An efficient synthesis and biological testing of novel 3-chloro-4-aryl-1- (4-(phenyldiazenyl)phenyl)azetidin-2-ones

Article abstract of DOI:10.1002/jhet.459

N-Benzylidene-4-(phenyldiazenyl)aniline (Ia-Ij) has been prepared from p-aminoazobenzene with different aromatic aldehydes under microwave irradiation, which on further treatment with chloro acetic acid and POCl₃ in the presence of triethyl ami

Full text of DOI:10.1002/jhet.459

November 2010
An Efficient Synthesis and Biological Testing of Novel
3-Chloro-4-aryl-1-(4-(phenyldiazenyl)phenyl)azetidin-2-ones
1361
Himani N. Chopde, Ramakanth Pagadala, Jyotsna S. Meshram,*
and Venkateshwarlu Jetti
Department of Chemistry, Rashtrasant Tukadoji Maharaj Nagpur University, Nagpur,
Maharashtra 440 033, India
*E-mail: drjsmeshram@rediffmail.com
Received December 15, 2009
DOI 10.1002/jhet.459
Published online 24 August 2010 in Wiley Online Library (wileyonlinelibrary.com).
N-Benzylidene-4-(phenyldiazenyl)aniline (Ia–Ij) has been prepared from p-aminoazobenzene with dif-
ferent aromatic aldehydes under microwave irradiation, which on further treatment with chloro acetic
acid and POCl3 in the presence of triethyl amine gave the title compounds. The structure of the com-
pounds has been confirmed by spectroscopic techniques (IR and 1H NMR) and elemental analysis.
These azetidinones analogues were screened for their antimicrobial activities against strains of different
microorganisms. Some of the compounds displayed the promising antibacterial activities against some
bacterial strains.
J. Heterocyclic Chem., 47, 1361 (2010).
INTRODUCTION
and reviewed several times [15]. The hydroxamate cy-
clization [16], the metalloester enolate-imine condensa-
tion [17], the chromium carbene-imine reaction [18], the
isocyanate-alkene cycloaddition [19], and the ketene-
imine cycloaddition [20] are the approaches most often
used for the construction of the azetidin-2-one ring. In
particular, the most common method for the synthesis of
2-azetidinone is the Staudinger Ketene-imine cycloaddi-
tion, which involves the reaction of imine (Schiff Base)
with acid chloride in the presence of tertiary base [21].
This reaction, however, depends on many factors includ-
ing temperature and reaction time, which often needs to
be optimized [22,23].
The b-lactam skeleton is the key structural element of
the most widely used family of antimicrobial agents to
date, the b-lactam antibiotics, which includes as repre-
sentative structural classes (Fig. 1) the Penams 1,
Cephems 2, Penems 3, Monobactams 4, Carbapenems 5,
and Trinems 6, among others [1]. The first member of
this class of compounds was synthesized by Staudinger
in 1907 [2]. An interesting group of b-lactams are the
monocyclic b-lactams, which are molecules that do not
contain another ring fused to the b-lactam. The develop-
ment of several synthetic 2-azetidinone was due to the
growing resistant of bacteria toward the b-lactam antibi-
otics and need for medicines with a more specific anti-
bacterial activities [3,4]. A large number of monocyclic
b-lactams reported to have some other types of biologi-
cal activity such as antifungal, antitubercular, antitumor,
anti-inflamatory, anticonvulsant, cholesterol absorption
inhibition, and enzyme inhibition activity [5–10].
