The Gould-Jacob type of reaction for the synthesis of novel pyrimidopyrrolopyrimidines: A comparison of classical heating vs solvent free microwave irradiation

Article abstract of DOI:10.1002/jhet.5570430530

The Gould-Jacob type of reaction for the synthesis of ethyl 4-oxo-8,10-substituted-4,8-dihydropyrimido[1,2-c]pyrrolo[3,2-e] pyrimidine-3-carboxylates 5 has been carried out conventionally by the condensation between 4-aminopyrrolo[2,3-d]pyrimidines 2 and

Full text of DOI:10.1002/jhet.5570430530

Sep-Oct 2006
1343
The Gould-Jacob Type of Reaction for the Synthesis of Novel
Pyrimidopyrrolopyrimidines : A Comparison of Classical heating vs
Solvent Free Microwave Irradiation
Nirmal D. Desai*
Loyola Centre for Research & Development, St. Xavier’s College, Navrangpura, Ahmedabad-380009, India.
nirmaldesai_3@yahoo.com
Received October 8, 2005
Dedicated to the Memory of Dr. Chaitanya G. Dave
COOC2H5
COOC2H5
NH2
HN
N
R
R
C2H5OOC
COOC2H5
OC2H5
DPO
N
N
+
130-40 O
C
N
N
H
N
R1
R1
2a-m
3
4a-m
DPO
250 O
C
COOC2H5
O
N
N
N
R
C2H5OOC
COOC2H5
OC2H5
MW
2a-m
+
Neat, 10-12 min
N
H
R1
5a-m
3
The Gould-Jacob type of reaction for the synthesis of ethyl 4-oxo-8,10-substituted-4,8-dihydropyrimido[1,2-
c]pyrrolo[3,2-e]pyrimidine-3-carboxylates 5 has been carried out conventionally by the condensation between 4-
aminopyrrolo[2,3-d]pyrimidines 2 and diethyl ethoxymethylenemalonate 3 via acyclic intermediates diethyl N-
[5,7-substituted-7H-pyrrolo[2,3-d]pyrimidin-4-yl]aminomethylenemalonates 4 and the results obtained were
compared with single step microwave irradiation under solvent free conditions for the synthesis of 5.
J. Heterocyclic Chem., 43, 1343 (2006).
Introduction.
especially appealing for providing an environmentally benign
system. So far no attention has been given towards the
synthesis of angular triheterocyclic pyrimidopyrrolopyrimidine
using EMME as a synthon. Therefore in continuation of our
interest [19] in fused triheterocyclic systems, we report herein
Gould-Jacob type of reaction for the synthesis of novel
pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidines 5 using conven-
tional as well as microwave methodologies and comparative
study of both the methods have been carried out.
Cyclocondensation of 2-amino-4,5-substituted-1H-pyrrole-
3-carbonitriles [20-22] 1 with formamide afforded the
building blocks 4-amino-5,7-substituted-7H-pyrrolo[2,3-
d]pyrimidine [21,22] 2 required for the synthesis of
pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidines 5 (Scheme-1).
Diethyl ethoxymethylenemalonate (EMME) has been
employed frequently in Gould-Jacob reaction for the synthesis
of quinoline derivatives [1]. Many heterocyclic systems such
as 1,8-naphthyridines, 2H-pyrido[1,2-a]pyrimidin-4-ones,
pyrazolinones, pyrons, xanthyrones, guanidine derivatives,
1,2,4-triazoles, 3-oxo-1,2,6-thiadiazines, 8-oxoimidazo[1,2-
a]pyrimidines, 3H-pyrrolo[1,2-a]indol-3-one derivatives and
1H-1,4-benzodiazepines have been obtained using EMME as
synthon [2]. EMME is widely used in push-pull alkane [3],
1,4-addition elimination [4], 1,4 addition [5], [3+2] cyclo-
additions [6], Diels-Alder reactions [8] and extensively
