Design and synthesis of 1-aroyl-2-ylidene hydrazines under conventional and microwave irradiation conditions and their cytotoxic activities

Article abstract of DOI:10.1590/S0103-50532010000100015

We report the design and synthesis of 1-aroyl-2-(alkenyl/aryl)idene hydrazines as hybrid molecules derived from mefenamic acid and substituted hydrazones. A number of compounds based on this new scaffold were prepared in good yields. The key intermediate

Full text of DOI:10.1590/S0103-50532010000100015

J. Braz. Chem. Soc., Vol. 21, No. 1, 98-104, 2010.
Printed in Brazil - ©2010 Sociedade Brasileira de Química
0103 - 5053 $6.00+0.00
Design and Synthesis of 1-Aroyl-2-ylidene Hydrazines under Conventional
and Microwave Irradiation Conditions and their Cytotoxic Activities
Lingam Venkata Reddy,a Alishetty Suman,a Syed Sultan Beevi,b
Lakshmi Narasu Mangamoori,b Khagga Mukkantia and Sarbani Pal*,c
aCentre for Environment, JNT University, Kukatpally, Hyderabad-500072, India
bCentre for Biotechnology, Institute of Science and Technology, Kukatpally, JNT University,
Hyderabad-500072, India
cDepartment of Chemistry, MNR Degree and PG College, Kukatpally, Hyderabad-500072, India
Reportamos o planejamento e síntese de 1-aroil-2-(alquenil/aril)ideno hidrazinas como
moléculas hibridas derivadas do ácido mafenamico e hidrazonas substituídas. Diferentes compostos
baseados nesse novo plano foram preparados com bons rendimentos. O intermediário chave,
N-acilidrazina, preparado a partir do ácido mafenamico, reagiu com uma variedade de aldeídos,
sob condições experimentais convencionais ou com irradiação de microondas. Nesta última, que
requer pequenos tempos reacionais, pode-se eliminar o uso de solvente e não é necessário catalisador
ácido ou suporte sólido. Alguns compostos sintetisados mostraram atividades citotóxicas in vitro.
We report the design and synthesis of 1-aroyl-2-(alkenyl/aryl)idene hydrazines as hybrid
molecules derived from mefenamic acid and substituted hydrazones. A number of compounds
based on this new scaffold were prepared in good yields. The key intermediate N-acylhydrazine,
prepared from mefenamic acid, was coupled with a variety of aldehydes under conventional as
well as microwave irradiation conditions. The second approach, that requires short reaction time,
can be carried out under a solvent free condition and does not require the use of an acid catalyst
or solid support. Some of the compounds synthesized showed cytotoxic activities in vitro.
Keywords: mefenamic acid, hydrazine, N-acylhydrazine, microwave, solvent-free synthesis,
cytotoxicity
Introduction
medical researchers,2 because of their unique structural
feature due to the presence of azomethine hydrogen
and a range of pharmacological properties especially
antitumoral activities. For example compound 2 (Figure 1)
showed promising cytotoxicity3 when tested in vitro. In
our strategy4 to develop safer molecule we decided to
combine some of the structural features of mefenamic
acid and substituted hydrazones in a single molecule,
e.g., 1-aroyl- 2-ylidene hydrazines A (see Figure 2). The
Fenamates represent a group of non steroidal anti-
inflammatory drugs (NSAIDs), e.g. mefenamic acid,
tolfenamic acid, flufenamic acid, niflumic acid etc, that
belong to N-aryl amino benzoic acid class of compounds.
Mefenamic acid1 (1) (Figure 1), one of the most regularly
used fenamates for the treatment of pain, is believed
to work by blocking the action of (i) cyclooxygenase
(COX-1 and COX-2) involved in the production of
prostaglandins (that are produced in response to
injury or certain diseases and cause pain, swelling and
inflammation) or (ii) prostaglandins directly after they
have already been formed thereby relieving pain and
inflammation. Hydrazones and substituted hydrazones
on the other hand continue to attract the attention of the
Ph
HO
O
N
N
Me
Cl
H
N
Me
N
NH
O
O2N
Mefenamic acid (1)
2
Figure 1. Mefenamic acid (1) and substituted hydrazone (2) of
pharmacological interest.
