Synthesis of benzoxazepine derivatives from pyrazole-chalcone via a simple and convenient protocol using basic alumina as solid support

Article abstract of DOI:10.4067/s0717-97072018000203983

In the present study a series of novel benzoxazepine (5a-h) derivatives were synthesized by the thermal cyclization reaction of various pyrazole-chalcones (3a-h) with 2-aminophenol, by conventional heating and microwave irradiation (180 W) in solvent-free conditions in short reaction times (9-12 min), giving high yields of products (80-88%). The homogeneity of all the newly synthesized compounds has been checked by TLC. Their IR, NMR, ESI-mass spectral data and elemental analysis are in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against Gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, and Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli. Compounds 3c, 3h, 5b, 5c, 5g and 5h were found to show good antibacterial activity when compared with that of standard drug Ampicillin. Furthermore, the same library of compounds were evaluated for antifungal activity against Aspergillus nigerzeae, Penicillium italicum and Fusarium oxysporum using Grieseofulvin as standard drug. The results of the above studies show that the compounds 3b, 3c, 3e, 3h, 5a, 5c, 5g and 5h showed good antifungal activity against all the tested organisms.

Full text of DOI:10.4067/s0717-97072018000203983

J. Chil. Chem. Soc., 63, Nº 2 (2018)
SYNTHESIS OF BENZOXAZEPINE DERIVATIVES FROM PYRAZOLE-CHALCONE VIA A SIMPLE AND
CONVENIENT PROTOCOL USING BASIC ALUMINA AS SOLID SUPPORT
D. ASHOK*1, G. RADHIKA1, BODDU ANANDA RAO1, M. SARASIJA1,
A. JAYASHREE2 AND P. SADANANDAM2
1Green and Medicinal Chemistry Laboratory, Department of Chemistry, Osmania University, Hyderabad, 500007, India.
2Centre for Chemical Sciences & Technology, JNTU-H, Hyderabad, 500085, India.
ABSTRACT
In the present study a series of novel benzoxazepine (5a-h) derivatives were synthesized by the thermal cyclization reaction of various pyrazole-chalcones
(3a-h) with 2-aminophenol, by conventional heating and microwave irradiation (180 W) in solvent-free conditions in short reaction times (9–12 min), giving high
yields of products (80–88%). The homogeneity of all the newly synthesized compounds has been checked by TLC. Their IR, NMR, ESI-mass spectral data and
elemental analysis are in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against Gram-positive bacteria
Staphylococcus aureus, Bacillus subtilis, and Gram-negative bacteria Pseudomonas aeruginosa, Escherichia coli. Compounds 3c, 3h, 5b, 5c, 5g and 5h were
found to show good antibacterial activity when compared with that of standard drug Ampicillin. Furthermore, the same library of compounds were evaluated for
antifungal activity against Aspergillus nigerzeae, Penicillium italicum and Fusarium oxysporum using Grieseofulvin as standard drug. The results of the above
studies show that the compounds 3b, 3c, 3e, 3h, 5a, 5c, 5g and 5h showed good antifungal activity against all the tested organisms.
Keywords: Pyrazole, Chalcone, benzoxazepine, microwave irradiation, basic alumina.
reactions the products were achieved in high yield. Chemical structures of
compounds were confirmed by IR, 1H NMR, 13C NMR, ESI-MS, spectral data
and elemental analysis.
INTRODUCTION
The prominence in attaining chalcones has numerous applications in the
field of pharmaceutics and also in the production of pesticides, cosmetics1,2.
Chalcone and its functionalized derivatives display diverse pharmacological
EXPERIMENTAL
properties have been discovered as, antimicrobial3-8
, ,
antitubercular3,9,10
anticancer10,11, anti-inflammatory10, and antioxidant7 activities. Chalcones
bear very good synthon framework so that variety of novel heterocycles with
good pharmaceutical profile can be designed. On the other hand, pyrazoles
represent a key motif in heterocyclic chemistry and occupy a prime place in
medicine and pesticide chemistry due to their capability to exhibit a wide
range of bioactivities such as antimicrobial, anti-inflammatory, anticancer and
antiviral12-15. Pyrazoles were found to possess inhibitory activities against XO,
cyclooxygenase, and alkaline phosphatases16, 17. Benzoxazepine derivatives
are prevalent designs of biologically active compounds18,19. These derivatives
are well-known pharmacophores showing capable properties against various
diseases such as antipsychotic20, central nervous system damage21 and anticancer
activities22. Usually, benzoxazepine derivatives preparation involves multistep
synthesis23-25. Therefore, an efficient, eco-friendly, straightforward synthetic
method toward benzoxazepine still represents an interesting assignment for
chemists.
