A new road for the synthesis and characterization of new enamino benzodiazepines
PhD Viva voce Presentation 19012015 (1)
1. SYNTHESIS AND BIOLOGICAL STUDY OF
NOVEL HETEROCYCLIC SCHIFF BASES
AND ITS TRANSITION METAL COMPLEXES
Research Student : Sudhir Sawant
Research Guide : Dr. Ramesh S. Yamgar
Ph D Viva Voce Presentation
2. “ शुध बीजा पोटी , फळे रसाळ गोमटी |”
( The sweet n cute fruits are the result of purity of
seeds. )
- संत तुकाराम
4. Applied coordination chemistry
Anti cancer Platinum complexes
Jacobsen’s Catalyst
N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediaminomanganese(III) chloride
5. Assymetric synthesis of (R) Fluoxetine
hydrochloride
N
CH3
O
N
CH3
OH
H2 (30 atm), (2S,4S) - MCCPM-Rh(I) cat (30 atm), (2S,4S) - MCCPM-Rh(I) cat(30 atm), (2S,4S) - MCCPM-Rh(I) cat
CH3OH S/C = 1000
50
o
C
N
CH3
O
F3C
. HCl
(R) - Fluoxetine hydrochloride
N
P(C6H5)2
(o-C6H11)2 P
CONHCH3
(2S,4S) - MCCPM
amino ketone 4
90.8% ee
6. Theoretical principles of coordination chemistry
Central metal atom is surrounded by
three ethylene diamine ligand
molecules.
Ethlene diamine is a chelating agent
or ligand with two nitrogen donor
atoms.
'Chele' is Greek word for crab's
claw.
X
M X X
X
M
X= O, N or S M = Metal atom
Chelate forming 5 member ring Chelate forming 6 member ring
Chelate having 5 and 6 membered
rings
7. Physical techniques used for characterisation of
Schiff base transition metal complexes
UV – Visible spectroscopy
1H NMR and 13C NMR spectroscopy
Mass spectroscopy MS/MS
X-ray diffraction
Thermal analysis – DSC/TGA
HPLC
8. Aim of present work
Aldehydes + aliphatic amino compounds
Aldehydes + Aniline compounds
Transition metal complexes containing heterocyclic
Schiff base Ligands having antitubercoulosis activity
4-Methyl umbelliferone has exhibited anti cancer
activity
To prepare transition metal conjugates and explore
the biological activities using schiffs base chemistry
9. Introduction to the chemistry of coumarins
O O
R
CH3
O
O O
CH3
OH H
+
+ RR
Phenol substituted beta keto ester coumarin derivatives
Pechmann condensation using phenol and beta keto ester
N
N
N
N
OH
OO
CH3 CH3
1) glycerol, boric acid 150
o
C
2) H2SO4, H2O
OH
O
CH3
O
CH3
H O
Synthesis of syringaldehyde
10. Formylation procedures for aromatic nucleus
Reimer Teimann reaction : CHCl3/KOH
Vilsmeir Haack formylation : DMF / POCl3
Gatterman formylation: HCl, HCN, AlCl3 or ZnCl2
Duff formylation : HMTA , Acetic acid
OH OH
H
O
Reagent
Reimer Tiemann reaction
11. Literature survey of transition metal complexes
derived from coumarins and heterocyclic anilines
OO
CH3
OH
N
H
R
R= Cl & CH3
O
O
CH3
OH
N
OH
OH OH
+
O
O
O
CH3
CH3
Resorcinol Ethylacetoacetate
Conc. H2SO4
0
o
C
OOH O
CH3
7Hydroxy-4-methyl coumarin
7080
o
C
Hexamine
HCl, water
OOH O
CH3
CHO
ophenylene diamine
reflux 45 Hrs
OOH O
CH3
O OHO
CH3
N N
reflux 45 Hrs ethylene diamine