Hence, to further assess the pharmacological activities
of these class of molecules, it was thought worthwhile
to synthesize some new derivatives of b-lactam hetero-
cycles by incorporating the p-aminoazobenzene and
2-azetidinone moieties in a single framework. We herein
report a novel, convenient, and highly efficient method
for the preparation of 3-chloro-4-(aryl)-1-(4-(phenyldia-
zenyl)phenyl)azetidin-2-one IIa–IIj in good yields
involving two steps. It involves the formation of differ-
ent Schiff’s bases Ia–Ij of p-aminoazobenzene and aro-
matic aldehydes followed by the cycloaddition reaction
Because of such versatile applications, these moieties
always attracted the interest of synthetic and medicinal
organic chemists [11–14]. A large number of chemical
methods for the production of b-lactams have been
developed, and the topic has been amply documented
C
V
2010 HeteroCorporation

1362
H. N. Chopde, R. Pagadala, J. S. Meshram, and V. Jetti
Vol 47
RESULTS AND DISCUSSION
As evident from data presented in Table 1, we were
able to obtain N-arylbenzylidene-4-(phenyldiazenyl)ani-
line Ia–Ij in good yields by using neat conditions under
microwave irradiation in presence of solvent and also in
solvent free conditions when compared to that of con-
ventional reflux reactions in ethanol. The comparison of
isolated yields and reaction time of the three conditions
used showed microwave-assisted solvent-free reactions
as the most efficient synthetic method in terms of
energy and time consumption. All the compounds syn-
thesized were adequately characterized by their elemen-
tal analysis and spectral techniques such as IR, 1H
NMR, and mass spectra.
Figure 1. Some representative structural classes of b-lactam
antibiotics.
Antibacterial activity. Antibacterial activities of all
the compounds were studied against nine different bac-
terial strains (E. coli (mixed), B. subtilis, Pseudomonas
sp., S. aureus, P.vulageris, Salmonella sp., E. coli(þve
strai,), Rhodococci, B. stearothermophilus) by measuring
the zone of inhibition on agar plates. The compounds
possess moderate to good activity against all strains in
comparison with standard drug (Table 2). It can be
observed from these results that compounds IIa–IIj
have shown positive bacterial activity against different
bacterial species, which are also known as human patho-
genic bacteria. It was also observed that within the syn-
thesized compound extracts, highest zone of inhibition
recorded in 3-chloro-4-(furan-2-yl)-1-(4-(phenyl dia-
zenyl) phenyl)azetidin-2-one (IIe) extract against the P.
vulageris 22 mm, which is more than standard, i.e., 17
mm zone of inhibition.
of Ia–Ij with ketene, which is generated in situ from
chloroacetic acid in presence of trimethylamine and
POCl3 (Scheme 1). The Schiff bases were also prepared
by using microwave method [24].
However, the synthesis of Schiff bases Ia–Ij under
the classical reaction was plagued by a number of seri-
ous disadvantages such as low yield of the product as
given in Table 1. Therefore, to overcome the drawbacks
of the classical method, modern version of this reaction
by microwave superheating in solvent and solvent free
condition has been adopted. All the synthesized com-
pounds were characterized on the basis of different
spectral analysis techniques such as IR and 1H NMR
and elemental analysis techniques. Also in the present
communication, we report the antibacterial activities of
the titled compounds (IIa–IIj) against nine different
bacterial strains.
Scheme 1. Synthesis of Schiff base with different synthetic path and 3-chloro-4-aryl-1-(4-(phenyldiazenyl)phenyl)azetidin-2-one.
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
An Efficient Synthesis and Biological Testing of Novel
3-Chloro-4-aryl-1-(4-(phenyldiazenyl)phenyl)azetidin-2-ones
1363
Table 1
Time and yield comparison between classical and MW irradiation.
Reaction time (min/sec)
Yield (%)a
MWI, Solvent
Free
Classical,
EtOH
MWI,
Solvent Free
Classical,
EtOH
Compound
Ar
MWI, EtOH
MWI, EtOH
Ia
Ib
Ic
Id
Ie
If
Ig
Ih
Ii
C6H5
2-OHC6H4
2-NO2C6H4
3-NO2C6H4
C4H3O
4-OHC6H4
4-N(CH3)2C6H4
2-ClC6H4
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
1 min 20 sec
150 min
150 min
150 min
150 min
150 min
150 min
150 min
150 min
150 min
150 min
92
90
87
95
90
85
92
95
97
88
90
85
82
92
85
80
87
88
95
80
85
80
75
85
70
65
80
75
85
60
3-BrC6H4
4-ClC6H4
Ij
a Isolated yields.
