90): C, 72.24; H, 3.82; N, 12.48.
Found: C, 72.30; H, 3.85; N, 12.55.
4-Amino-3-benzoyl-6-(furan-2-yl)-1-phenyl-1H-pyr
rolo[2,3-b]pyridine-5-carbonitrile 6e: Yellowish brown
powder; yield 65% (2.63 g); mp 169˚C - 170˚C. max =
3328, 3230 (NH2), 2213 (CN), 1658 (CO) cm–1; MS: m/z
= 404 (M+). δH = 5.57 (s, 2H D2O exch., NH2), 6.35 -
7.85 (m, 14H, Ar-H). Anal. Calcd for C25H16N4O2
(404.42): C, 74.25; H, 3.99; N, 13.85. Found: C, 74.32;
H, 3.95; N, 13.65.
4-Amino-3-benzoyl-6-(furan-2-yl)-1-p-tolyl-1H-pyr
rolo[2,3-b]pyridine-5-carbonitrile 6f: Brownish pow-
der; yield 63% (2.63 g); mp 173˚C - 175˚C. max = 3330,
3232 (NH2), 2213 (CN), 1660 (CO) cm–1; δH = 2.33 (s,
3H, CH3), 5.62 (s, 2H D2O exch., NH2), 6.32 - 7.82 (m,
13H, Ar-H). Anal. Calcd for C26H18- N4O2 (418.45): C,
74.63; H, 4.34; N, 13.34. Found: C, 74.52; H, 4.45; N,
13.55.
4-Amino-3-benzoyl-1-(4-methoxyphenyl)-6-(furan-2-
yl)-1H-pyrrolo[2,3-b]pyridine-5-carbonitrile 6g: Brown
powder; yield 67% (2.91 g); mp 178˚C - 179˚C. max =
3335, 3228 (NH2), 2211 (CN), 1663 (CO) cm–1; MS: m/z
= 434 (M+). δH = 3.83 (s, 3H, CH3), 5.63 (s, 2H D2O
exch., NH2), 6.35 - 7.85 (m, 13H, Ar-H). Anal. Calcd for
C26H18N4O3 (434.45): C, 71.88; H, 4.18; N, 12.90. Found:
C, 71.92; H, 4.25; N, 13.05.
4-Amino-3-benzoyl-1-(4-chlorophenyl)-6-(furan-2-y
l)-1H-pyrrolo[2,3-b]pyridine-5-carbonitrile 6h: Green-
ish brown powder; yield 69% (3.0 g); mp 192˚C - 193˚C.
max = 3342, 3235 (NH2), 2217 (CN), 1668 (CO) cm–1;
δH = 5.65 (s, 2H D2O exch., NH2), 6.37 - 7.88 (m, 13H,
Ar-H). Anal. Calcd for C25H15ClN4O2 (438.87): C 68.42;
H 3.45; Cl 8.08; N 12.77. Found: C 68.45; H 3.52; Cl
8.18; N 12.85.
4-Amino-3-benzoyl-1-phenyl-6-(thiophen-2-yl)-1H-p
yrrolo[2,3-b]pyridine-5-carbonitrile 6i: Yellowish crys-
talline solid; yield 72% (3.0 g); mp 174˚C - 175˚C. max
= 3329, 3232 (NH2), 2218 (CN), 1654 (CO) cm–1; δH =
5.55 (s, 2H D2O exch., NH2), 6.95 - 7.84 (m, 14H, Ar-H).
Anal. Calcd for C25H16N4OS (420.49): C, 71.41; H, 3.84;
N, 13.32. Found: C 71.48; H 3.92; N 13.45.