reviewed as Michael reagent [7]. Dave et al [9,10] reported a
novel route for the synthesis of pyrido[3,2-e]pyrimido[1,2-
c]pyrimidines and thieno[3,2-e]pyrimido[1,2-c]pyrimidines
using the same synthon. Microwave accelerated organic
synthesis is an effective and an alternative route proposed
during the last decade due to drastic reduction in the reaction
time, to minimize cumbersome work-up and better yields [11-
14]. Organic synthesis under solvent free conditions is of great
relevance because of emerging environmental issues [15]. The
solvent-free reactions [16-18] under microwave conditions are
Scheme 1
NH2
R
CN
R
HCONH2
DMF
N
N
NH2
N
N
R1
R1
1a-m
2a-m

1344
N. D. Desai
Vol 43
In two step conventional method 4-aminopyrrolo[2,3-
which on thermal cyclization in boiling diphenyl oxide at 250
°C for 2-3 hours provided ethyl 4-oxo-8,10-substituted-
4,8-dihydropyrimido[1,2-c]pyrrolo[3,2-e]pyrimidine-3-
carboxylates 5 in 50-65 % overall yields from 4-
d]pyrimidines 2 were condensed with EMME 3 at 130-140
°C for 3.5-4.5 hours to obtain diethyl N-[5,7-substituted-7H-
pyrrolo[2,3-d]pyrimidin-4-yl]aminomethylenemalonates 4,
Scheme 2
COOC2H5
COOC2H5
NH2
HN
N
R
R
C2H5OOC
COOC2H5
OC2H5
DPO
N
N
+
130-40 O
C
N
R1
N
H
N
R1
2a-m
3
4a-m
DPO
250 O
C
COOC2H5
O
N
N
N
R
C2H5OOC
COOC2H5
OC2H5
MW
2a-m
+
Neat, 10-12 min
N
H
R1
5a-m
3
Compound 4 ,5 (a-m)
R
R1
a
b
c
d
e
f
C6H5
C6H5
C6H5
C6H5
C6H5
C6H5
4-OCH3C6H4
4-FC6H4
4-ClC6H4
3-Cl-4-FC6H3
C6H5
4-OCH3C6H4
g
h
i
4-OCH3C6H4
4-OCH3C6H4
4-OCH3C6H4
4-Cl C6H4
4-OCH3C6H4
4-FC6H4
3-Cl-4-FC6H3
C6H5
j
k
l
m
4-Cl C6H4
4-Cl C6H4
4-Cl C6H4
4-FC6H4
4-ClC6H4
3-Cl-4-FC6H3
Table 1
A comparison between conventional and microwave assisted synthesis of pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidines 5.
Compound
No.
Conventional
(Method A)
Time[c]
Hours
Yield[d]
%
Microwave[e]
Yield[d]
%
Melting point
°C
(Method B)
Time[c]
Minutes
10
5a
5b
5c
5d
5e
5f
5g
5h
5i
5
5.5
6
5
5.5
6
5.5
5
5
6
5
60
63
65
57
62
64
57
55
60
61
65
54
62
68
64
69
66
69
75
65
74
68
72
76
70
65
168-70
183-85
198-200
240-42
225-27
202-04
186-88
193-95
245-47
248-50
213-15
220-22
240-42
12
11
12
11.5
12
10.5
11
10
12
10.5
10
5j
5k
5l
5.5
5
5m
12
[c] = overall time on the basis of two steps, [d] = overall yields on the basis of starting compound 2; [e] = microwave
irradiation was carried out in a domestic microwave oven (BPL, BMO 700T).

Sep-Oct 2006 The Gould-Jacob Type of Reaction for the Synthesis of Novel Pyrimidopyrrolopyrimidines
1345
aminopyrrolo[2,3-d]pyrimidines 2 (Method A). On the other
hand, single step microwave assisted reaction of 2 with
EMME 3 without solvent (Method B) provided identical
compound 5 within 10-12 min in 65-75 % overall yields
(Scheme 2). Thus microwave assisted synthesis of
pyrimidopyrrolopyrimidines 5 has remarkable advantages
over the conventional techniques because of easier workup,
better yields, rapid and solvent free cleaner reactions. The
comparison between conventional and microwave
methodologies has been shown in Table 1.
were responsible for two ethyl groups present in
malonates 4. The absence of a band due to NH group in
the area 3256-3250 cm-1 in IR (KBr) spectra supported the
formation of angular
pyrimidopyrrolopyrimidines 5.