EXPERIMENTAL
reaction mixture was irradiated for 1min 20 sec with 100 W
microwaves at 110ꢀC in MW oven in the temperature control
mode. The completion of the reaction was monitored by TLC.
The crude product was recrystallized with methanol.
Microwave method with solvent. Equimolar amount of p-
aminoazobenzene (0.001 mol) and aromatic aldehyde (0.001
mol) and ethanol were taken in a glass tube which was loosely
closed and irradiated in MW oven for 1min 20 sec. The com-
pletion of the reaction was monitored by TLC. The reaction
mixture was allowed to attain room temperature. The solvent
was removed, and the crude product was recrystallized with
methanol.
Classical method. Equimolar amount of p-aminoazoben-
zene (0.001 mol), aromatic aldehyde (0.001 mol), and 10
mL of ethanol was refluxed for 2 hr 30 min. The reaction
was monitored by TLC. After completion of the reaction,
the reaction mixture was set on one side to cool. Then, the
reaction mixture was poured in ice cold water and the solid
precipitate was separated out. The precipitate was filtered
and collected crude product was recrystallized using
methanol.
General. All the chemicals and solvents were obtained
from E-Merck, India (AR grade) and were used without further
purification. Melting points were taken in an open capillary
tube. The microwave assisted synthesis of Schiff base com-
pounds were carried out in a CEM–908010, bench mate
model, 300 watts laboratory microwave reactor. IR spectra
were recorded on a Shimadzu Dr-8031 instrument. Elemental
analyses were carried out using a Perkin-Elmer, CHN elemen-
tal analyzer model 2400. 1H NMR spectra of the synthesized
compounds were recorded on a Bruker-Avance (300 MHz) and
Varian-Gemini (200 MHz) spectrophotometer using CDCl3
solvent and TMS as an the internal standard. EI-MS spectra
were determined on a LCQ ion trap mass spectrometer
(Thermo Fisher, San Jose, CA, USA), equipped with an EI
source.
Synthesis of Schiff base (Ia–Ij).
Microwave method
without solvent. Equimolar amount of p-aminoazo benzene
(0.001 mol) and aromatic aldehyde (0.001 mol) were thor-
oughly mixed in a glass tube, which was loosely closed. The
Table 2
Biological activities of compounds chloro-4-(aryl)-1-(4-(phenyldiazenyl) phenyl)azetidin-2-one (IIa–IIj).
Zone of inhibition in mm along without well diameter (5 mm)
Chemical compounds
Standard
Nystatin
Bacterial strain
IIa
IIb
IIc
IId
IIe
IIf
IIg
IIh
IIi
IIj
E. coil (mixed)
B. subtilis
20
3
16
5
6
2
12
–
–
3
7
2
14
8
9
6
13
9
16
2
17
6
Pseudomonas sp.
S. aureus
P. vulageris
Salmonella sp.
E. coil(þve strain)
Rhodococci
13
–
3
–
15
4
6
7
10
5
6
5
8
10
4
13
8
9
6
12
9
10
16
10
10
5
15
9
11
15
–
9
13
6
13
20
4
22
17
9
8
8
14
16
7
10
14
–
2
10
5
15
2
17
19.1
11
6
–
–
13
3
–
–
4
2
3
1
B. stearothermopelus
5
2
4
6
2
5
3
4
6
7.2
‘‘–’’ represent ‘‘not active.’’
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

1364
H. N. Chopde, R. Pagadala, J. S. Meshram, and V. Jetti
Vol 47
N-Benzylidene-4-(phenyldiazenyl)aniline (Ia). m. p.: 150ꢀC,
NMR: d ¼ 6.60–7.30 (t, J ¼ 7.2 Hz, 3H, Ar-CH); 7.41 (s, 1H,
Ar-CH); 7.25–7.80(m, 7H, Ar-CH); 8.20 (d, J ¼ 8.8 Hz, 2H,
Ar-CH); 8.70(s, 1H, AN¼¼CH); Anal. Calcd.For C19H14N3Br:
C, 62.65; H, 3.87; N, 11.54; Found: C, 62.50; H, 3.60; N,
11.30; Mass spectra, m/z ¼ 363.50 (100%).