4-Amino-3-benzoyl-6-(thiophen-2-yl)-1-p-tolyl-1H-p
yrrolo[2,3-b]pyridine-5-carbonitrile 6j: Brownish fine
crystals; yield 68% (2.95 g); mp 181˚C - 182˚C.max =
3333, 3235 (NH2), 2220 (CN), 1667 (CO) cm–1; MS: m/z
= 434 (M+). δH = 2.34 (s, 3H, CH3), 5.63 (s, 2H D2O
exch., NH2), 6.92 - 7.82 (m, 13H, Ar-H). Anal. Calcd for
C26H18N4OS (434.51): C, 71.87; H, 4.18; N, 12.89; S,
7.38. Found: C, 71.95; H, 4.25; N, 12.62; S, 7.52.
4-Amino-3-benzoyl-1-(4-methoxyphenyl)-6-(thiophen
-2-yl)-1H-pyrrolo[2,3-b]pyridine-5-carbonitrile 6k: Br-
own fine crystals; yield 66% (2.97 g); mp 205˚C - 206˚C.
max = 3340, 3238 (NH2), 2215 (CN), 1670 (CO) cm–1;
MS: m/z = 450 (M+). δH = 3.78 (s, 3H, CH3), 5.62 (s, 2H
D2O exch., NH2), 6.85 - 7.84 (m, 13H, Ar-H). Anal.
Calcd for C26H18N4O2S (450.51): C, 69.32; H, 4.03; N,
12.44; S, 7.12. Found: C, 69.38; H, 4.13; N, 12.55; S,
7.25.
4-Amino-3-benzoyl-1-(4-chlorophenyl)-6-(thiophen
-2-yl)-1H-pyrrolo[2,3-b]pyridine-5-carbonitrile 6l: Pale
greenish brown powder; yield 73% (3.3 g); mp 209˚C -
210˚C. max = 3344, 3238 (NH2), 2221 (CN), 1672 (CO)
cm–1; δH = 5.66 (s, 2H D2O exch., NH2), 6.95 - 7.79 (m,
13H, Ar-H). Anal. Calcd for C25H15ClN4OS (454.93): C,
66.00; H, 3.32; Cl, 7.79; N, 12.32; S, 7.05. Found: C,
66.10; H, 3.38; Cl, 8.00; N, 12.45; S, 7.23.
Preparation of pyrr ol o[ 2,3-b]pyridines 9a-h:
To a solution of each of the pyrrole derivatives 2a-d
(0.01 mol) in dioxane (20 mL) 0.01 mol of β-ketoesters
7a or 7b was added followed by few drops of piperidine
catalyst. The reaction mixture was refluxed for 2 h then
left to cool overnight. The precipitated solids were col-
lected by filtration and recrystallized from dioxane to
afford the title compounds 9a-h.
5-Acetyl-4-amino-3-benzoyl-1-phenyl-1,7-dihydro-
pyrrolo[2,3-b]pyridine-6-one 9a: Yellow crystals; yield
75% (2.78 g); mp 207˚C - 208˚C. max = 3420 - 2235 (br.
NH & NH2), 1645, 1653 & 1678 (3CO) cm–1; MS: m/z =
371 (M+). δH = 2.35 (s, 3H, CH3), 5.56 (s, 2H D2O exch.,
NH2), 6.93 (s, 1H, pyrrole 2-H), 7.28 - 7.85 (m, 10H,
Ar-H), 8.22 (s, 1H, NH); δC = 22.4 (q), 111.2 (s), 112.3
(s), 112.4 (s), 119.9 (s), 120.2 (d), 120.6 (s), 125.4 (d),
128.6 (d), 129.2 (d), 129.5 (d), 132.4 (d), 133.3 (s), 140.5
(s), 163.7 (s), 167.4 (s), 186.7 (s), 196.5 (s). Anal. Calcd
for C22H17N3O3 (371.39): C, 71.15; H, 4.61; N, 11.31.
Found: C, 71.20; H, 4.68; N, 11.50.
5-Acetyl-4-amino-3-benzoyl-1-(p-t olyl)-1,7-dihydro-
pyrrolo[2,3-b]pyridine-6-one 9b: Yellow crystals; yield
73% (2.8 g); mp 210˚C - 212˚C. max = 3425 - 2232 (br.
NH & NH2), 1646, 1650 & 1673 (3CO) cm–1; MS: m/z =
385 (M+). δH = 2.33 (s, 3H, CH3), 2.36 (s, 3H, CH3), 5.55
(s, 2H D2O exch., NH2), 6.91 (s, 1H, pyrrole 2-H), 7.15 -
7.84 (m, 9H, Ar-H), 8.14 (s, 1H, NH); Anal. Calcd for
C23H19N3O3 (385.42): C 71.67; H 4.97; N 10.90. Found:
C 71.62; H 5.05; N 10.58.