Schiff base I
O OHO
CH3
N
OOH O
CH3
N
Schiff base II
4- Phenyl semicarbazide
O
O
CH3
H
NN
NH O
M
O
O
CH3
H
N N
NHO
Where M = Divalent transition metal such as Mn, Co, Cu, Ni, Pd
12. Literature survey of 7-hydroxy-4-methyl-2-oxo-
2H- chromone-8-carbaldehyde Schiff bases
4-Methyl umbelliferone
O O
CH3
OH
CHO
O O
CH3
OH
HN
N
8-Aminoquinoline, Ethanol
Refluxing, 12Hr
3 - amino pyridine
O O
CH3
OH
HN
N
O O
CH3
OH
HNNH2
1,8 - diamino napthalene
O O
CH3
OH
HN
N S
N
SH
5 - amino 1,3,4 thiadiazole 2 - thiol
13. Organic Syntheses : Synthesis of ortho
hydroxybenzaldehydes and heterocyclic aniline
compounds
7-hydroxy-4-methyl-2-oxo-2H
-chromene-8-carbaldehyde
O O
CH3
OH
OH
O O
CH3
OH Hexamine, Acetic acid
85 - 90
0
C
Duff formylation of 4-Methyl-7-Hydroxycoumarin
-CHO
-OH
4-Methyl-Umbelliferone
14. Synthesis of Ethyl 2-(3-formyl-4-hydroxyphenyl)-4-
ethyl-1,3-thiazole-5- carboxylate
15. Chemistry of amino compounds
Nitrogen atom forms the core of many
heterocyclic drug molecules, DNA
Heterocycles form by far the largest of classical
divisions of organic chemistry
16. Synthesis of N,N- dimethylamino propyl amine
(DMAPA) and N-methylamino propyl amine (NMAPA)
CH2
N
CH3 NH2
OH
-
CH3 NH
N
CH3 NH
NH2
CH3 N
N
CH3
CH3 N
NH2
CH3
Raney Ni / H2
Raney Ni / H2
CH3 NH CH3
Raney Ni / H2
OH
N
Raney Ni / H2
OH
NH2
DMAPA
NMPDA
3Amino propanol
CH2 NCH3
NH
CH3
1
2
3
4
. .
CH3
N
+
CH3
N
H
CH3
-
CH3
N
CH3
N
Donor Acceptor Transition state
Michael addition mechanism
17. Synthesis of heterocyclic aniline compounds
OH
OH
Cl
N
CH3
CH3
ClH+
Sodium methoxide
Chlorobenzene
O
OH
N
CH3
CH3
10% NH3 in ethanol
Ra Ni catalyst
O
NH2
N
CH3
CH3
4-Hydroxy benzaldehyde
2-chloro-N,N-dimethylethanamine
hydrochloride
4-[2-(dimethylamino)ethoxy]
benzaldehyde
2-[4-(aminomethyl)phenoxy]-
N,N-dimethylethanamine
"in situ"
Synthesis of 2-[4-(aminomethyl)phenoxy]-N,N-dimethylethanamine
1HNMR:[ 300 MHz, DMSO-d6] 2.22( s, 6H), 2.59 (t, 2H), 3.86( br s, 2H), 4.05(t, 2H), 6.96(d, 2H, J=6.7Hz), 7.33(d, 2H, J=7.3Hz)
MS : [M+1] 293
IR: ν NH2: 3278cm-1
18. Synthesis of 4-(4-aminobenzyl)-1,3-oxazolidine-2-one
NH2
O
CH3
O
N
+O
-
O
n Butyl Chloroformate
Na2CO3
NH
O
CH3
O
N
+O
-
O O
O CH3
H2 / Pd/C
NH
O
CH3
O
NH2
O
O CH3
NaBH 4 / nButanol
NH
OH
NH2
O
O CH3NH
O
NH2
O
NaOMe , nButanol
4-(4-aminobenzyl)-1,3-oxazolidin
-2-one
ClH
L-4-Nitrophenylalanine hydrochloride Carbamate intermediate III
aniline intermediate IV
Intermediate V
19. Synthesis of 4-(1H-1,2,4-triazol-1-yl methyl) aniline
Br
N
+
O
-
O
1-(bromomethyl)-4-nitrobenzene
NH
N
N
NaOH, Methanol
25
-
30°C
+
1H-1,2,4-triazole N
+
O
-
O
N N
N
1-(4-nitrobenzyl)-1H-1,2,4-
triazole
NH2
N N
N
H2 / Pd/C 40 psi
Methanol
4-(1H-1,2,4-triazol-1-ylmethyl)
aniline
1H NMR (300 MHz, DMSO-d6): 5.24(s, CH2), 6.51(2H, d, J=9Hz, aromatic), 7.03( 2H, J=9Hz, aromatic), 8.02( 1H,s, triazole aromatic),
8.7(1H, s, aromatic triazole).