1
IR (KBr): 1410 cmꢁ1 (N¼¼N), 1620.2 (AC¼¼NA); H NMR: d
¼ 6.80 (d, J ¼ 8.4 Hz, 2H, Ar-CH); 7.20 (s, 1H, Ar-CH);
7.50–7.70 (m, 7H, Ar-CH); 7.80 (d, J ¼ 8.7 Hz, 2H, Ar-CH);
8.00 (d, J ¼ 8.2 Hz, 2H, Ar-CH); 8.60 (s, 1H, N¼¼CH); Anal.
Calcd. For C19H15N3 : C, 79.98; H, 5.30; N, 14.73; Found: C,
79.50; H, 5.00; N, 14.50; Mass spectra, m/z ¼ 285 (100%).
2-((4-(Phenyldiazenyl)phenylimino)methyl)phenol (Ib). m.
N-(4-Chlorobenzylidene)-4-(phenyldiazenyl)aniline (Ij). m.
1
p.: 190ꢀC, IR (KBr): 1470 cmꢁ1 (N¼¼N), 1660 (AC¼¼NA); H
NMR: d ¼ 6.80–7.45 (m, 4H, Ar-CH); 7.25–7.80(m, 7H,
Ar-CH); 8.30 (d, J ¼ 8.6 Hz, 2H, Ar-CH); 8.50(s, 1H,
AN¼¼CH); Anal. Calcd.For C19H14N3Cl: C, 71.36; H, 4.41; N,
13.14; Found: C, 71.20; H, 4.30; N, 12.90; Mass spectra, m/z
¼ 319 (100%).
1
p.: 165ꢀC, IR (KBr): 1430 cmꢁ1 (N¼¼N), 1600 (AC¼¼NA); H
NMR: d ¼ 6.70 (d, J ¼ 8.8 Hz, 2H, Ar-CH); 7.0–7.60 (m, 9H,
Ar-CH); 7.90 (d, J ¼ 8.9 Hz, 2H, Ar-CH); 8.35 (s, 1H,
AN¼¼CH); 11.20 (s, 1H, Ar-OH); Anal. Calcd. For
C19H15ON3: C, 75.73; H, 5.02; N, 13.94; Found: C, 75.50; H,
5.00; N, 13.60; Mass spectra, m/z ¼ 301 (100%).
General procedure for the preparation of 3-chloro-4-
aryl-1-(4-(phenyldiazenyl) phenyl) azetidin-2-one (IIa-
IIj). A mixture of Schiff base Ia–Ij (0.002 moles) and chloro-
acetic acid (0.002 moles) was dissolved in dichloromethane
(10 mL) in stoppered conical flask, cooled, and stirred. In cold
condition of the reaction mixture, triethylamine [TEA] (0.002
moles) was added in it, followed by dropwise addition of
POCl3 in dichloromethane (0.002 moles) with vigorous stir-
ring. The reaction mixture was then stirred for additional 16
hr. The completion of the reaction was monitored by TLC.
The reaction mixture was washed with water and dried over
sodium sulphate. The products that were obtained after remov-
ing the solvent were purified from chloroform.
N-(2-Nitrobenzylidene)-4-(pꢁh1enyldiazenyl)aniline (Ic). m.
1
p.: 160ꢀC, IR (KBr): 1420 cm (N¼¼N), 1610 (AC¼¼NA); H
NMR: d ¼ 6.50 (d, J ¼ 8.1 Hz, 2H, Ar-CH); 7.20 (s, 1H, Ar-
CH); 7.50–7.70 (m, 5H, Ar-CH); 7.80–8.00 (t, J ¼ 7.9 Hz,
3H, Ar-CH); 8.20 (d, J ¼ 8.8 Hz, 2H, Ar-CH); 8.64 (s, 1H,
AN¼¼CH); Anal. Calcd. For C19H14N4O2: C, 69.68; H, 4.27;
N, 16.96; Found: C, 69.40; H, 4.10; N, 16.60; Mass spectra,
m/z ¼ 330.11 (100%).