Absorption at 1744-1724 cm-1 appeared due to an ester
carbonyl group whereas absorption due to lactone was
found to be shifted 20-30 cm-1 higher wave number as
compared to ketones of acyclic malonates producing a
sharp band in the region 1704-1692 cm-1. The presence of
triplet at ꢀ 1.36-1.51 (3H) and quartet at ꢀ 4.36-4.46
1
IR (KBr) spectra of 4 exhibited a characteristic band for
NH in the region 3280-3260 cm-1 along with two sharp
absorption around 1720-1668 cm-1 due to carbonyl groups
of two ester functionalities and the C=C and C=N
vibrations were found at 1608-1500 cm-1. The absence of
amino vibrations in the region 3500-3400 cm-1 and the
presence of absorption near 3256-3250 cm-1 due to NH
(2H) in the H NMR (DMSO-d6) spectra of 5 indicated
a single ethyl group, where as pyrimidine protons at C2
and C6 were appeared as singlet at ꢀ 8.81-9.11 and
9.75-9.81 each integrating for one proton. While pyrrole
ring proton at C9 was merged in aromatic region ꢀ 6.98-
7.71. The mass spectrum of ethyl 8-(3-chloro-4-
fluorophenyl)-10-(4-methoxyphenyl)-4-oxo-4,8-dihydro-
pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidine-3-carboxylate
5i exhibited a characteristic molecular ion peak at m/e
492. The fragment ion (M–COOC2H5) was obtained at
m/e = 419.
1
suggested the formation of acyclic intermediate 4. H
NMR (CDCl3) of 4 exhibited a doublet at ꢀ 10.78-11.28
integrating for 1H because of the NH proton, a doublet for
vinyl proton in the area ꢀ 9.29-9.67 and singlet at ꢀ 8.60-
8.78 due to pyrimidine ring proton were found to be
present. Twin triplet and quartet in the region ꢀ 1.23-1.42
and ꢀ 4.08-4.31 integrating for 3H and 2H respectively
In conclusion, we have developed a simple, fast,
solvent-free and high yielding method for the synthesis of
novel pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidines.
Table 2
Physical and Analytical Data of Compounds 4a-4m
Compound
No.
Reaction
time
(hours)
Yield
%
mp °C
Crystallization
Solvent
Molecular
Formula/
Molecular
weight
Analysis %
Calcd / Found
H
C
N
4a
4b
4c
4d
4e
4f
3
3.5
4
63
68
60
65
73
52
70
61
67
69
68
70
75
120-22
[a]
153-55
[a]
128-30
[a]
171-73
[a]
158-60
[a]
138-40
[a]
155-57
[a]
143-45
[a]
165-67
[a]
135-37
[a]
163-65
[a]
202-04
[a]
C26H24N4O4
456.49
C27H26N4O5
486.52
C26H23FN4O4
474.48
C26H23ClN4O4
490.94
C26H22ClFN4O4
508.93
C27H26N4O5
486.52
C28H28N4O6
516.55
C27H25FN4O5
504.51
C27H24ClFN4O5
538.95
C26H23ClN4O4
490.94
C26H22ClFN4O4
508.93
C26H22Cl2N4O4
525.38
68.41
68.20
66.65
66.41
65.81
65.44
63.61
63.38
61.36
61.30
66.65
66.53
65.11
65.43
64.28
64.41
60.17
59.96
63.61
63.45
61.36
61.64
59.44
59.10
57.47
57.22
5.30
5.12
5.39
5.25
4.89
5.02
4.72
4.36
4.36
4.32
5.39
5.11
5.46
5.11
4.99
4.62
4.49
4.72
4.72
4.48
4.36
4.61
4.22
4.47
3.90
3.62
12.27
12.49
11.52
11.22
11.81
11.77
11.41
11.32
11.01
10.91
11.52
11.61
10.85
10.61
11.11
10.93
10.40
10.69
11.41
11.36
11.01
11.30
10.66
10.39
10.31
10.09
4.5
5
5
4g
4h
4i
4
4
3.5
3
4j
4k
4l
4
3
4m
4
210-12
[a]
C26H21Cl2FN4O4
543.37
[a] = chloroform+.

1346
N. D. Desai
Vol 43
Table 2 (continued)
Physical and Analytical Data of Compounds 5a-5m
Compound
No.