MS: [M+1]+ 175.
IR: ν NH2 3413cm-1
20. Synthesis of 2-Butyl-5-amino-1-benzofuran
N
+
O
-
O Br
OH
2-(bromomethyl)-4-
nitrophenol
PPh3 CHCl3 N
+
O
-
O
OH
PPh3
Cl
O
CH3
N
+
O
-
O
O
CH3
2-butyl-5-nitro-1-benzofuran
+
Phosphonium ylide
NH2
O
CH3
HCOONH4 Pd/C
HCl gas in Methanol
2-Hydroxy-5-Nitro benzyltriphenyl
phosphonium bromide
2-butyl-5-amino-1-benzofuran
1H NMR:[ 300MHz, DMSO-d6] 0.97(m, 3H), 1.35( m, 2H), 1.73( m, 2H), 2.70( m, 2H), 6.66( s, 1H), 6.94 -6.96( m, 1H),
7.07( d, 1H, J=7.2Hz), 7.39( d 1H, J= 7.2Hz),
MS : [M+1]: 190, IR: νNH2 2954cm-1
21. Chemistry of Schiff bases
R
1
R
2
H
O
+ R
3
NH2
-H2O R
1
R
2
H
N R
3
Formation of Schiff base by condensation reaction ( R group may be variously substituted)
+
R1
R2
N
OH
H
R3
R1
R2
N H
R3
+
OH
-
R1
R2
O
H
R3 N
H
H
:
R1
R2
N
O
H
R3
H
dipolar intermediate carbinolamine
Schiff base
H2O
R1
R2
N H
R3
-
22. Applications of Schiff base metal complexes
Catalysis
Biological & Medicinal
Fluorescent & electronic materials
Dyes
Analytical
O
OH
OH
OH
HO
O
N
HO
N
OH
O
OH
OH
OH
HO
O
MeMe
R R
I
23. Synthesis of novel Schiff base metal complexes
7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde and N-methyl-
propane-1,3-diamine i.e. NMAPIMHMC oxalate salt
Ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methyl-1,3-thiazole-5-carboxylate
and (4S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one i.e. HBOMMTC
Ethyl 2-(3-formyl-4-hydroxyphenyl)-4-methyl-1,3-thiazole-5-carboxylate and
4-(1H-1,2,4-triazol-1-ylmethyl)aniline i.e. HTIMMTC
Ethyl- 2-{ [4-(aminomethyl)phenoxy] N,N- dimethylethylethanamine)]imino}
methyl]-4-methyl-1,3-thiazole-5-carboxylate i.e.EAPDMTC
(4S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one and salicylaldehyde i.e. HBABO
4-(1H-1,2,4-triazol-1-ylmethyl)aniline and salicylaldehyde i.e. TMPIMP
2-[4-(aminomethyl)phenoxy]-N,N-dimethylethanamine and salicylaldehyde
i.e. DMAEBIMP
27. Synthesis of Schiff base Ethyl- 2-{ [4-(aminomethyl)phenoxy] N,N-
dimethylethylethanamine)]imino}methyl]-4-methyl-1,3-thiazole-5-
carboxylate [EAPDMTC]
O
OH
NS
CH3
O
O
CH3
H
NH2
O
N
CH3
CH3
N
O
N
CH3
CH3
OH
NS
CH3
O
O
CH3
H
EAPDMTC
+
Ethyl 2-(3-formyl-4-hydroxyphenyl)-