N-(3-Nitrobenzylidene)-4-(pꢁh1enyldiazenyl)aniline (Id). m.
1
p.: 175ꢀC, IR (KBr): 1430 cm (N¼¼N), 1650 (AC¼¼NA); H
NMR: d ¼ 6.80 (d, J ¼ 8.7 Hz,2H, Ar-CH); 7.20–8.30 (m,
10H, Ar-CH); 8.50 (s, 1H, Ar-CH); 8.60 (s, 1H, AN¼¼CH);
Anal. Calcd. For C19H14N4O2: C, 69.68; H, 4.27; N, 16.96;
Found: C, 69.20; H, 4.00; N, 16.20 ; Mass spectra, m/z ¼ 330
(100%).
3-Chloro-4-phenyl-1-(4-(phenyldiazenyl)phenyl)azetidin-2-one
(IIa). Yield: 80%; m. p.: 210ꢀC; IR (KBr, cmꢁ1): 1364
(CAN); 1460 (N¼¼N); 1760 (C¼¼O b-lactam); 1H NMR (300
MHz, CDCl3) d (ppm) ¼ 5.10 (s, 1H, ANACH), 5.40 (s, 1H,
ACHAC¼¼O), 6.80 (m, 4H, Ar-H); 7.25–7.40 (m, 6H, Ar-H);
7.60 (d, J ¼ 8.4 Hz, 2H, Ar-H); 8.00 (d, J ¼ 8.3 Hz, 2H, Ar-
H). Anal. Calcd. for C21H16N3OCl: C, 69.61; H, 4.41; N,
11.60; Found C, 69.50; H, 4.20; N, 11.40; Mass spectra, m/z
¼ 361 (100%).
N-(Furan-2-ylmethylene)-4-(phenyldiazenyl)aniline (Ie). m.
1
p.: 180ꢀC, IR (KBr): 1460 cmꢁ1 (N¼¼N), 1630 (AC¼¼NA); H
NMR: d ¼ 6.50 (s, 1H, Ar-CH); 6.85 (d, J ¼ 8.8 Hz, 2H, Ar-
CH); 6.90 (s, 1H, Ar-CH); 7.20 (s, 1H, Ar-CH), 7.50 (s, 1H,
AN¼¼CH); 7.55–7.65 (m, 4H, Ar-CH); 7.70 (s, 1H, Ar-CH);
8.00 (d,
J
¼
8.6 Hz, 2H, Ar-CH); Anal. Calcd. For
3-Chloro-4-(2-hydroxyphenyl)-1-(4-(phenyldiazenyl)phe-nyl)
azetidin-2-one (IIb). Yield: 91%; m. p.: 220ꢀC; IR (KBr,
cmꢁ1): 2973 (OH), 1360 (CAN); 1567 (N¼¼N); 1765 (C¼¼O
C17H13ON3: C, 74.17; H, 4.76; N, 15.26; Found: C, 74.00; H,
4.50; N, 15.00; Mass spectra, m/z ¼ 275 (100%).
b-lactam); 1H NMR (CDCl3): d(ppm)
¼
5.16 (s, 1H,
4-((4-(Phenyldiazenyl)phenylimino)methyl)phenol (If). m.
p.: 155ꢀC, IR (KBr): 1450 cmꢁ1 (N¼¼N), 1640 (AC¼¼NA); H
1
ANACH), 5.35 (s, 1H, ACHAC¼¼O), 6.80–6.95 (m, 4H, Ar-
H); 7.20 (s, 1H, Ar-H); 7.65 (t, J ¼ 7.2 Hz, 3H, Ar-H); 7.90
(d, J ¼ 8.1 Hz, 2H, Ar-H); 8.30 (t, J ¼ 7.3 Hz, 3H, Ar-H);
9.50 (s, 1H, Ar-OH). Anal. Calcd. for C21H16O2N3Cl: C,
66.66; H, 4.23; N, 11.11; Found: C, 66.40; H, 4.10; N, 11.00;
Mass spectra, m/z ¼ 377 (100%).