The science of green chemistry was developed to chance the increasing
demand for environmentally gentle chemical practices. Solvent free synthesis
has received considerable attention in recent years. Microwave heating
has a prominence in the search for green synthesis26. Microwave irradiation
conditions extensively reduce reaction time without promoting any side
reactions27,28. Alumina like solid support, holds excellent capability to absorb
the organic compounds on their surface, and transmits microwave irradiation.
Previous reports have also shown that the basic oxides, like alumina, assist as
a good alternative for catalyzed heteroannulation reactions due to its character
as a base ion in the solid framework29. This provoked us to discover an efficient
yet simple and one-pot green protocol using basic alumina as solid support in
microwave irradiation.
All the melting points were determined in open capillary tubes and are
uncorrected. The purity of the compounds was checked by TLC on silica gel
60 F254 (Merck). 1H NMR and 13C NMR spectra were recorded on Avance 400
spectrometer using CDCl solvent TMS as an internal standard. IR spectra were
recorded in KBr Shimadz3u FTIR 8400 S spectrophotometer. Mass spectra were
recorded on LCMS-2010A Shimadzu spectrophotometer. Elemental analysis
was determined by using the EA1112 Thermofinnigan CHNS analyzer.
Microwave reactions were carried out in a Multisynth series microwave system
(Milestone).
Conventional heating method (A)
A mixture of chalcone (3a-h) [30] (0.01mol), 2-amino phenol (7) (0.01
mol) were dissolved in 10 ml of ethanol and to this K2CO3 (2 g) was added.
The contents were refluxed for appropriate time mentioned in Table-1. The
progress of the reaction was monitored by TLC. After completion of the
reaction, the mixture was cooled to room temperature and poured into water.
The product was extracted with acetone and was recrystalized with acetone to
afford pure compounds (5a-h).
Microwave irradiation method (B)
A mixture of chalcone (3a-h) (0.01mol), 2-amino phenol (7) (0.01 mol)
was adsorbed on basic alumina (3 g). The adsorbed material was taken in
a quartz tube and inserted into the Teflon vial with screw capped and then
subjected to microwave irradiation for an appropriate given time in Table-1.
After completion of the reaction, cooled to room temperature and the product
was extracted with acetone and was recrystalized with acetone to afford pure
compounds (5a-h).
2-((E)-2,3-dihydro-2-(1,3-diphenyl-1H-pyrazol-4-yl)benzo[b][1,4]
oxazepin-4-yl)phenol (5a)
In the current study, we aimed to obtain new compounds containing
both pyrazole and benzoxazepine rings in the same structure, via the cyclo-
condensation reaction, solvent free microwave irradiation conditions. This non-
conventional protocol offers several applications such as simple procedure, fast
reaction conditions and good yields as compared to conventional methods. It
involves the exposure of neat reactants to give high yields of pure products,
easy work-up, low cost and economical. The use of basic alumina as a solid
support assists and it eliminates the use of K2CO and ethanol solvent. Herein,
we have shown (Scheme 1) the synthesis of3 benzoxazepines derivatives
from pyrazole-chalcone reaction with 2-amino phenol, basic alumina as a
solid support using as a catalyst under microwave irradiation (180 W). In all
White solid; IR spectrum, ν cm−1: 3135 (OH), 1607 (C=N), 1238 (C-O-C).
1HNMR spectrum, δ, ppm: 8,.12 (s, 1H, pyrazole-H), 7.98-6.99 (m, 18H,
Ar-H), 5.67 (dd, 1H, JXB=12.4HZ, JXA=3.2HZ), 3.24 (dd, 1H, JBA=16.8HZ,
J
=12.4HZ), 3.04 (dd, 1H, J =16.8HZ, JAX=3.2HZ). 13СNMR spectrum, δС,
pBpXm: 154.5, 152.1, 147.3, 139.A8B, 133, 129.5, 128.7, 128.6, 128.3, 128.2, 126.7,
126.1, 125.7, 124.9, 124.7, 124, 123.2, 120.3, 119.5, 119.2, 112.5, 70, 42.5.
Found, %: C 78.71; H 5.04; N 9.23. C30H23N3O2. Calculated, %: C 78.75; H
5.07; N 9.18. MS: 458 [M+H]+.