Reaction
time
(hours)
Yield
%
mp °C
Crystallization
Solvent
Molecular
Formula/
Molecular
weight
Analysis %
Calcd / Found
H
C
N
5a
5b
5c
5d
5e
5f
5
5.5
6
60
63
65
57
62
64
57
55
60
61
65
54
62
168-70
[b]
183-85
[b]
198-200
[b]
240-42
[b]
225-27
[b]
202-04
[b]
186-88
[b]
193-95
[b]
245-47
[b]
248-50
[b]
213-15
[b]
220-22
[b]
C24H18N4O3
410.42
C25H20N4O4
440.45
C24H17FN4O3
428.42
C24H17ClN4O3
444.87
C24H16ClFN4O3
462.86
C25H20N4O4
440.45
C26H22N4O5
470.48
C25H19FN4O4
458.44
C25H18ClFN4O4
492.89
C24H17ClN4O3
444.87
C24H16ClFN4O3
462.68
C24H16Cl2N4O3
479.31
70.23
70.42
68.17
68.44
67.28
67.53
64.80
64.88
62.28
62.04
68.17
68.39
66.37
66.62
65.50
65.41
60.92
60.75
64.80
64.63
62.28
62.48
60.14
60.31
57.96
59.63
4.42
4.12
4.58
4.69
4.00
3.73
3.85
4.08
3.48
3.39
4.58
4.22
4.71
4.44
4.18
4.33
3.68
3.89
3.85
3.62
3.48
3.65
3.36
3.11
3.04
3.39
13.65
13.89
12.72
12.49
13.08
12.88
12.59
12.31
12.10
11.88
12.72
12.64
11.91
12.10
12.22
12.49
11.37
11.02
12.59
12.71
12.10
11.98
11.69
11.48
11.27
10.97
5
5.5
6
5g
5h
5i
5.5
5
5
5j
6
5k
5l
5
5.5
5
5m
240-42
[b]
C24H15Cl2FN4O3
497.31
[b] = N,N-dimethylformamide:ethanol (6:4 v\v).
EXPERIMENTAL
Step 2: Synthesis of Ethyl 4-oxo-8,10-substituted-4,8-dihydro-
pyrimido[1,2-c]pyrrolo[3,2-e]pyrimidine-3-carboxylates 5a-5m.
Melting points were determined by electro thermal method in
open capillary tube and are uncorrected. The IR spectra were
recorded in cm-1 for KBr pellets on Buck scientific spectro-
Diethyl N-[5,7-substituted-7H-pyrrolo[2,3-d]pyrimidin-4-yl]-
aminomethylenemalonate 4 (1.0 g) was dissolved in boiling
diphenyl oxide (5 ml) and heated at 250 °C for 1.5-2.0 hours.
The excess of solvent distilled in vacuo and methanol (15 ml)
was added to the cooled reaction mixture, the solid obtained was
collected by filtration and crystallized (Table 2).
1
photometer. The H NMR spectra were recorded on Varian 400
MHz spectrophotometer in deuteriodimethyl sulfoxide or deuterio-
chloroform using TMS as internal standard and the chemical shifts
are expressed in ppm. MS spectra were recorded on LKB 9000 mass
spectrophotometer. Microwave irradiation was carried out in
domestic BPL microwave oven, Model BMO 700T (2450 MHz, 700
W). The purity of the compounds was routinely checked by TLC
using silica gel G and spots were exposed in iodine vapour.
Microwave Assisted Method B.
Single Step Synthesis of Ethyl 4-oxo-8,10-substituted-4,8-
dihydropyrimido[1,2-c]pyrrolo[3,2-e]pyrimidine-3-carboxylates
5a-5m.
General Procedure for the synthesis of Ethyl 4-oxo-8,10-
substituted-4,8-dihydropyrimido[1,2-c]pyrrolo[3,2-e]pyrimidine-3-
carboxylates 5a-5m.
A neat mixture of 4-amino-5,7-substituted-7H-pyrrolo[2,3-d]-
pyrimidine 2 (0.01 mole) and diethyl ethoxymethylenemalo-
nate 3 (2.16 g 0.01 mole) was taken in an open Pyrex tube and
subjected to microwave irradiation in a domestic microwave
oven (BPL, BMO 700T) at an output of about 700 watts for
specified time mentioned in (Table 1). Progress of reaction was
monitored through TLC at an interval of 45 seconds. On
completion, the reaction mixture was allowed to cool at room
temperature and the solid obtained was crystallized from N,N-
dimethylformamide:ethanol (6:4 v/v). The products thus
obtained were identical with products formed by method A
which were confirmed on the basis of TLC, mp, elemental and
spectral analysis. The yields and melting points are given in
(Table 1).
Two Step Conventional Method A.
Step 1: Synthesis of Diethyl N-[5,7-substituted-7H-pyrrolo[2,3-d]-
pyrimidin-4-yl]aminomethylenemalonates 4a-4m.