NMR: d ¼ 6.85 (m, 4H, Ar-CH); 7.20 (s, 1H, Ar-CH); 7.55–
7.60 (m, 4H, Ar-CH); 7.75–7.80 (d, J ¼ 8.4 Hz, 2H, Ar-CH),
8.00 (d, J ¼ 8.7 Hz, 2H, Ar-CH); 8.50 (s, 1H, AN¼¼CH); 9.40
(s, 1H, Ar-OH); Anal. Calcd. For C19H15N3O: C, 75.73; H,
5.02; N, 13.94; Found: C, 75.00; H, 4.90; N, 13.40; Mass
spectra, m/z ¼ 301.20 (100%).
3-Chloro-4-(2-nitrophenyl)-1-(4-(phenyldiazenyl)phenyl)
azetidin-2-one (IIc). Yield: 95%; m. p.: 225ꢀC; IR (KBr,
N,N-dimethyl-4-((4-phenyldiazenyl)phenylimino) methyl)a-
niline (Ig). m. p.: 180ꢀC, IR (KBr): 1400 cmꢁ1 (N¼¼N), 1620
(AC¼¼NA); 1H NMR: d ¼ 3.00 (s, 6H, AN(CH3)2); 6.80–
6.85 (m, 4H, Ar-CH); 7.20 (s, 1H, Ar-CH); 7.50 (d, J ¼ 8.6
Hz, 2H, Ar-CH); 7.60–7.68 (m, 4H, Ar-CH), 7.90 (d, J ¼ 8.7
Hz, 2H, Ar-CH); 8.55 (s, 1H, AN¼¼CH); Anal. Calcd. For
C21H20N4: C, 76.80; H, 6.14; N, 17.06; Found: C, 76.40; H,
6.00; N, 17.00; Mass spectra, m/z ¼ 328 (100%).
cmꢁ1): 1340 (CAN); 1580 (N¼¼N); 1755 (C¼¼O b-lactam); H
1
NMR (CDCl3): d(ppm) ¼ 5.00 (s, 1H, ANACH), 5.30 (s, 1H,
ACHAC¼¼O), 6.90 (m, 4H, Ar-H); 7.10 (s, 1H, Ar-H); 7.40
(d, J ¼ 8.1 Hz, 2H, Ar-H); 7.60 (d, J ¼ 8.4 Hz, 2H, Ar-H);
7.70 (d, J ¼ 8.1 Hz, 2H, Ar-H); 8.00 (t, J ¼ 7.6 Hz, 3H, Ar-
H); 8.30 (t, J ¼ 7.4 Hz, 3H, Ar-H). Anal. Calcd. for
C21H19N4O3Cl: C, 61.91; H, 3.68; N, 13.75; Found: C, 61.00.;
H, 3.60; N, 13.60; Mass spectra, m/z ¼ 406 (100%).
N-(2-Chlorobenzylidene)-4-(phenyldiazenyl)aniline (Ih). m.
p.: 195ꢀC, IR (KBr): 1420 cmꢁ1 (N¼¼N), 1630 (AC¼¼NA); H
1
3-Chloro-4-(3-nitrophenyl)-1-(4-(phenyldiazenyl)phenyl)
azetidin-2-one (IId). Yield: 90%; m. p.: 205ꢀC; IR (KBr,
NMR: d ¼ 6.80–7.50 (m, 4H, Ar-CH); 7.20–7.60(m, 7H, Ar-
CH); 8.00 (d, J ¼ 8.5 Hz, 2H, Ar-CH); 8.30(s, 1H, AN¼¼CH);
Anal. Calcd.For C19H14N3Cl: C, 71.36; H, 4.41; N, 13.14; Found:
C, 71.00; H, 4.20; N, 13.00; Mass spectra, m/z ¼ 319 (100%).