3983
e-mail: ashokdou@gmail.com

J. Chil. Chem. Soc., 63, Nº 2 (2018)
Table 1: Conventional heating and Microwave irradiation optimization for the synthesis of 5a-h.
Conventional heating (A)
Microwave irradiation (B)
Compound
Number
Molecular Formula
(Mol. Wt)
M.P. (°C)
Time (h)
Yield (%)
Time (min)
Yield (%)
5a
5b
5c
5d
5e
5f
C30H23N3O2 (457)
C31H25N3O2 (471)
C31H25N3O3 (487)
C30H22ClN3O2 (491)
C30H22BrN3O2 (535)
C30H22BrN3O2 (535)
C31H24BrN3O2 (549)
C31H24BrN3O3 (565)
180-182
193-195
188-190
176-178
222-224
254-256
226-268
252-254
6
8
8
8
9
9
7
8
60
62
70
68
65
62
60
62
9
10
10
12
9
85
83
85
80
88
85
80
82
9
5g
5h
10
9
2-((E)-2,3-dihydro-2-(1-phenyl-3-p-tolyl-1H-pyrazol-4-yl)benzo[b][1,4]
oxazepin-4-yl)phenol (5b)
3.01 (dd, 1H, JAB=16.8 HZ, JAX=2.8 HZ), 2.41 (s, 3H, CH3). 13СNMR spectrum,
δ , ppm: 161.4, 152.2, 140.3, 138.4, 136.1, 129.5, 129.4, 128.5, 127.3, 126.8,
1С21.8, 121.6, 119.7, 119.6, 119.3, 118.2, 72.4, 43.8, 21.8. Found, %: C 78.93,
H 5.32, N 8.94. C31H25N3O2. Calculated, %: C 78.96; H 5.34; N 8.91. MS: 472
[M+H]+.
White solid; IR spectrum, ν, cm−1: 3141 (OH), 1611 (C=N), 1231 (C-O-C).
1HNMR spectrum, δ, ppm: 8.13 (s, 1H, pyrazole-H ), 7.98-7.07 (m,17H, Ar-H),
5.67 (dd, 1H, JXB=12.4HZ, JXA=2.8HZ), 3.22 (dd, 1H, JBA=16.8HZ, JBX=12.4HZ),
Scheme 1: Synthesis of pyrazole-chalcones (3a-h) and benzoxazepines (5a-h)
2-((E)-2,3-dihydro-2-(3-(4-methoxyphenyl)-1-phenyl-1H-pyrazol-4-yl)
benzo[b][1,4]oxazepin-4-yl)phenol (5c)
2-((E)-2-(3-(4-chlorophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,3-
dihydrobenzo[b][1,4]oxazepin-4-yl) phenol (5d)
White solid; IR spectrum, ν, cm−1: 3142 (OH), 1600 (C=N), 1239 (C-O-C).
1HNMR spectrum, δ, ppm: 8.11 (s, 1H, pyrazole-H ), 7.98-6.98 (m,17H, Ar-
H), 5.65 (dd, 1H, JXB=12.4H , J =2.8HZ), 3.86 (s, 3H, OCH3), 3.23 (dd, 1H,
JBA=16.8HZ, JBX=12 HZ), 3.Z01 X(Add, 1H, JAB=16.8H JAX=2.8H ). 13СNMR
spectrum, δС, ppm: 163.7, 161.2, 160.1, 153.7, 151Z.8, , 140.1, 1Z35.9, 129.6,
129.3, 127.1, 126.6, 125.4, 121.6, 119.4, 119.2, 118, 114.3, 72.3, 55.3, 43.5,
29.5. Found, %: C 76.40, H 5.18, N 8.67. C31H25N3O3. Calculated, %: C 76.37;
H 5.17; N 8.62. MS: 488 [M+H]+.
White solid; IR spectrum, ν, cm−1: 3141 (OH), 1602 (C=N), 1229 (C-O-C).
1HNMR spectrum, δ, ppm: 8.13 (s, 1H, pyrazole-H), 7.99-7.06 (m, 17H, Ar-
H), 5.65 (dd, 1H, JXB=12HZ, JXA=3.2H ) 3.26 (dd, 1H, JBA=14.2, JBX=12HZ),
3.03 (dd, 1H, JAB=14.2HZ, JAX=3.2HZ).Z 13СNMR spectrum, δС, ppm: 160.9,
150.8, 139.8, 136.1, 134.6, 131.3, 129.6. 129.4, 128.8, 127,1, 126.9, 121.8,
121.2, 119.4, 119.3, 117.9, 71.9, 43.3. Found, %: C 73.21; H 4.48; N 8.57.