5-Acetyl-4-amino-3-benzoyl-1-(4-methoxyphenyl)-1,
7-dihydropyrrolo[2,3-b]pyridine-6-one 9c: Yellow cry-
stals; yield 74% (2.96 g); mp 199˚C - 201˚C. max = 3428
- 2233 (br. NH & NH2), 1644, 1652 & 1674 (3CO) cm–1;
δH = 2.32 (s, 3H, CH3), 3.80 (s, 3H, CH3), 5.57 (s, 2H

221 F. M. ABDELRAZEK ET AL.
D2O exch., NH2), 6.84 - 7.82 (m, 10H, Ar-H), 8.58 (s,
1H, NH); Anal. Calcd for C23H19N3O4 (401.41): C, 68.82;
H 4.77; N 10.47. Found: C 68.60; H 5.00; N 10.65.
5-Acetyl-4-amino-3-benzoyl-1-(4-chlorophenyl)-1,7-
dihydropyrrolo[2,3-b]pyridine-6-one 9d: Greenish yel-
low crystalline solid; yield 77% (3.12 g); mp 215˚C -
216˚C. max = 3430 - 2235 (br. NH & NH2), 1640, 1654
& 1673 (3CO) cm–1; δH = 2.34 (s, 3H, CH3), 5.58 (s, 2H
D2O exch., NH2), 6.95 (s, 1H, pyrrole 2-H), 7.18 - 7.80
(m, 9H, Ar-H), 8.65 (s, 1H, NH); Anal. Calcd for
C22H16ClN3O3 (405.83): C 65.11; H 3.97; Cl 8.74; N
10.35. Found: C 65.20; H 4.07; Cl 8.65; N 10.25.
4-Amino-3,5-dibenzoyl-1-phenyl-1,7-dihydropyrrol
o[2,3-b]pyridine-6-one 9e: Dark yellow crystals; yield
75% (3.25 g); mp 237˚C - 238˚C. max = 3460 - 3235 (br.
NH & NH2), 1642, 1653 & 1655 (3CO) cm–1; MS: m/z =
433 (M+). δH = 6.95 (s, 1H, pyrrole 2-H), 7.25 - 7.84 (m,
15H, Ar-H), 8.15 (s, 2H D2O exch., NH2), 10.4 (s, 1H
D2O exch., NH); Anal. Calcd for C27H19N3O3 (433.46: C,
74.81; H, 4.42; N, 9.69. Found: C, 74.70; H, 4.45; N,
9.55.
4-Amino-3,5-dibenzoyl-1-(p-tolyl)-1,7-dihydropyr-
rolo[2,3-b]pyridine-6-one 9f: Brownish yellow powder;
yield 65% (2.90 g); mp 220˚C - 222˚C. max = 3455 -
3228 (br. NH & NH2), 1647, 1655 & 1658 (3CO) cm–1;
MS: m/z = 447 (M+). δH = 2.36 (s, 3H, CH3), 6.94 (s, 1H,
pyrrole 2-H), 7.12 - 7.84 (m, 14H, Ar-H), 8.18 (s, 2H
D2O exch., NH2), 10.6 (s, 1H D2O exch., NH); Anal.
Calcd for C28H21N3O3 (447.48): C, 75.15; H, 4.73; N,
9.39. Found: C, 74.90; H, 4.50; N, 9.52.
4-Amino-3,5-dibenz oyl-1-(4-methoxyphenyl )-1,7-di-
hydropyrrolo[2,3-b]pyridine-6-one 9g: Brownish yel-
low powder; yield 64% (2.96 g); mp 210˚C - 212˚C. max
= 3455 - 3228 (br. NH & NH2), 1644, 1655 & 1658
(3CO) cm–1; δH = 2.36 (s, 3H, CH3), 6.94 (s, 1H, pyrrole
2-H), 7.12 - 7.84 (m, 14H, Ar-H), 8.18 (s, 2H D2O exch.,
NH2), 10.6 (s, 1H D2O exch., NH); Ana l. Calcd for
C28H21N3O4 (463.48): C, 72.56; H, 4.57; N, 9.07. Found:
C, 72.72; H, 4.52; N, 9.22.