N-(3-Bromobenzylidene)-4-(phenyldiazenyl)aniline (Ii). m.
cmꢁ1): 1330 (CAN); 1590 (N¼¼N); 1740 (C¼¼O b-lactam); H
1
NMR (CDCl3): d (ppm) ¼ 5.10 (s, 1H, ANACH), 5.40 (s, 1H,
ACHAC¼¼O), 6.70 (d, J ¼ 8.5 Hz, 2H, Ar-H); 7.20 (s, 1H,
Ar-H); 7.60–7.68 (m, 4H, Ar-H); 8.00–8.08 (t, J ¼ 7.1 Hz,
3H, Ar-H); 8.18 (s, 1H, Ar-H); 8.20 (d, J ¼ 8.4 Hz, 2H, Ar-
p.: 170ꢀC, IR (KBr): 1440 cmꢁ1 (N¼¼N), 1650 (AC¼¼NA); H
1
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

November 2010
An Efficient Synthesis and Biological Testing of Novel
3-Chloro-4-aryl-1-(4-(phenyldiazenyl)phenyl)azetidin-2-ones
1365
H). Anal. Calcd. for C21H15N4O3Cl: C, 61.91; H, 3.68; N,
13.75; Found: C, 61.20; H, 3.40; N, 13.50; Mass spectra, m/z
¼ 405.9 (100%).
10.60; Found: C, 63.40; H, 3.50; N, 10.30; Mass spectra,
m/z ¼ 395 (100%).
3-chloro-4-(furan-2-yl)-1-(4-(phenyldiazenyl)phenyl)az-eti-
din-2-one (IIe). Yield: 85%; m.p.: 225ꢀC; IR (KBr, cmꢁ1):
1310 (CAN); 1560 (N¼¼N); 1710 (C¼¼O b-lactam); 1H NMR
(CDCl3): d(ppm) ¼ 5.35 (s, 1H, ANACH), 5.45 (s, 1H,
ACHAC¼¼O), 6.40–6.45 (t, J ¼ 7.4 Hz, 3H, Ar-H); 6.80 (s,
1H, Ar-H); 7.10 (d, J ¼ 8.1 Hz, 2H, Ar-H); 7.60 (d, J ¼ 8.3
Hz, 2H, Ar-H); 7.70 (d, J ¼ 8.2 Hz, 2H, Ar-H); 8.10 (d, J ¼
8.3 Hz, 2H, Ar-H). Anal. Calcd. for C19H14O2N3Cl: C, 64.77;
H, 3.97; N, 11.93; Found: C, 64.60; H, 3.80; N, 11.80; Mass
spectra, m/z ¼ 351 (100%).
CONCLUSIONS
A new method for the synthesis of Schiff base Ia–Ij
using microwave irradiation offers significant improve-
ments over existing procedures. Also, this simple and
reproducible technique affords the products with short
reaction times, excellent yields, and without formation
of undesirable side products. From data of antimicrobial
activity, it could be observed that compounds of the
series IIa–IIj showing good comparable activity against
standard drugs.
3-chloro-4-(4-hydroxyphenyl)-1-(4-(phenyldiazenyl) phenyl)
azetidin-2-one (IIf) Yield: 75%; m. p.: 230ꢀC; IR (KBr,
1
cmꢁ1): 1345 (CAN); 1600 (N¼¼N); 1755 (C¼¼O b-lactam); H
NMR (CDCl3): d(ppm) ¼ 5.00 (s, 1H, ANACH), 5.40 (s, 1H,
ACHAC¼¼O), 6.70–6.80 (m, 4H, Ar-H); 7.00 (d, J ¼ 8.4 Hz,
2H, Ar-H); 7.50 (d, J ¼ 8.6 Hz, 2H, Ar-H); 7.90 (t, J ¼ 7.6
Hz, 3H, Ar-H); 8.20 (d, J ¼ 8.4 Hz, 2H, Ar-H); 9.30 (s, 1H,
Ar-OH). Anal. Calcd. for C21H16N3O2Cl: C, 66.66; H, 4.23;
N, 11.11; Found : C, 66.30; H, 4.20; N, 11.10 ; Mass spectra,
m/z ¼ 377 (100%).
