synthesis, characterization and antimicrobial screening of some
TRANSCRIPT
Research Journal of Chemical Sciences ______________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 20
Synthesis, Characterization and Antimicrobial screening of some Azo
compounds derived from Ethyl vanillin
Pagariya S.K.*, Pathade R.M. and Bodkhe P.S.
Department of Chemistry, Vidyabharati Mahavidyalaya, Amravati, 444602, INDIA
Available online at: www.isca.in, www.isca.me Received 19th June 2015, revised 30th June 2015, accepted 17th July 2015
Abstract
Azo compounds were synthesized in excellent yield by diazotization of some substituted aromatic amines using NaNO2 and
concentrated HCl followed by coupling with ethyl vanillin in alkaline medium. These azo compounds were characterized by
FTIR and H1
NMR spectroscopic technique and have been tested against the growth of five gram positive and negative
microorganisms in order to assess their antimicrobial activity.
Keywords: Azo compounds, ethyl vanillin, diazotization, antimicrobial activity.
Introduction
Azo compounds are mostly used as dyes due to its various
applications in the fields such as textile fibres, colouring of
different materials, biomedical studies and organic synthesis1-2
.
The azo dyes containing azo linkages have advanced
applications in high technology areas like lasers3, LCD color
filters4. In addition to this, azo dyes were reported to have
variety of biological applications like antineoplastics,
antidiabetics, antiseptics, anti-inflammatory and other useful
chemotherapeutic agents5-8
. Scarlet red and diamazon are the
most commonly used azo dyes which are antiseptics. Several
azo compounds derived from thymol9, aspirin
10, paracetamol
11,
m-cresol12
, resorcinol13
and vanillin14
moieties have been
frequently reported and exhibit excellent biological properties.
In the present work, we have synthesized four azo compounds
derived from ethyl vanillin and characterized by FTIR and H1
NMR spectral technique. The antimicrobial potential of
synthesized azo compounds of ethyl vanillin has been tested
against the growth of five gram positive and negative
microorganisms using agar well diffusion method.
Material and Methods
In the present synthesis, chemicals and reagents used were of
analytical grade, Merck and Alfa Aesar Company Ltd. The azo
compounds were characterized by FTIR and H1 NMR
spectroscopic techniques. The Perkin-Elmer spectrum One
FTIR instrument was used for characterization of IR spectra in
the form of KBr pallet. Bruker Avance II 400 MHz NMR
spectrometer was used for characterization of H1 NMR spectra
of azo compounds using CDCl3 as a solvent and TMS as an
internal standard. The purity of all the compounds was checked
by thin layer chromatography and were recrystalised from hot
ethanol. The melting points were measured by open capillary
method and they are uncorrected.
Procedure for the synthesis of azo compounds9-10:
Aromatic
amines (0.01 mole) were mixed with 2.5 ml of concentrated
HCl. To this resultant solution, 25 gm of crushed ice and 2.5 ml
of NaNO2 (4N) was added with constant stirring. The
temperature of the reaction mixture was kept constant up to 0-
50C. The diazonium salt solution prepared was added to the
alkaline solution of ethyl vanillin drop by drop with constant
stirring for 10-25 minutes at constant temperature of 5-100C.
The colored precipitate given out was filtered and washed with
water number of times. The colored product was recrystallised
from hot ethanol. The general reaction scheme for synthesis of
azo compounds of ethyl vanillin is shown in figure-1.
Antimicrobial Activity: The azo compounds 1a-d were
analysed for their antibacterial activity against five gram
positive and negative pathogens viz. Escherichia coli,
Pseudomonas aeroginosa, Salmonella typhi, Bacillus subtilis
and Staphylococcus aureus by using agar well diffusion
method15-16
. These compounds were mixed in DMSO to form
solutions of concentration 1mg/ml. Sterile discs were dipped in
this solutions, dried it and placed on nutrient agar plates
spreaded with the bacteria. The plates were further incubated for
24 to 48 hours at 370C and the diameters of zones of inhibition
were measured in millimeter.