C30H22ClN3O2. Calculated, %: C 73.24; H 4.51; N 8.54. MS: 492 [M+H]+.
3984

J. Chil. Chem. Soc., 63, Nº 2 (2018)
2-((E)-2-(3-(4-bromophenyl)-1-phenyl-1H-pyrazol-4-yl)-2,3-
dihydrobenzo[b][1,4]oxazepin-4-yl) phenol (5e)
Table 2: Antibacterial activity of compounds 3a-h and 5a-h.
Zone of Inhibition, mm
Gram-positive bacteria Gram-negative bacteria
Staphylococcus Bacillus Pseudomonas Escherichia
White solid; IR spectrum, ν cm−1: 3140 (OH), 1604 (C=N), 1225 (C-O-C).
1HNMR spectrum, δ, ppm: 8,.13 (s, 1H, pyrazole-H), 7.99-7.05 (m, 17H,
Ar-H), 5.66 (dd, 1H, JXB =12.4HZ, JXA=3.2HZ), 3.23 (dd, 1H, JBA=16.8HZ,
Compound
J
=12.4HZ), 3.03 (dd, 1H, J =16.8HZ, JAX=3.2HZ). 13СNMR spectrum, δС,
pBpXm: 160.9, 150.9, 139.8, 136.A1B, 131.8, 129.9, 129.4, 127.1, 127, 122.7, 121.8,
121.2, 119.4, 119.3, 118, 71.9, 43.3, 29.6. Found, %: C 67.51; H 3.57; N 7.86.
C30H22BrN3O2. Calculated, %: C 67.17; H 4.13; N 7.83. MS: 535 [M]+, 537
[M+2]+.
aureus
23
24
30
22
12
10
22
28
22
27
28
20
18
15
28
32
30
subtilis
05
10
12
07
04
08
10
12
08
10
11
aeruginosa
coli
10
25
32
25
12
23
22
29
17
28
32
22
21
18
28
28
30
3a
04
08
09
08
03
02
07
11
05
08
08
05
08
06
09
10
10
3b
3c
4-bromo-2-((E)-2,3-dihydro-2-(1,3-diphenyl-1H-pyrazol-4-yl)benzo[b]
[1,4]oxazepin-4-yl)phenol (5f)
3d
White solid; IR spectrum, ν, cm−1: 3402 (OH), 1600 (C=N), 1238 (C-O-C).
1HNMR spectrum, δ, ppm: 8.09 (s, 1H, Pyrazole-H), 7.78-6.97 (m, 17H, Ar-
H), 5.64 (dd, 1H, J =12HZ, JXA=3.2HZ), 3.21 (dd, 1H, JBA=16.8HZ, JBX=12HZ),
3e
3f
3.02 (dd, 1H, JAB=X1B6.8H
J
=3.2HZ). 13СNMR spectrum, δС, ppm: 160, 158,
154.6, 151, 141.1, 130.4,Z1, 2A9X.4, 129.3, 127.5, 126.4, 125.8, 125.5, 122.3, 119,
116.7, 114.3, 70.1, 40.88. Found, %: C 67.14; H 4.11; N 7.86. C30H22BrN3O2.
Calculated, %: C 67.17; H 4.13; N 7.83. MS: 535 [M]+, 537 [M+2]+.
3g
3h
5a
4-bromo-2-((E)-2,3-dihydro-2-(1-phenyl-3-p-tolyl-1H-pyrazol-4-yl)
benzo[b][1,4]oxazepin-4-yl) phenol (5g)
5b
White solid; IR spectrum, ν, cm−1: 3137 (OH), 1602 (C=N), 1210 (C-O-C).
1HNMR spectrum, δ, ppm: 8.14 (s, 1H, Pyrazole-H), 7.81-6.98 (m, 16H, Ar-H),
5.64 (dd, 1H, JXB=12.4HZ, JXA=2.8H ), 3.21 (dd, 1H, JBA=16.8HZ, JBX=12.4HZ),
2.99(dd, 1H, JAB=16.8HZ, JAX=2.8HZ), 2.36 (s, 3H, CH3). 13СNMR spectrum,
δ , ppm: 159.2, 151.9, 140, 137.1, Z132.8, 131.2, 129.3, 128.5, 128.4, 128.3,
1С26.7, 126.6, 120.9, 119.7, 119.3, 117.8, 72.1, 43.6, 20.2. Found, %: C 67.61;
H 4.35; N 7.67. C31H24BrN3O2. Calculated, %: C 67.64; H 4.39; N 7.63. MS:
549 [M]+, 551 [M+2]+.