Acknowledgment. The authors greatly acknowledge Head
of the Chemistry Department RTM Nagpur University, for
laboratory facilities.
REFERENCES AND NOTES
3-chloro-4-(4-(dimethylamino)phenyl)-1-(4-(phenyldiaz-enyl)
phenyl)azetidin-2-one (IIg). Yield: 95%; m. p.: 220ꢀC; IR
(KBr, cmꢁ1): 1335 (CAN); 1620 (N¼¼N); 1765 (C¼¼O b-lac-
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1
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(s, 1H, ANACH), 5.30 (s, 1H, ACHAC¼¼O), 6.70 (d, J ¼ 8.3
Hz, 2H, Ar-H); 6.80 (d, J ¼ 8.2 Hz, 2H, Ar-H); 7.10 (d, J ¼
8.2 Hz, 2H, Ar-H); 7.20 (s, 1H, Ar-H); 7.55 (d, J ¼ 8.5 Hz,
2H, Ar-H); 8.00 (d, J ¼ 8.4 Hz, 2H, Ar-H); 8.40 (d, J ¼ 8.2
Hz, 2H, Ar-H); Anal. Calcd. for C23H21ON4Cl: C, 68.14; H,
5.18; N, 13.82; Found: C, 68.10; H, 5.10; N, 13.60; Mass
spectra, m/z ¼ 404 (100%).
3-chloro-4-(2-chlorophenyl)-1-(4-(phenyldiazenyl) phenyl)-
azetidin-2-one (IIh). Yield: 80%; m. p.: 240ꢀC; IR (KBr,
1
cmꢁ1): 1355 (CAN); 1660 (N¼¼N); 1770 (C¼¼O b-lactam); H
NMR (CDCl3): d(ppm) ¼ 4.90 (s, 1H, ANACH), 5.20 (s, 1H,
ACHAC¼¼O), 6.60 (d, J ¼ 8.4 Hz, 2H, Ar-H); 7.20–7.30 (m,
4H, Ar-H); 7.60–7.75 (t, J ¼ 7.5 Hz, 3H, Ar-H); 7.80 (d, J ¼
8.1 Hz, 2H, Ar-H); 8.20 (d, J ¼ 8.3 Hz, 2H, Ar-H); Anal.
Calcd. for C21H15ON3Cl2: C, 63.63; H, 3.78, N, 10.60; Found:
C, 63.50; H, 3.60; N, 10.50; Mass spectra, m/z ¼ 395 (100%).
4-(3-bromophenyl)-3-chloro-1-(4-(phenyldiazenyl) phenyl)-
azetidin-2-one (IIi). Yield: 87%; m. p.: 245ꢀC; IR (KBr,
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1
cmꢁ1): 1365 (CAN); 1630 (N¼¼N); 1740 (C¼¼O b-lactam); H
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NMR (CDCl3): d(ppm) ¼ 5.10 (s, 1H, ANACH), 5.30 (s, 1H,
ACHAC¼¼O), 6.70 (d, J ¼ 8.3 Hz, 2H, Ar-H); 7.20–7.30 (t,
J ¼ 7.6 Hz, 3H, Ar-H); 7.40–7.45 (d, J ¼ 8.6 Hz, 2H, Ar-H);
7.60 (d, J ¼ 8.4 Hz, 2H, Ar-H); 7.90 (d, J ¼ 8.4 Hz, 2H, Ar-
H); 8.40 (d, J ¼ 8.5 Hz, 2H, Ar-H); Anal. Calcd. for
C21H15ON3BrCl: C, 57.14; H, 3.40; N, 9.52; Found: C, 57.10;
H, 3.30; N, 9.40; Mass spectra, m/z ¼ 439 (100%).
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1
cmꢁ1): 1370 (CAN); 1650 (N¼¼N); 1720 (C¼¼O b-lactam); H
NMR (CDCl3): d(ppm) ¼ 5.00 (s, 1H, ANACH), 5.40 (s, 1H,
ACHAC¼¼O), 6.90 (d, J ¼ 8.4 Hz, 2H, Ar-H); 7.20 (s, 1H,
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