Results and Discussion
The data of synthesized azo compounds of ethyl vanillin (i.e.
symbols, compounds name, molecular formulae, molecular
weights, melting points and percentage yield) are given in table-
1. The FTIR and H1 NMR spectroscopic data of synthesized azo
compounds are illustrated in table-2 and are shown in figure-6
to 13. A total four azo compounds of ethyl vanillin have been
synthesized, recrystalised and used separately to study its
antimicrobial activity against five gram positive and negative
microorganism’s viz. Escherichia coli, Pseudomonas
aeroginosa, Salmonella typhi, Bacillus subtilis and
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 21
Staphylococcus aureus. The data on antimicrobial activity of
azo compounds of ethyl vanillin 1a-d against five pathogens are
presented in table-3. From the results it was observed that the
azo compounds of ethyl vanillin have showed miraculous
antibacterial potential against all five pathogens. The compound
1a showed 10.4 and 9.6 mm zones of inhibition against the test
pathogens Escherichia coli and Staphylococcus aureus
respectively as shown in figure-2 and do not showed any
inhibitory action against Salmonella typhi, Pseudomonas
aeroginosa and Bacillus subtilis. The azo compound 1b showed
10.6, 12.7, 11.8 and 9.8 mm zones of inhibition against the test
pathogens Escherichia coli, Salmonella typhi, Bacillus subtilis
and Staphylococcus aureus respectively shown in figure-3 but
do not showed any inhibitory action against Pseudomonas
aeroginosa. The azo compound 1c showed 10.3, 13.1, 13.5 and
12.8 mm zones of inhibition against the pathogens Escherichia
coli, Salmonella typhi, Bacillus subtilis and Staphylococcus
aureus respectively as shown in figure-4 but do not showed any
inhibitory action against Pseudomonas aeroginosa. The azo
compound 1d showed 13.6, 12.8, 15.6 and 14.4 mm zones of
inhibition against the test pathogens Escherichia coli,
Salmonella typhi, Pseudomonas aeroginosa and Staphylococcus
aureus as shown in figure-5. Compound 1d showed 11.3 mm
zone of inhibition against the pathogen Bacillus subtilis.
R
NH2
NaNO2 +HCl
0-5oC
N=N Cl
1
C2H5O
2R
C2H5O
5-10 oC
N=N Ar
1a-d
OH
CHO
OH
CHO
Ar =
O2N
CH3
a b c d Figure-1
The general reaction scheme for synthesis of azo compounds of ethyl vanillin
Table-1
The symbols, compounds name, molecular formulae, molecular weights, melting points and percentage yield of synthesized
azo compounds of ethyl vanillin
Symbols for
antimicrobial
activity
Symbols
for
FTIR and
H1 NMR
Compounds
Name
Molecular
Formulae
Molecular
Weights
Melting
points
(0C)
Yield
(%)
1a 4P 3-ethoxy-4-hydroxy-5-
(phenyldiazenyl)benzaldehyde C15H14N2O3 270.28 67 67
1b 4Q 3-ethoxy-4-hydroxy-5-((2-
nitrophenyl)diazenyl)benzaldehyde C15H13N3O5 315.28 128-130 65
1c 4R 3-ethoxy-4-hydroxy-5-(p-
tolyldiazenyl)benzaldehyde C16H16N2O3 284.31 64 72
1d 4S 3-ethoxy-4-hydroxy-5-(napthalen-1-
yldiazenyl)benzaldehyde C19H16N2O3 320.34 127-129 80
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 22
Table-2
FTIR and H1 NMR data of synthesized azo compounds of ethyl vanillin
Symbols for
compounds Types of spectra FTIR and H
1 NMR spectral data
4P
FTIR (KBr,cm-1
) 3362 (OH of Phenol), 2829 (C-H of H-C=O), 1686 (C=O), 1516 (C=C), 1255 (C-O),
1280 (C-N), 1579 (N=N).