5c
5d
07
10
09
11
5e
5f
5g
5h
11
4-bromo-2-((E)-2,3-dihydro-2-(3-(4-methoxyphenyl)-1-phenyl-1H-
pyrazol-4-yl)benzo [b] [1,4] oxazepin-4-yl)phenol (5h)
Ampicillin
12
White solid; IR spectrum, ν, cm−1: 3135 (OH), 1598 (C=N), 1209 (C-O-C).
1HNMR spectrum, δ, ppm: 8.09 (s, 1H, Pyrazole-H) 8.08-6.93 (m, 16H, Ar-
H), 5.64 (dd, 1H, JXB=11.6HZ, J =3.2HZ), 3.86 (s, 3H, OCH3), 3.21 (dd, 1H,
JBA=16.8HZ, JBX=11.6HZ), 3.02X(Add, 1H, J =16.8HZ, JAX=3.2H ). 13СNMR
spectrum, δС, ppm: 152.96, 150.87, 147.5,A1B39.69, 134.33, 133Z.69, 131.58,
129.82, 129.53, 128.84, 126.91, 126.11, 125.05, 124.30, 122.67, 119.19,
112.85, 70.3, 43.4, 29.7. Found, %: C 65.70; H 4.25; N 7.46. C31H24BrN3O3.
Calculated, %: C 65.73; H 4.27; N 7.42. MS: 565 [M]+, 567 [M+2]+.
Antifungal activity
The antifungal activity of synthesized compounds 3a-h, 4a-h was tested
against three pathogenic fungi, namely Aspergillus niger, Penicillium italicum,
and Fusarium oxysporum, by the poison plate technique31 at a concentration
of 50 µg/mL. Three kinds of fungi were incubated in PDA at 25±1 °C for
5 days to get new mycelium for antifungal assay, then a mycelia as disks of
approximately 0.45 cm diameter cut from the culture medium were picked up
with a sterilized inoculation needle and inoculated in the center of PDA plate.
Test compounds were dissolved in acetone (10 mL) then added to the Potato
Dextrose Agar medium (PDA, 90 mL). The final concentration of compounds
in the medium was adjusted to 50 µg/mL. The inoculated plates were incubated
at 25±1 °C for 5 days. Acetone was diluted with sterilized distilled water and
used as control, while Grieseofulvin (50 µg/mL) was used as standard control
for each treatment three replicates of experiments were carried out. The radial
growth of the fungal colonies was measured on the sixth day. The Antifungal
activity was evaluated and the results are presented in Table 3.
BIOLOGICAL ASSAY
Antibacterial activity
The synthesized novel compounds 3a-h, 5a-g were screened for their
Antibacterial activity against different types of bacterial strains, they are Gram
positive bacterial strains of Bacillus subtilis and Staphylococcus aeureus,Gram
negative bacterial strains of Pseudomonas aeruginosa and Escherichia coli, at
a concentration of 50 µg/mL. The cultures were diluted with 5% autoclaved
saline and the final volume was made with concentration approximately
105-106 CFU/mL. The synthesized compounds were diluted in acetone for
antibacterial biological assays. For agar disc diffusion method30, the liquid
form of test compound was soaked on to the disc and then allowed to air dry,
such that the disc gets completely saturated with test compound. The saturated
chemical discs were introduced onto the upper layer of the medium evenly
loaded with the bacteria.
The discs were dipped in different chemical samples, were placed over
the evenly spread bacterial nutrient media and incubated at 37 oC for 24 to 48 h
for better inhibition of bacteria. The zones of inhibition were measured after 24
to 48 h. All the experiments were carried out in triplicates and the results were
expressed as zone of Inhibition in mm. The zones of inhibition of synthesized
compounds 3a-h, 5a-h were compared with the zone of inhibition of standard
antibiotic concentration of Ampicillin (50 µg/mL). The Antibacterial activity
was evaluated and the results are presented in Table 2.