*e-mail: sarbani277@yahoo.com

Vol. 21, No. 1, 2010
Reddy et al.
99
No acid group
O
environment friendly reaction conditions. Because of our
interest on the development of environmentally benign
methods7,8 for synthesizing compounds of potential
pharmacological significances we conducted the solvent
free synthesis of 9 under microwave irradiation.9 The
solvent free synthesis afforded the desired product 9a-h
within few minutes in excellent yields with a high degree
of regioselectivity (Method B, Scheme 1). The results of
our study along with the comparison of yields of products
obtained via conventional and microwave method has been
presented in Table 1.
Moiety
containing
azomethine
hydrogen
N
R
Mefenamic acid
N
(1)
H
NH
Me
Me
H
N
N
O
A
Figure 2. Design of hybrid molecules of potential pharmacological
interest.
hybrid molecule A was expected to be cytotoxic due to
the presence of hydrazone moiety. Moreover, because of
the lack of acid group this molecule was expected to be
free from the side effects of 1 such as gastrointestinal
side effects. Herein, we report the synthesis of a series
of mefenamic acid based 2-ylidene hydrazine derivatives
of potential biological significances via straightforward
condensation of the key intermediate N-acylhydrazine
with an appropriate and commercially available aldehyde.
As shown in Table 1 that a variety of aldehydes
including aryl (entries 1-5, 7 and 8, Table 1) and alkenyl
(entry 6, Table 1) were employed and yields of products
were not affected significantly by the presence of
substituents like halo, hydroxyl, alkoxy, amino or aldehyde
on the benzene ring. A highly conjugated derivative 9f
(entry 6, Table 1) was obtained when 2-butenal was used.
The reaction time to prepare 9a-h generally varied from 7
to 13 h for MethodA and 1.0 to 2.5 min in case of Method
B. Both the methods produced reaction products in good
yields without generating any significant side products.
It is therefore, clear that the microwave-mediated method
did not differ from the conventional method in terms of
product nature. However, it reduced the reaction time
remarkably and avoided the use of environmentally
harmful organic solvents as well as prolonged heating
conditions. Moreover, unlike earlier method9 the present
microwave-mediated process was free from the use of
acid catalyst and solid support. Thus, Method B proved
to be more practical and has potential for further use.
Notably, synthesis of the same class of compounds from
N-acylhydrazine (7) has been reported earlier.10 However,
this method which involved the reaction of compound 7
with aromatic aldehydes in ethanol in the presence of
catalytic amount of HCl provided the desired products in
low to moderate yields (14-76%, only one compound was
isolated in 90% yield). Moreover, apart from the use of
environmentally harmful HCl this method required longer
(0.5-1.0 h) reaction time. Nevertheless, the structures
of all the new compounds synthesized were confirmed
Results and Discussion
The key intermediate 7 required for our synthesis
was prepared from mefenamic acid 1 (Scheme 1). Thus,
esterification of 1 with methanol in the presence of
concentrated sulphuric acid followed by the treatment with
hydrazine hydrate in methanol gave the compound 7 in
75% yield. Reaction of 7 with 1.1 equivalent of aldehydes
(8a-h) in 1,4-dioxane at room temperature afforded the
compounds 9a-h (Method A, Scheme 1). During the
course of our studies we observed that although aromatic
and conjugated aldehydes reacted with the acid hydrazide
7 under conventional method to produce the desired
product in good yields, the duration of the reaction,
however, was 8-10 h. In order to reduce the reaction
time significantly we decided to conduct the reaction
of 7 with 8a-h under microwave irradiations. Recently
organic transformations, under solvent free microwave
irradiation conditions,5,6 has gained extensive applications
due to many convenient advantages coupled with superior
reaction rates, high yields, improved selectivity and
O
N
R
N
H
COOMe
CONHNH2
NH
b
c
a
Me
Me
HN
HN
1
Me
Me
Me
Me
9
7
6
Scheme 1. Synthesis of 1-aroyl-2-(alkenyl/aryl)idene hydrazines (9). Reagents and conditions: (a) MeOH/Conc. H2SO4; (b) N2H4.H2O; (c) Method A:
RCHO (8) / 1,4-dioxane, rt or Method B: RCHO (8) / MW.