H1 NMR (δ ppm)
1.4 (t, 3H of -CH3), 4.2 (q, 2H of -OCH2), 6.2 (s, 1H of Phenolic -OH), 9.8 (s, 1H of -
CHO), 7.0 to 7.5 (m, 7H of Aromatic-H).
4Q
FTIR (KBr,cm-1
) 3398 (OH of Phenol), 2882 (C-H of H-C=O), 1673 (C=O), 1519 (C=C), 1262 (C-O),
1232 (C-N), 1590 (N=N).
H1 NMR (δ ppm)
1.5 (t, 3H of -CH3), 4.4 (q, 2H of -OCH2), 4.2 (s, 1H of Phenolic -OH), 9.8 (s, 1H of -
CHO), 7.0 to 8.5 (m, 6H of Aromatic-H), 9.9 due to moisture.
4R
FTIR (KBr,cm-1
) 3363 (OH of Phenol), 2828 (C-H of H-C=O), 1681 (C=O), 1514 (C=C), 1281 (C-O),
1168 (C-N), 1580 (N=N).
H1 NMR (δ ppm)
1.5 (t, 3H of -CH3), 4.3 (q, 2H of -OCH2), 6.3 (s, 1H of Phenolic -OH), 9.8 (s, 1H of -
CHO), 7.0 to 7.4 (m, 6H of Aromatic-H).
4S
FTIR (KBr,cm-1
) 3333 (OH of Phenol), 2842 (C-H of H-C=O), 1682 (C=O), 1515 (C=C), 1261 (C-O),
1231 (C-N), 1592 (N=N).
H1 NMR (δ ppm)
1.5 (t, 3H of -CH3), 4.1 (q, 2H of -OCH2), 4.3 (s, 1H of Phenolic -OH), 9.8 (s, 1H of -
CHO), 7.0 to 8.5 (m, 9H of Aromatic-H).
Table-3
Antimicrobial activities of the synthesized azo compounds of ethyl vanillin
Symbols for
compounds
Microbial species and diameter of zone of inhibition in mm
Escherichia coli Salmonella typhi Pseudomonas
aeroginosa Bacillus subtilis
Staphylococcus
aureus
1a 10.4 No inhibition No inhibition No inhibition 9.6
1b 10.6 12.7 No inhibition 11.8 9.8
1c 10.3 13.1 No inhibition 13.5 12.8
1d 13.6 12.8 15.6 11.3 14.4
E. coli S. aureus
Figure-2
Zone of inhibition of azo compound 1a
E. coli S. typhi B. subtilis S. aureus
Figure-3
Zone of inhibition of azo compound 1b
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 23
E. coli S. typhi B. subtilis S.aureus
Figure-4
Zone of inhibition of azo compound 1c
E. coli S. typhi P. aeroginosa S.aureus
Figure-5
Zone of inhibition of azo compound 1d
Pagariya-21.sp - 4/21/2014 - 4P
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
0.0
5
10
15
20
25
30
35
40
45
50
55.4
cm-1
%T
3729,53
3362,13
2979,302934,29
2887,34
2829,29
2797,322722,35
2681,402539,42
2331,45
2097,49 1908,49
1782,52
1686,71674,8
1604,18
1579,51516,7
1477,29
1439,17
1398,261380,27
1280,4
1255,9
1197,14
1168,4
1115,101104,10
1041,15
970,23
890,37
852,27
839,20
802,27
786,21
734,40
653,27633,25
585,28524,26
416,47
Figure-6
FTIR spectrum of azo compound 1a
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 24
Pagariya-22.sp - 4/21/2014 - 4Q
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
31.5
35
40
45
50
55
60
65.4
cm-1
%T
3398,57
2982,56
2926,582882,59
2843,58
2757,60
1673,37
1590,41
1519,38
1441,41
1335,48
1308,41
1262,34
1232,42
1126,43
1041,48
878,45851,45
829,45742,42
639,45
590,51
530,54
Figure-7
FTIR spectrum of azo compound 1b
S K Pagariya-1.sp - 5/12/2015 - 4R