A mixture of 4-amino-5,7-substituted-7H-pyrrolo[2,3-d]pyrimidine
[21,22] 2 (0.01 mol ), EMME 3 (2.16 g 0.01 mol) and diphenyl oxide
(5 ml) was heated at 130-140 °C for 3.5 to 4.0 hours, and the alcohol
generated from the reaction mixture was allowed to escape. The
reaction mixture was then cooled and diluted with n-hexane (25 ml).
The precipitates thus formed were filtered, washed with cold
methanol, dried and crystallized (Table 2).

Sep-Oct 2006 The Gould-Jacob Type of Reaction for the Synthesis of Novel Pyrimidopyrrolopyrimidines
1347
Table 3
IR and 1H NMR Spectral Data for Compounds 4a-4m
Compound
No.
4a
IR (KBr) cm-1
1H NMR (CDCl3 / TMS) (ꢀ ppm)
3270,1696,1668,1600,1510
1.25-1.36 (two t, 6H, OCH2CH3, J = 7.12 Hz), 4.09-4.29 (two q, 4H, OCH2CH3, J = 7.14 Hz),
7.26-7.87(m, 11H, Ar-H), 8.65 (s, 1H, H at C2), 9.31-9.34 (d, 1H, =CH, J = 12.24 Hz), 10.80-
10.83 (d, 1H, NH, J = 12.2 Hz)
4b
4c
4d
4e
4f
3270,1712,1672,1624,1520
3280,1724,1678,1612,1512
3270,1716,1668,1616,1512
3270,1708,1668,1612,1508
3280,1712,1672,1612,1504
3270,1714,1672,1612,1504
3280,1716,1668,1616,1516
3260,1700,1670,1618,1524
3270,1716,1664,1600,1506
3260,1718,1668,1610,1512
3270,1712,1664,1612,1516
3260,1720,1686, 1600,1524
1.26-1.37 (two t, 6H, OCH2CH3, J = 7.12 Hz), 3.89 (s, 3H, OCH3), 4.11-4.31 (two q, 4H,
OCH2CH3, J = 7.12 Hz), 7.22-7.91 (m, 10H, Ar-H), 8.72 (s, 1H, H at C2), 9.32-9.35 (d, 1H, =CH,
J = 12.16 Hz), 10.81-10.84 (d, 1H, NH, J = 12 Hz)
1.24-1.35 (two t, 6H, OCH2CH3, J = 7.08 Hz), 4.12-4.32 (two q, 4H, OCH2CH3, J = 7.12 Hz),
7.26-7.99 (m, 10H, Ar-H), 8.68 (s, 1H, H at C2), 9.33-9.36 (d, 1H, =CH, J = 12.12 Hz), 10.83-
10.86 (d, 1H, NH, J = 12 Hz)
1.26-1.37 (two t, 6H, OCH2CH3, J = 7.12 Hz), 4.10-4.30 (two q, 4H, OCH2CH3, J = 7.16 Hz),
7.20-7.88 (m, 10H, Ar-H), 8.69 (s, 1H, H at C2), 9.32-9.35 (d, 1H, =CH, J = 12.16 Hz), 10.82-
10.85 (d, 1H, NH, J = 12.08 Hz)
1.23-1.34 (two t, 6H, OCH2CH3, J = 7.08 Hz), 4.09-4.29 (two q, 4H, OCH2CH3, J = 7.12 Hz),
7.21-7.90 (m, 9H, Ar-H), 8.71(s, 1H, H at C2), 9.31-9.34 (d, 1H, =CH, J = 12.12 Hz), 10.81-
10.84 (d, 1H, NH, J = 12 Hz)
1.26-1.37 (two t, 6H, OCH2CH3, J = 7.0 Hz), 3.89 (s, 3H, OCH3), 4.10-4.30 (two q, 4H,
OCH2CH3, J = 7.12 Hz), 7.21-7.93 (m, 10H, Ar-H), 8.71 (s, 1H, H at C2), 9.31-9.34 (d,1H, =CH,
J = 12.24 Hz), 10.82-10.85 (d, 1H, NH, J = 12.16 Hz)
1.23-1.34 (two t, 6H, OCH2CH3, J = 7.12 Hz), 3.91 (s, 6H, OCH3), 4.09-4.29 (two q, 4H,
OCH2CH3, J = 7.16 Hz), 7.23-7.89 (m, 9H, Ar-H), 8.68 (s, 1H, H at C2), 9.32-9.35 (d, 1H, =CH,