100
Design and Synthesis of 1-Aroyl-2-ylidene Hydrazines
J. Braz. Chem. Soc.
Table 1. Preparation of 1-aroyl-2-(alkenyl/aryl)idene hydrazines (9) from N-acylhydrazine (7) under conventional and microwave irradiation condition
time/Yielda (%)
Entry
RCHO (8)
Products (9)
OH
Conventional reactionb
Microwave reaction
O
H
CHO
N
N
1
9a
9b
9c
8h / 72
2.5 min / 85
NH
OH
Me
Me
O
CHO
Cl
H
N
N
Cl
2
3
10h / 81
1.5 min / 84
NH
Me
Me
OHC
O
H
CHO
N
N
OHC
11h / 72
2.0 min / 84
NH
Me
Me
O
CHO
OMe
H
N
N
OMe
4
5
6
9d
9e
9f
13h / 70
9.5h / 83
8h / 79
2.5 min / 77
1.0 min / 85
1.0 min / 87
NH
Me
Me
O
H
CHO
N
N
NO2
NH
NO2
Me
Me
O
H
N
N
CH CH CH Me
OHC
NH
Me
Me
Me
HO
N
O
H
N
OH
OHC
7
8
9g
9h
10.5h / 73
2.5 min / 80
NH
Me
Me
H2N
O
H
N
NH2
N
OHC
12h / 75
2.0 min / 81
NH
Me
Me
aYield of isolated product; bAll the reactions were carried out at room temperature.

Vol. 21, No. 1, 2010
Reddy et al.
101
Table 2. MTT assay result of ylidene acid hydrazides (9)
% of cell death at various doses
Entry
Compds.
1 µg
17.2
18.9
18.1
27.9
34.8
2 µg
21.7
20.2
21.7
29.3
38.1
4 µg
30.1
24.8
25.3
31.6
43.6
6 µg
36.7
25.3
31.6
33.5
45.7
8 µg
47.2
31.6
33.5
33.5
46.1
10 µg
49.8
32.4
nd
1
9a
9b
9e
9f
2
3
4
34.7
54.1
5
9g
nd = not done.
by spectral (IR, NMR and MS) and analytical data. The
NH hydrogens and azomethine hydrogens appeared at
d 8-12 ppm in the 1H NMR spectra whereas the presence
of C=N and C=O group was indicated by signals at 1580
and 1635-1625 cm-1 in the IR spectra. We attempted to
determine the geometry of –C=C– of compound 9f. Based
on (i) the nature of the reactant used, i.e., (Z)-but-3-enal
and (ii) the –C=C– moiety not being the reaction site it
is expected that this double bond would maintain the
same geometry in the corresponding product. This was
supported by the 1H NMR data (J 8 Hz) of compound 9f.
Some of the compounds synthesized were tested
against human lung adenocarcinoma cell line (A549)
in vitro to asses their cytotoxic activities and the results
are summarized in Table 2. As evident from Table 2, that
all the compounds showed moderate cytotoxic activities
particularly at higher dose. Compound 9g (Entry 5, Table
2) was found to be the most active in this series followed by
9a (Entry 1, Table 2) indicating the important role played
by phenol moiety towards cytotoxic activities.