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
7.0
8
10
12
14
16
18
20
22
24
26
28
30
32
33.5
cm-1
%T
3778,31
3363,17
2980,202934,19
2887,20
2828,192796,20
2724,20
2540,23
2321,24
2096,27
1907,28
1681,111580,11
1514,11
1439,14
1396,171382,17
1281,101257,11
1168,10
1107,12
1040,13
969,16
889,21
837,16
801,18
783,16633,16
584,18522,19
415,30
Figure-8
FTIR spectrum of azo compound 1c
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 25
S K Pagariya-2.sp - 5/12/2015 - 4S
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 400.0
2.0
4
6
8
10
12
14
16
18
18.7
cm-1
%T
3333,14
3054,12
2981,10
2927,112882,12
2842,11
2758,13
2351,16
2007,181938,18
1871,17
1682,4
1592,51515,6
1487,6
1442,51401,6
1308,51283,5
1261,4
1231,5
1165,7
1136,5
1041,81003,8
878,6860,6
828,6795,6
767,5
741,6716,5
638,6
590,8574,8
545,9
489,11
424,14
Figure-9
FTIR spectrum of azo compound 1d
13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
0.0000
1.4622
1.4797
1.4971
4.1735
4.1910
4.2085
4.2260
6.3361
7.0335
7.0538
7.2680
7.4013
7.4200
7.4245
9.8170
3.35
2.20
1.04
1.01
2.06
1.00
Current Data ParametersNAME May13-2014-AdministratorEXPNO 50PROCNO 1
F2 - Acquisition ParametersDate_ 20140513Time 17.32INSTRUM spectPROBHD 5 mm PABBO BB-PULPROG zg30TD 65536SOLVENT CDCl3NS 8DS 2SWH 12019.230 HzFIDRES 0.183399 HzAQ 2.7263477 secRG 287DW 41.600 usecDE 6.00 usecTE 296.7 KD1 1.00000000 secTD0 1
======== CHANNEL f1 ========NUC1 1HP1 10.90 usecPL1 -3.00 dBSFO1 400.1324710 MHz
F2 - Processing parametersSI 32768SF 400.1300064 MHzWDW EMSSB 0LB 0.30 HzGB 0PC 1.00
4PBRUKERAVANCE II 400 NMRSpectrometer
SAIFPanjab UniversityChandigarh
[email protected] Figure-10
H1 NMR spectrum of azo compound 1a
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 26
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
1.2431
1.2542
1.4019
1.4666
1.4743
1.4841
1.4916
1.5016
1.5091
1.5321
1.6176
1.6380
4.0919
4.1092
4.1662
4.1787
4.1831
4.1963
4.2137
4.2310
7.0325
7.0520
7.2635
7.3995
7.4190
7.4232
7.4318
7.4470
7.4673
7.5105
7.5176
7.5474
7.5574
7.5760
7.6299
7.6450
7.6590
7.6634
7.6724
7.6995
7.7180
7.7311
7.7855
8.0220
8.0542
8.0701
8.1306
8.1637
9.8171
9.9354
13.7555
14.5427
2.21
6.97
2.16
1.04
3.57
0.68
1.00
3.45
5.47
4.50
0.56
1.05
0.38
0.36
Current Data ParametersNAME May13-2014-AdministratorEXPNO 60PROCNO 1
F2 - Acquisition ParametersDate_ 20140513Time 17.37INSTRUM spectPROBHD 5 mm PABBO BB-PULPROG zg30TD 65536SOLVENT CDCl3NS 8DS 2SWH 12019.230 HzFIDRES 0.183399 HzAQ 2.7263477 secRG 912DW 41.600 usecDE 6.00 usecTE 296.7 KD1 1.00000000 secTD0 1
======== CHANNEL f1 ========NUC1 1HP1 10.90 usecPL1 -3.00 dBSFO1 400.1324710 MHz