4-Amino-3,5-dibenzoyl-1-(4-chlorophenyl)-1,7-dihyd-
ropyrrolo[2,3-b]pyridine-6-one 9h: Greenish yellow
powder; yield 66% (3.1 g); mp 227˚C - 229˚C. max =
3455 - 3228 (br. NH & NH2), 1646, 1654 & 1660 (3CO)
cm–1; δH = 2.34 (s, 3H, CH3), 6.94 (s, 1H, pyrrole 2-H),
7.16 - 7.83 (m, 14H, Ar-H), 8.18 (s, 2H D2O exch., NH2),
10.65 (s, 1H D2O exch., NH); Anal. Calcd for C27H18-
ClN3O3 (467.90): C 69.31; H 3.88; Cl 7.58; N 8.98.
Found: C 69.35; H 3.95; Cl 7.74; N 9.08.
Synthesis of pyrrolo[2,3-b]pyridines 12a-h:
To a solution of each of the pyrrole derivatives 2a-d
(0.01 mol) in dioxane (20 mL) 0.01 mol of each of
β-diketones 10a or 10b was added followed by a cata-
lytic amount of sodium ethoxide. The reaction mixture
was refluxed for 3 h and then left to cool to room tem-
perature. The reaction mixture was then poured on ice
cold water and neutralized with few drops of conc. HCl
(pH 7). The precipitated solids were collected by filtra-
tion and recrystallized from ethanol/DMF to afford the
title compounds 12a-h.
5-Acetyl-4-amino-3-benzoyl-6-methyl-1-pheny l-1H-
pyrrolo[2,3-b]pyridine 12a: Yellow flakes; yield 72%
(2.66 g); mp 230˚C - 231˚C. max = 3355 & 3228 (NH2),
1655 & 1662 (2CO) cm–1; MS: m/z = 369 (M+). δH =
2.44 (s, 3H, CH3), 2.50 (s, 3H, CH3), 6.92 (s, 1H, pyrrole
2-H), 7.25 - 7.85 (m, 10H, Ar-H), 8.22 (s, 2H D2O exch.,
NH2); δC = 14.3(q), 22.6 (q), 102.7(s), 107.2 (s), 111.2(s),
120.3(d), 125.3(d), 128.3(d), 128.7(d), 129.2(d), 129.6(d),
132.5(d), 133.4(s), 140.5(s), 147.2(s), 148.7(s), 153.8(s),
185.3(s), 195.5(s). Anal. Calcd for C23H19N3O2 (369.42):
C, 74.78; H, 5.18; N, 11.37. Found: C, 74.85; H, 5.22; N,
11.50.
5-Acetyl-4-amino-3-benzoyl-6-methyl-1-(p-tolyl)-1
H-pyrrolo[2,3-b]pyridine 12b: Dark yellow powder;
yield 68% (2.6 g); mp 237˚C - 239˚C. max = 3358 &
3232 (NH2), 1656 & 1665 (2CO) cm–1; δH = 2.37 (s, 3H,
CH3), 2.46 (s, 3H, CH3), 2.52 (s, 3H, CH3), 6.88 (s, 1H,
pyrrole 2-H), 7.05 - 7.82 (m, 9H, Ar-H), 8.25 (s, 2H D2O
exch., NH2); Anal. Calcd for C24H21N3O2 (383.44): C,
75.18; H, 5.52; N, 10.96. Found: C, 75.35; H, 5.28; N,
10.75.
5-Acetyl-4-amino-3-benzoyl-1-(4-methoxyphenyl) -6
-methyl-1H-pyrrolo[2,3-b]pyridine 12c: Brownish ye-
llow powder; yield 66% (2.63 g); mp 245˚C - 246˚C.
max = 3354 & 3222 (NH2), 1653 & 1660 (2CO) cm–1;
MS: m/z = 399 (M+). δH = 2.45 (s, 3H, CH3), 2.50 (s, 3H,
CH3), 3.77 (s, 3H, CH3), 6.79 - 7.84 (m, 10H, Ar-H),
8.35 (s, 2H D2O exch., NH2); Anal. Calcd for C24H21-
N3O3 (399.44): C, 72.16; H, 5.30; N, 10.52. Found: C,
72.32; H, 5.25; N, 10.70.