Experimental
General
Melting points were determined by open glass capillary
method on a Cintex melting point apparatus and are
uncorrected. IR spectra were recorded on a Perkin-Elmer
spectrometer in KBr pellets. 1H NMR spectra were recorded
on a Bruker ACF-300 machine and a Varian 300 MHz
spectrometer using DMSO-d6, with reference to tetra-
methylsilane as internal reference. 13C NMR spectra were
recorded on a 75 MHz spectrometer. Microwave irradiation
was carried out in a domestic micro oven operating at
2450 MHz. Elemental analysis were performed by Varian
3LV analyzer series CHN analyzer. Mass spectra were
recorded on a Jeol JMC D-300 instrument by using Electron
ionization at 70 ev. All reactions were monitored by TLC
on pre-coated silica gel plates. Column chromatography
was performed on 100-200 mesh silica gel (SRL, India)
using 10-20 fold excess (by weight) of the crude product.
The organic extracts were dried over anhydrous Na2SO4.
All solvents were distilled before use. Mefenamic acid (1)
and all the aldehydes used are commercially available.
Conclusion
In summary, we have described design and synthesis of
a variety of novel hybrid molecules, i.e., 1-aroyl-2-(alkenyl/
aryl)idene hydrazines derived from an NSAID, mefenamic
acid and pharmacologically active substituted hydrazones.
The synthesis of these compounds involves the use of a
key intermediate, i.e., N-acylhydrazine that was prepared
readily from mefenamic acid following a simple two-step
process. Coupling of the acid hydrazide with a variety
of aldehydes was studied under conventional as well as
microwave irradiation conditions. The second approach
showed significant advantages over the previous one by
decreasing the reaction time remarkably and avoiding the
use of environmentally harmful organic solvents. Due to
the lack of acid group and the presence of azomethine
hydrogen the present novel class of 1-aroyl-2-ylidene
hydrazines is expected to be safer and has potential for
further pharmacological evaluation.
Preparation of methyl 2-(2,3-dimethylanilino) benzoate (6)
To a solution of mefenamic acid (5.0 g, 0.02 mol) in
MeOH (15 mL) was added conc. H2SO4 (1.5 mL) carefully.
The solution was refluxed for 16-18 h and the progress
of the reaction was monitored by TLC. After completion
of the reaction, solvent was evaporated. The crude was
added to water, neutralized by 2 mol L-1 NaOH (until pH
is 7.0) and finally extracted with CHCl3 (3 × 25 mL). The
combined chloroform layer was washed with brine, dried
over anhydrous Na2SO4 and concentrated under reduced
pressure. The residue obtained was purified by column
chromatography on a silica gel column to afford the desired
product as a white solid (4.1 g, 80% yield); mp 96-98 ºC,
Rf = 0.80 (3:2 ethyl acetate/n-hexane) MS m/z 256 (M+,
100%), 240.1 (M-15); IR νmax/cm-1 (KBr): 1686; 1H NMR

102
Design and Synthesis of 1-Aroyl-2-ylidene Hydrazines
J. Braz. Chem. Soc.
(DMSO-d6, 300 MHz) d 2.09 (s, 3H), 2.28 (s, 3H), 3.86 (s,
3H), 6.65-6.72 (m, 2H), 7.05-7.11 (m, 3H), 7.30-7.34 (m,
1H), 7.87-7.89 (m, 1H), 9.16 (s, NH); Elemental analysis
found C, 75.31; H, 6.75; N, 5.33; Calc. for C16H17NO2; C,
75.27; H, 6.71; N, 5.49.