J = 12.24 Hz), 10.81-10.84 (d, 1H, NH, J = 12.12 Hz)
1.26-1.37 (two t, 6H, OCH2CH3, J = 7.12 Hz), 3.93 (s, 3H, OCH3), 4.11-4.31 (two q, 4H,
OCH2CH3, J = 7.08 Hz), 7.21-7.84 (m, 9H, Ar-H), 8.71 (s, 1H, H at C2), 9.31-9.34 (d, 1H, =CH,
J = 12.08 Hz), 10.82-10.85 (d, 1H, NH, J = 12 Hz)
1.24-1.35 (two t, 6H, OCH2CH3, J = 7.12 Hz), 3.90 (s, 3H, OCH3), 4.08-4.28 (two q, 4H,
OCH2CH3, J = 7.12 Hz), 7.20-7.95 (m, 8H, Ar-H), 8.69(s, 1H, H at C2), 9.30-9.33 (d, 1H, =CH, J
= 12.24 Hz), 10.80-10.83 (d, 1H, NH, J = 12.12 Hz)
1.27-1.38 (two t, 6H, OCH2CH3, J = 7.12 Hz), 4.10-4.30 (two q, 4H, OCH2CH3, J = 7.08 Hz),
7.19-7.81 (m, 10H, Ar-H), 8.67 (s, 1H, H at C2), 9.31-9.34 (d, 1H, =CH, J = 12.16 Hz), 10.82-
10.85 (d, 1H, NH, J = 12.08 Hz)
1.25-1.36 (two t, 6H, OCH2CH3, J = 7.12 Hz), 4.11-4.31 (two q, 4H, OCH2CH3, J = 7.12 Hz),
7.24-7.96 (m, 9H, Ar-H), 8.71 (s, 1H, H at C2), 9.29-9.32 (d, 1H, =CH, J = 12.20 Hz), 10.80-
10.85 (d, 1H, NH, J = 12.08 Hz)
1.24-1.35 (two t, 6H, OCH2CH3, J = 7.08 Hz), 4.08-4.28 (two q, 4H, OCH2CH3, J = 7.12 Hz),
7.26-7.90 (m, 9H, Ar-H), 8.69 (s, 1H, H at C2), 9.30-9.33 (d, 1H, =CH, J = 12.24 Hz), 10.79-
10.82(d, 1H, NH, J = 12.08 Hz)
1.23-1.34 (two t, 6H, OCH2CH3, J = 7.12 Hz), 4.11-4.31 (two q, 4H, OCH2CH3, J = 7.16 Hz),
7.20-7.79 (m, 8H, Ar-H), 8.69 (s, 1H, H at C2), 9.32-9.35 (d, 1H, =CH, J = 12.20 Hz), 10.81-
10.84 (d, 1H, NH, J = 12 Hz)
4g
4h
4i
4j
4k
4l
4m
Table 3 (continued)
IR and 1H NMR Spectral Data for Compounds 5a-5m
Compound
No.
5a
IR (KBr) cm-1
1H NMR (DMSO-d6 / TMS) (ꢀ ppm)
1740,1692,1600,1500
1740,1702,1592,1520
1740,1704,1604,1516
1736,1700,1600,1512
1740,1704,1610,1500
1740,1704,1596,1508
1740,1692,1604,1510
1.39-1.42 (t, 3H, OCH2CH3, J = 7.12 Hz), 4.38-4.43 (q, 2H, OCH2CH3, J = 7.12 Hz), 7.06-7.60
(m, 11H, Ar-H), 8.99 (s, 1H, H at C2), 9.77 (s, 1H, H at C6)
1.38-1.41 (t, 3H, OCH2CH3, J = 7.08 Hz), 3.91 (s, 3H, OCH3), 4.39-4.44 (q, 2H, OCH2CH3, J =
7.12 Hz), 7.02-7.64 (m, 10H, Ar-H), 9.01 (s, 1H, H at C2), 9.76 (s, 1H, H at C6)
1.37-1.40 (t, 3H, OCH2CH3, J = 7.16 Hz), 4.38-4.43 (q, 2H, OCH2CH3, J = 7.12 Hz), 7.01-7.65
(m, 10H, Ar-H), 9.01 (s, 1H, H at C2), 9.75 (s, 1H, H at C6)
1.39-1.42 (t, 3H, OCH2CH3, J = 7.08 Hz), 4.37-4.42 (q, 2H, OCH2CH3, J = 7.08 Hz), 7.02-7.69
(m, 10H, Ar-H), 9.03 (s, 1H, H at C2), 9.76 (s, 1H, H at C6)
1.36-1.39 (t, 3H, OCH2CH3, J = 7.12 Hz), 4.38-4.43 (q, 2H, OCH2CH3, J = 7.16 Hz), 7.01-7.67