5-Acetyl-4-amino-3-benzoyl-1-(4-chlorophenyl)-6-
methyl-1H-pyrrolo[2,3-b]pyridine 12d: Lemon yellow
powder; yield 70% (2.82 g); mp 257˚C - 259˚C. max =
3355 & 3226 (NH2), 1648 & 1656 (2CO) cm–1; δH = 2.48
(s, 3H, CH3), 2.52 (s, 3H, CH3), 6.93 (s, 1H, pyrrole 2-H),
7.15 - 7.84 (m, 9H, Ar-H), 8.24 (s, 2H D2O exch., NH2);
Anal. Calcd for C23H18ClN3O2 (403.86): C, 68.40; H, 4.49;
Cl, 8.78; N, 10.40. Found: C, 68.48; H, 4.55; Cl, 8.85; N,
10.50.
4-Amino-3,5-dibenzoy l-1,6-diphenyl-1H-pyrrolo[2,
3-b]pyridine 12e: Reddish yellow powder; yield 76%
(3.75 g); mp 272˚C - 273˚C. max = 3345 & 3186 (NH2),
1642 & 1650 (2CO) cm–1; MS: m/z = 493 (M+). δH =
6.92 (s, 1H, pyrrole 2-H), 7.18 - 7.85 (m, 20H, Ar-H),
8.44 (s, 2H D2O exch., NH2); Anal. Calcd for C33H23N3O2
(493.55): C, 80.31; H, 4.70; N, 8.51. Found: C, 80.35; H,
4.78; N, 8.65.

F. M. ABDELRAZEK ET AL.
222
4-Amino-3,5-dibenzoyl-6-phenyl-1-p-tolyl-1H-pyrr-
olo[2,3-b]pyridine 12f: Red powder; yield 72% (3.65 g);
mp 279˚C - 280˚C. max = 3346 & 3192 (NH2), 1640 &
1652 (2CO) cm–1; δH = 2.30 (s, 3H, CH3), 6.95 (s, 1H,
pyrrole 2-H), 7.15 - 7.82 (m, 19H, Ar-H), 8.39 (s, 2H
D2O exch., NH2); Anal. Cal- cd for C34H25N3O2 (507.58):
C, 80.45; H, 4.96; N, 8.28. Found: C, 80.36; H, 4.80; N,
8.60.
4-Amino-3,5-dibenzoyl-1-(4-methoxyphenyl)-6-phen
yl-1H-pyrrolo[2,3-b]pyridine 12g: Red powder; yield
72% (3.76 g); mp 290˚C - 292˚C. max = 3348 & 3222
(NH2), 1641 & 1655 (2CO) cm–1; δH = 3.80 (s, 3H, CH3),
6.78 - 7.83 (m, 20H, Ar-H), 8.22 (s, 2H D2O exch., NH2);
Anal. Calcd for C34H25N3O3 (523.58): C, 77.99; H, 4.81;
N, 8.03. Found: C, 80.76; H, 4.80; N, 8.20.
4-Amino-3,5-dibenzoyl-1-(4-chlorophenyl)-6-pheny
l-1H-pyrrolo[2,3-b]pyridine 12h: Crimson red powder;
yield 73% (3.85 g); mp 305˚C - 307˚C. max = 3354 &
3229 (NH2), 1652 & 1658 (2CO) cm–1; δH = 6.91 (s, 1H,
pyrrole 2-H), 7.18 - 7.83 (m, 19H, Ar-H), 8.36 (s, 2H
D2O exch., NH2); Anal. Calcd for C33H22ClN3O2 (528.00):
C, 75.07; H, 4.20; Cl, 6.71; N, 7.96. Found: C, 75.00; H,
4.25; Cl, 6.78; N, 7.75.
4. Conclusions
A rapid and concise synthesis of three new series of
highly functionalized pyrrolo[2,3-b]pyridines was de-
scribed as occurring with satisfactory to good yields.
They were offset by the simplicity of our strategy to-
gether with the structural profits gained. The envisaged
biological activity of compounds is in progress.
5. Acknowledgements
The continuous help and support of the Alexander von
Humboldt-Foundation (Germany) to F. M. Abdelrazek
through granting short research fellowships is greatly
acknowledged. The kind hospitality of Professor Peter
Metz, Institut für Organische Chemie, TU Dresden is
also highly appreciated.
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