9a: light green solid; mp 218-220 ºC, Rf = 0.30 (ethyl
acetate/n-hexane, 3:2); MS m/z 360 (M+, 100%); 1H NMR
(DMSO-d6, 300 MHz) d 2.11 (s, 3H), 2.26 (s, 3H), 6.85-
6.77 (m, 3H), 7.31-6.93 (m, 7H), 7.71 (d, J 12 Hz, 1H),
8.32 (bs, 1H), 9.24 (bs, 1H), 9.63 (s, 1H), 11.81 (s, 1H);
13C NMR (DMSO-d6, 75 MHz) d 13.4, 20.1, 112.5, 114.0,
115.8, 116.7, 117.3, 118.6, 120.0, 125.2; 125.8; 128.8,
129.5, 129.7, 132.4, 135.5, 137.6, 138.9, 146.5, 157.6;
Elemental analysis found C, 73.29; H, 5.75; N 11.35. Calc.
for C22H21N3O2; C, 73.52; H, 5.89; N, 11.69.
Preparation of 2-(2,3-dimethylphenylamino)benzo-
hydrazide (7)
To a solution of ester 6 (1 g, 0.004 mol) in EtOH
(10 mL) was added hydrazine hydrate (2 mL) dropwise
and the solution was stirred. The temperature of the mixture
was raised gradually to 95-100 ºC and was maintained for
12 h. The reaction mixture was then concentrated under
reduced pressure and the residue was diluted with water
(10 mL). The aqueous layer was extracted with chloroform
(3 × 25 mL). The organic layers were collected, combined,
washed with brine (10 mL), dried over anhydrous Na2SO4
and concentrated under reduced pressure. The solid
obtained was purified by crystallization from EtOH, filtered
and dried to give the desired compound as a yellow solid
(0.82 g, 80% yield); mp 118-120 ºC, Rf = 0.3 (3:2 ethyl
9b: white solid; mp 196-198 ºC; Rf = 0.65 (ethyl
acetate/n-hexane, 3:2); MS m/z 376 (M+, 100%), 378
(M+2) in the ratio 3:1; IR νmax/cm-1 (KBr): 1634, 1581; 1H
NMR (DMSO-d6, 300 MHz) d 2.10 (s, 3H), 2.26 (s, 3H),
6.84-6.77 (m, 3H), 6.93-7.31 (m, 7H), 7.72 (d, J 12 Hz,
1H), 8.40 (bs, 1H), 9.23 (bs, 1H), 11.94 (s, 1H); 13C NMR
(DMSO-d6, 75 MHz) d 13.4, 20.1, 114.1, 116.7, 120.1,
125.3, 125.8, 128.6, 128.8, 129.6, 132.5, 133.2, 134.4,
137.6, 138.9, 146.3, 146.6, 165.5; Elemental analysis
found C, 73.61; H, 5.90; N 11.41. Calc. for C22H20N3OCl;
C, 73.52; H, 5.89; N, 11.69.
1
acetate/n-hexane); MS m/z 256 (M+, 100%); H NMR
(DMSO-d6, 300 MHz) d 2.09 (s, 3H), 2.26 (s, 3H), 6.67
(d, J 4 Hz, 1H), 6.67- 7.03 (m, 3H), 7.10-7.25 (m, 2H),
7.30-7.40 (m, 1H), 7.65-7.68 (m, 1H), 9.0 (s, 1H), 9.40 (s,
1H), 9.80 (s, 1H), 10.51 (s, 1H).
9c: yellow solid; mp 186-188 ºC; Rf = 0.56 (ethyl
acetate/n-hexane, 3:2);MSm/z372(M+, 100%);IRνmax/cm-1
(KBr): 1680, 1625, 1581; 1H NMR (DMSO-d6, 300 MHz)
d 2.11 (s, 3H), 2.27 (s, 3H), 6.78 (t, J 8 Hz, 1H), 6.85 (d, J
8 Hz, 1H), 6.95 (d, J 6.9 Hz, 1H), 7.07-7.09 (m, 2H), 7.29
(t, J 8 Hz, 1H), 7.52 (t, J 8 Hz, 1H), 7.75 (t, J 16 Hz, 1H),
7.88 (d, J 6 Hz, 1H), 8.06-7.90 (m, 1H), 8.10 (m, 1H), 9.17
(s, 1H), 9.30 (s, 1H), 12.10 (s, 1H); Elemental analysis
found C, 74.49; H, 5.75; N 11.09. Calc. for C23H21N3O2;
C, 74.37; H, 5.70; N, 11.31.