(m, 9H, Ar-H), 9.01 (s, 1H, H at C2), 9.78 (s, 1H, H at C6)
5b
5c
5d
5e
5f
1.37-1.40 (t, 3H, OCH2CH3, J = 7.12 Hz), 3.89 (s, 3H, OCH3), 4.39-4.44(q, 2H, CH2CH3, J =
7.12 Hz), 7.01-7.67 (m, 10H, Ar-H), 9.02 (s, 1H, H at C2), 9.76 (s, 1H, H at C6)
1.39-1.42 (t, 3H, OCH2CH3, J = 7.08 Hz), 3.89(s, 6H, OCH3), 4.37-4.42 (q, 2H, OCH2CH3, J =
7.12 Hz), 7.01-7.67 (m, 9H, Ar-H), 9.02 (s, 1H, H at C2), 9.76 (s, 1H, H at C6)
5g

1348
N. D. Desai
Vol 43
Table 3 (continued)
Compound
No.
5h
IR (KBr) cm-1
1H NMR (DMSO-d6 / TMS) (ꢀ ppm)
1736,1700,1616,1512
1740,1692,1604,1520
1736,1696,1600,1508
1740,1696,1608,1504
1744,1700,1610,1512
1736,1696,1604,1508
1.37-1.40 (t, 3H, OCH2CH3, J = 7.16 Hz), 3.90 (s, 3H, OCH3), 4.36-4.41 (q, 2H, OCH2CH3, J =
7.16 Hz), 7.07-7.63 (m, 9H, Ar-H), 9.01 (s, 1H, H at C2), 9.78 (s, 1H, H at C6)
1.38-1.41 (t, 3H, OCH2CH3, J = 7.12 Hz), 3.92 (s, 3H, OCH3), 4.39-4.44 (q, 2H, OCH2CH3, J =
7.12 Hz), 6.99-7.61 (m, 8H, Ar-H), 9.04 (s, 1H, H at C2), 9.77 (s, 1H, H at C6)
1.36-1.39 (t, 3H, OCH2CH3, J = 7.08 Hz), 4.38-4.43 (q, 2H, OCH2CH3, J = 7.12 Hz), 7.01-7.67
(m, 10H, Ar-H), 9.01(s, 1H, H at C2), 9.78 (s, 1H, H at C6)
1.39-1.42 (t, 3H, OCH2CH3, J = 7.04 Hz), 4.37-4.42 (q, 2H, OCH2CH3, J = 7.08 Hz), 7.05-7.61
(m, 9H, Ar-H), 9.02 (s, 1H, H at C2), 9.74 (s, 1H, H at C6)
1.36-1.39 (t, 3H, OCH2CH3, J = 7.12 Hz), 4.38-4.43 (q, 2H, OCH2CH3, J = 7.12 Hz), 7.03-7.60
(m, 9H, Ar-H), 9.05 (s, 1H, H at C2), 9.72 (s, 1H, H at C6)
5i
5j
5k
5l
5m
1.38-1.41 (t, 3H, OCH2CH3, J = 7.12 Hz), 4.36-4.41 (q, 2H, OCH2CH3, J = 7.16 Hz), 7.03-7.60
(m, 8H, Ar-H), 8.99(s, 1H, H at C2), 9.74 (s, 1H, H at C6)
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9, 1237 (2005).
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J. Org. Chem., 53, 5464 (1988).
Acknowledgement.
We wish to thank the Regional Sophisticated Instrumentation
1
Center, Central Drug Research Institute, Lucknow, India for H
NMR and mass spectral analysis and to the Director Loyola
Center for R & D, St. Xavier’s College, Ahmedabad for the
facility to carry out this work.
[9] C. G. Dave and M. C. Shukla, J. Heterocycl. Chem., 34, 1805
(1997).
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Storing: Keep in a tightly closed light-resistant container, stored in a
cool, dry, ventilated area. Other Precautions: Do not
expose to open
flames or hot surface it may result in to toxic fumes of chlorides, carbon
monoxide and phosgene in fire.
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