RESULTS AND DISCUSSION
Chemistry
Several synthetic methodologies are available for the synthesis of
chalcones. Generally the condensation of acetophenone with aldehyde in
the presence of basic media is widely used. By keeping the view in green
methods we have selected to synthesize an efficient solvent free synthesis of
chalcones by grinding equimolar quantities of 2-hydroxy acetophenone and
substituted pyrazole aldehyde in the presence of Ba(OH)2, at room temperature
for 10 min. Further, these pyrazole-chalcones (3a-h)32,33 on thermal cyclization
with 2-aminophenol in the presence of basic alumina under microwave
irradiation34,35 resulted benzoxazepines (5a-h) in good yields (Scheme 1). All
the reactions were carried out using microwave irradiations in 9–12 min., while
same reactions under conventional condition, the time period required for the
completion of the reaction was quite long and gave moderate yields. Hence,
the microwave assisted synthesis bids clean and cheaper alternative path to that
of conventional heating, indicating that the microwave irradiation simplifies
the polarization of molecules producing reaction to occur at shorter reaction
times in good yields. The use of microwave irradiation in present investigation
gave 80–88% yields of product, whereas moderate yields were obtained by
conventional methods. All the synthesized compounds were characterized by
1H NMR, 13C NMR, Mass and IR spectral data.
3985

J. Chil. Chem. Soc., 63, Nº 2 (2018)
Table 3: Antifungal activity of Compounds 3a-h and 5a-h.
synthesized compounds, 3c, 3h, 5b, 5c, 5g and 5h showed good antibacterial
activity. The antifungal activity of the synthesized compounds also showed that
compounds 3b, 3c, 3e, 3h, 5a, 5c, 5g and 5h have good inhibition values. The
experimental results of this study will likely provide a new basis for the design
of interesting pyrazole-chalcones based benzoxazepine, and further studies,
including the design of new analogs of the heterocyclic moiety, are underway.
Zone of Inhibition, mm
Compound
Aspergillus
nigerzeae
Penicillium
italicum
Fusarium
oxysporum
3a
08
12
11
09
12
09
06
11
15
08
14
07
06
08
14
13
12
16
21
20
20
24
21
18
21
25
14
21
15
12
10
21
22
20
22
25
23
26
28
23
23
24
28
19
24
18
14
10
23
24
25
ACKNOWLEDGEMENTS
3b
The authors are grateful to Head, Department of Chemistry, Osmania
University, Hyderabad for providing laboratory facilities. Authors are also
thankful to DST, PURSE-II Programme, Osmania University for the Financial
assistance.
3c
3d
3e
3f
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3g
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Biological activities
Antibacterial activity
All the compounds were screened for their antibacterial activity against
Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa and
Escherichia coli using Ampicillin as standard drug. The activity was determined
using cup plate agar diffusion method by measuring the zone of inhibition in
mm (Table 2). The compounds were screened at the concentration of 50 μg/
ml in DMSO. From the screening studies it is evident that the synthesized
compounds 3c, 3h, 5b, 5c, 5g and 5h showed good antibacterial activity
against all the tested organisms, which shows that the electron releasing groups
enhanced the antibacterial activity. Furthermore, methoxy (3c), bromo methoxy
(3h), methyl (5b), methoxy (5c), bromo methyl (5g), and bromo methoxy (5h)
group derivatives are potentially active.
Antifungal activity:
All the compounds were screened for their antifungal activity against
Aspergillus nigerzeae, Penicillium italicum and Fusarium oxysporum using
Grieseofulvin as standard drug. The activity was determined using cup
plate agar diffusion method by measuring the zone of inhibition in mm. The
compounds were screened at the concentration of 50 μg/ml in DMSO. From
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organisms. However, in the case of the remaining compounds, the activity
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CONCLUSIONS
In summary, we have demonstrated an efficient, economical,
environmentally benign, and rapid process for the synthesis of benzoxazepines
derivatives from pyrazole-chalcones reaction with 2-amino phenol. It was
discovered that microwave-assisted method is highly efficient procedure for
the preparation of benzoxazepines, especially in the solvent-free media. This
method eliminates the use of K2CO and ethanol solvent. No additional base and
solventarerequiredasbasicalumina3 actsassolidsupportandbase. Additionally,
application of microwave decreases the time of the reaction extensively with
a better-quality yield of the product. The uniqueness of the methodology lies
in its eco-friendly operation, with excellent yield. In this study, a new hybrid
molecules consisting of biologically important benzoxazepine derivatives
(5a-h) from pyrazole-chalcones (3a-h) pharmacophores were synthesized
and their antibacterial and antifungal activities were determined. Amongst the
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