Preparation of 1-aroyl-2-(alkenyl/aryl)idene hydrazines
(9a-g)
Conventional method (Method A)
A solution of the compound 7 (2.56 g, 0.01 mol) and
compound 8a-g (0.011 mole) in 1,4-dioxane (15 mL) was
stirred at room temperature for the time indicated inTable 1.
The progress of the reaction was monitored by TLC. After
completion, the reaction mixture was diluted by using ice
cold water (25 mL) with stirring. The solid separated was
filtered, washed with ice cold water and recrystallised from
EtOH to afford the expected product (9a-g).
9d: white solid; mp 210-212 ºC, Rf = 0.53 (ethyl acetate/
n-hexane, 3:2); MS m/z 374 (M+, 100%); IR νmax/cm-1
(KBr): 1628, 1605, 1576; 1H NMR (DMSO-d6, 300 MHz)
d 2.11 (s, 3H), 2.27 (s, 3H), 3.80 (s, 3H), 7.07-6.75 (m,
8H), 7.25-7.30 (m, 1H), 7.63-7.71 (m, 2H), 8.34 (s, 1H),
9.23 (s, 1H), 11.73 (s, 1H); Elemental analysis found C,
73.89; H, 6.25; N 11.77. Calc. for C23H23N3O2; C, 73.97;
H, 6.21; N, 11.69.
Microwave method (Method B)
A mixture of compound 7 (0.01 mol) and aldehydes
8a-g (0.011 mol) were taken in a 100 mL beaker and stirred
for 5 min to make it homogeneous. The mixture was then
exposed to microwave irradiation at 2450 MHz frequency
for the time indicated inTable 1 (the reaction was monitored
at an interval of 30 s using TLC). After completion, the
mixture was cooled to room temperature and treated with
EtOH (10 mL). The solid separated was filtered and dried
to furnish the pure expected product (9a-g).
9e: yellow solid; mp. 216-218 ºC; Rf = 0.37 (ethyl
acetate/n-hexane, 3:2);MSm/z389(M+, 100%);IRνmax/cm-1
(KBr): 1635, 1580, 1552; 1H NMR (DMSO-d6, 300 MHz)
d 2.12 (s, 3H), 2.28 (s, 3H), 6.77-7.09 (m, 6H), 7.28-7.30
(m, 1H), 7.64-7.83 (m, 2H), 8.06-8.13 (m, 2H), 8.83 (s, 1H),
9.29 (bs, 1H), 12.21 (s, 1H); Elemental analysis found C,
68.16; H, 5.15; N 14.25. Calc. for C22H20N4O3; C, 68.03;
H, 5.19; N, 14.42.

Vol. 21, No. 1, 2010
Reddy et al.
103
9f: light yellow solid; mp 168-170 ºC, Rf = 0.37 (ethyl
acetate/n-hexane, 3:2);MSm/z308(M+, 100%);IRνmax/cm-1
(KBr): 1628, 1581, 1554, 1505; 1H NMR (DMSO-d6, 300
MHz) d 1.87 (s, 3H), 2.09 (s, 3H), 2.26 (s, 3H), 6.04-6.30
(m, 2H), 6.73-6.83 (m, 2H), 6.93-7.06 (m, 1H), 7.10 (m,
2H), 7.26 (t, J 6 Hz, 1H), 7.63 (d, J 9 Hz, 1H), 7.99 (d, J 8
Hz, 1H), 9.20 (s, 1H), 11.53 (s, 1H); 13C NMR (DMSO-d6,
75 MHz) d 13.3, 18.2, 20.1, 116.5, 117.0, 119.9, 122.3,
125.3, 125.9, 126.7, 128.5, 128.6, 129.5, 132.4, 138.9,
146.4, 150.3; Elemental analysis found C, 74.39; H, 6.85;
N 13.60. Calc. for C19H21N3O; C, 74.24; H, 6.89; N, 13.67.