F2 - Processing parametersSI 32768SF 400.1300083 MHzWDW EMSSB 0LB 0.30 HzGB 0PC 1.00
4QBRUKERAVANCE II 400 NMR
SpectrometerSAIFPanjab UniversityChandigarh
[email protected] Figure-11
H1 NMR spectrum of azo compound 1b
13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
0.0000
1.4595
1.4770
1.4945
4.1702
4.1877
4.2052
4.2226
6.3759
7.0331
7.0528
7.2702
7.4008
7.4196
7.4239
9.8151
3.31
2.15
1.00
1.07
2.03
1.01
Current Data ParametersNAME May13-2014-AdministratorEXPNO 70PROCNO 1
F2 - Acquisition ParametersDate_ 20140513Time 17.42INSTRUM spectPROBHD 5 mm PABBO BB-PULPROG zg30TD 65536SOLVENT CDCl3NS 8DS 2SWH 12019.230 HzFIDRES 0.183399 HzAQ 2.7263477 secRG 512DW 41.600 usecDE 6.00 usecTE 296.8 KD1 1.00000000 secTD0 1
======== CHANNEL f1 ========NUC1 1HP1 10.90 usecPL1 -3.00 dBSFO1 400.1324710 MHz
F2 - Processing parametersSI 32768SF 400.1300055 MHzWDW EMSSB 0LB 0.30 HzGB 0PC 1.00
4RBRUKERAVANCE II 400 NMRSpectrometerSAIFPanjab UniversityChandigarh
[email protected] Figure-12
H1 NMR spectrum of azo compound 1c
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 27
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
1.5105
1.5283
1.5551
1.5725
1.5899
1.6178
1.6350
1.6524
4.1694
4.1869
4.2044
4.2239
4.2417
4.2592
4.2766
4.2870
4.3362
4.3539
7.0285
7.0480
7.2588
7.3936
7.4127
7.4987
7.5020
7.5276
7.5420
7.5508
7.5764
7.6001
7.6197
7.6355
7.6403
7.6640
7.6810
7.7272
7.7743
7.7797
7.8555
7.9336
7.9517
7.9716
7.9963
8.0301
8.0430
8.0498
8.0617
8.1352
8.1390
8.4134
8.4831
8.5038
8.5623
9.8137
9.9637
14.8291
1.30
4.64
2.94
0.49
0.70
0.81
1.55
4.88
1.99
2.32
1.17
1.00
0.98
1.01
Current Data ParametersNAME May13-2014-AdministratorEXPNO 80PROCNO 1
F2 - Acquisition ParametersDate_ 20140513Time 17.49INSTRUM spectPROBHD 5 mm PABBO BB-PULPROG zg30TD 65536SOLVENT CDCl3NS 8DS 2SWH 12019.230 HzFIDRES 0.183399 HzAQ 2.7263477 secRG 812DW 41.600 usecDE 6.00 usecTE 297.0 KD1 1.00000000 secTD0 1
======== CHANNEL f1 ========NUC1 1HP1 10.90 usecPL1 -3.00 dBSFO1 400.1324710 MHz
F2 - Processing parametersSI 32768SF 400.1300103 MHzWDW EMSSB 0LB 0.30 HzGB 0PC 1.00
4SBRUKERAVANCE II 400 NMRSpectrometer
SAIFPanjab UniversityChandigarh
[email protected] Figure-13
H1 NMR spectrum of azo compound 1d
Conclusion
The current investigation reveals that, there was a miraculous
inhibition of compound 1d shows antibacterial activity against
all the tested organisms while the compound 1a was found to be
most resistant by the pathogens. The highest zone of inhibition
was obtained for 1d against Pseudomonas aeroginosa (15.6
mm) while lowest zone was recorded for 1a against
Staphylococcus aureus (9.6 mm). The compounds 1b and 1c
shows moderate inhibition of growth against tested pathogens.
References
1. Towns A.D., Developments in azo disperse dyes derived
from heterocyclic diazo compounds, Dyes and Pigments,
42, 3-28 (1999)
2. Zollinger H., Synthesis, properties and applications of
organic dyes and pigments, Color Chemistry, third
revised edition,Wiley-VCH.,Weinheim (2003)
3. Gayatri C. and Ramalingam A.,Z-scan determination of
the third order optical nonlinerities of an azo dye using
dipole: pumped Nd:Yag laser, Optik, 119(9), 409-414
(2008)
4. Sakong C., Kim Y. D., Choi J. H., Yoon C. and Kim J.P.,
The synthesis of thermally stable red dyes for LCD color
filters and analysis of their aggregation and spectral
properties, Dyes and Pigments, 88(2),166-173 (2011)
5. Bae J.S., Freeman H.S. and El-Shafei A., Metallization of
non-genotoxic direct dyes, Dyes and Pigments, 57(2),
121-129 (2003)
6. Sanjay F.T., Dinesh M.P., Manish P.P. and Ranjan G.P.,
Synthesis and antibacterial activity of novel pyraazolo
[3,4-b] quinoline base heterocyclic azo compounds and
their dyeing performance, Saudi Pharm. Journal, 15(1),
48-54 (2007)
7. Child R.G., Wilkinson R.G. and Tomcu-Fucik A., Effect
of substrate orientation of adhesion of polymer joints,
Chem. Abstr., 87, 6031 (1977)
8. Garg H.G. and Prakash C.J., Preparation of 4-arylazo-
3,5-disubstituted-(2H)-1,2,6-thiadizine1,1-dioxides, Med.
Chem.,15(4), 435-436 (1972)
9. Koshti S.M., Sonar J.P., Sonawane A.E., Pawar Y.A.,
Nagle P.S., Mahulikar P.P. and More D.H., Synthesis of
azo compounds containing thymol moiety, Indian J.
Chem., 47B, 329-331 (2008)
10. Pathan R.U. and Borul S.B., Synthesis and antimicrobial
activity of azo compounds containing drug moiety,
Oriental J. Chem., 24(3), 1147-1148 (2008)
Research Journal of Chemical Sciences ___________________________________________________________ ISSN 2231-606X
Vol. 5(7), 20-28, July (2015) Res. J. Chem. Sci.
International Science Congress Association 28
11. Rathod K.M., Synthesis and antimicrobial activity of azo
compounds containing paracetamol moiety, Oriental J.
Chem., 26(3), 1163-1166 (2010)
12. Rathod K.M. and Thakare N.S., Synthesis and
antimicrobial activity of azo compounds containing m-
cresol moiety, Chem. Sci.Trans., 2 (1), 25-28 (2013)
13. Rathod K.M., Synthesis and antimicrobial activity of azo
compounds containing resorcinol moiety, Asian J.
Research Chem., 4(5), 734-736 (2011)
14. Pagariya R.F., Rathod K.M. and Thakare N.S., Synthesis,
characterization and antibacterial screening of azo
compounds containing vanillin moiety, Asian J. Research
Chem., 6(9), 824-827 (2013)
15. Dahake P.R. and Kamble S.I., Investigatory study on
antimicrobial activity and phytochemical screening of
Butea monosperma Linn, BBRA, 11(3), 1695-1698
(2014)
16. Alzoreky N.S. and Nakahara K., Antimicrobial activity
of extracts from some edible plants commonly consumed
in Asia, Int. J. Food Microbial, 80, 223-230 (2003)