MTT assay for cytotoxicity: The viability of the cells
was assessed by MTT (3, 4, 5-dimethylthiazol-2-yl)-2-5-
diphenyltetrazolium bromide) assay, which is based on the
reduction of MTT by the mitochondrial dehydrogenase
of intact cells to a purple formazan product (15?).15 Cells
(1 × 104) were plated in a 96-well plate. After 24 h, they
were treated with different concentration (0-10 µg) of
different test compounds diluted appropriately with culture
media for 48 h. Cells grown in media containing equivalent
amount of DMSO served as positive control and cells in
medium without any supplementation were used as negative
control. After the treatment, media containing compound
were carefully removed. 100 µL of 0.4 mg mL-1 MTT in
PBS was added to each well and incubated in the dark
for 4 h. 100 µL of DMSO was added to each well and
kept in an incubator for 4 h for dissolution of the formed
formazan crystals.Amount of formazan was determined by
measuring the absorbance at 540 nm using an ELISA plate
reader. The data were presented as percent post treatment
recovery (% of live cells), whereas the absorbance from
non-treated control cells was defined as 100% live cells.
9g: cream solid; mp 164-166 ºC; Rf = 0.31 (ethyl acetate/
n-hexane, 3:2); MS m/z 360 (M+, 100%); IR νmax/cm-1
(KBr): 1651, 1625, 1607, 1574; 1H NMR (DMSO-d6, 300
MHz) d 2.11 (s, 3H), 2.27 (s, 3H), 6.76-7.08 (m, 7H), 7.28-
7.41 (m, 2H), 7.51 (d, J 6 Hz, 1H), 7.74 (d, J 7 Hz, 1H),
8.60 (s, 1H), 9.27 (s, 1H), 11.28 (s, 1H), 12.09 (bs, 1H);
13C NMR (DMSO-d6, 75 MHz) d 13.5, 20.1, 116.6, 118.6,
119.2, 120.6, 121.2, 122.1, 124.5, 125.8, 127.8, 129.4,
130.0, 131.2, 133.7, 135.6, 137.6, 138.8, 147.0, 149.0,
157.4, 165.0; Elemental analysis found C, 73.66; H, 5.85;
N 11.55. Calc. for C22H21N3O2; C, 73.52; H, 5.89; N, 11.69.
Acknowledgment
9h: yellow solid; mp 190-192 ºC; Rf = 0.53 (ethyl
acetate/n-hexane, 3:2);MSm/z359(M+, 100%);IRνmax/cm-1
(KBr): 1636, 1567, 1523; 1H NMR (DMSO-d6, 300 MHz)
d 2.12 (s, 3H), 2.28 (s, 3H), 6.57-7.17 (m, 11H), 7.30 (t, J
8 Hz, 1H), 7.82 (d, J 6 Hz, 1H), 8.48 (s, 1H), 9.29 (s, 1H),
11.78 (s, 1H); 13C NMR (DMSO-d6, 75 MHz) d 16.3, 22.9,
117.5, 118.3, 120.0, 123.1, 128.6, 129.4, 131.3, 132.6,
133.0, 135.1, 136.1, 141.7, 143.9, 149.4, 150.5, 153.8,
167.7; Elemental analysis found C, 73.62; H, 6.25; N 15.69.
Calc. for C22H22N4O; C, 73.72; H, 6.19; N, 15.63.
The author (S. Pal) thanks Mr. M. N. Raju, the
chairman of M. N. R. Educational Trust for his constant
encouragement.
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104
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Received: May 1, 2009
Web Release Date: October 16, 2009