4-methyl-1,3-thiazole-5-carboxylate
2-[4-(aminomethyl)phenoxy]-
N,N-dimethylethanamine
EtOH
Atom no ppm group
14 168.73 C
2 166.25 C
7 165.75 C ester carbonyl
16 161.45 C azomethine
6 161.18 C
4 160.18 C
28 157.91 C
12 131.14 CH
27 130.80 CH
15 129.65 C
19 , 22 129.25 2 x CH
11 121.83 C
13 118.84 CH
18 118.51 C
20, 21 114.60 2x CH
17 65.78 CH2
23 61.01 CH2
9 59.75 CH2 ester
24 57.64 CH2
25, 26 45.50 2 x CH3 dimethyl amino
5 17.20 CH3 thiazole
10 14.13 CH3 ester
N
O
N
CH3
CH3
OH
NS
CH3
O
O
CH3
H
1
2
3
4
5
6
7
8
9
10
11
12
13
14 15 16
17
18
19
20
21
22
23
24
25
26
27
28
29. Synthesis and characterization of novel
Schiff base metal complexes
Preparation of the Cu(II), Co(II), Ni(II) and Zn(II) complexes of “in situ” Schiff base
derived from 7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde and
N-methylpropane-1,3-diamine
[i] Preparation of [Zn(NMAPIMHMC)2]•2H2O complex
[ii] Preparation of [Cu(NMAPIMHMC)2]•2H2O complex
[iii] Preparation of [Ni(NMAPIMHMC)2] •2H2O complex
[iv] Preparation of [Co(NMAPIMHMC)2]•2H2O complex
OH2
OH2
N
O
H
N
O
H
M
O
O
CH3
O
O
CH3
NH CH3
NHCH3
O O
CH3
OH
NH NH
CH3
O O
CH3
OH
OH
NH2 NH
CH3
MX2. nH2O
M = Zn(II), Cu(II), Ni(II), Co(II)
EtOH, H+
"in situ"
EtOH
7-hydroxy-4-methyl-2-oxo-2H-chromene-8-carbaldehyde NMAPIMHMC
[M(NMAPIMHMC)2].2H2O
N-methylpropane-1,3-diamine
30. Results and discussion
OH
N
NH
CH3
O
CH3
O
H N
Zn
O
O
N
NH
NH
CH3
CH3
O
O
CH3
OO
CH3
HH
OH
O
O
O
CH3
H
8.17 ppm
10.59 ppm
8.83 ppm
Azomethine proton shift values before and after complexation with Zn(II) metal atom
δ value in ppm Schiff
base NMAPIMHMC
δ value in ppm metal complex
[Zn(NMAPIMHMC)2]•2H2O
Multiplicity & Number of Protons Assignment
1.62-1.63 2.06 m ( 2H) C-CH2-C
2.11 2.34 s (3H) -N-CH3
2.41 2.51 s (3H) =C-CH3
2.75 2.96 t (2H) -N-CH2-
3.02 3.73 t (2H) =N-CH2
5.15 5.98 s (1H) =C-H olefinic
5.97 6.56 d (2H) aromatic
6.94 7.56 d (2H) aromatic
8.17 8.83 s (1H) =N-H azomethine
35. Comparison of IR spectra
Complex
Lattice
water
(H2O) cm-1
C=O
Lactonyl
cm-1
C=N
azomethine
cm-1
C-O Phenolic
cm-1
M-N
cm-1
M-O
cm-1
NMAPIMHMC• Oxalate NA 1715 1609 1313 NA NA
[Co(NMAPIMHMC)2]•2H2O 3556 1720 1623 1398 528 449
[Ni(NMAPIMHMC)2]•2H2O 3369 1720 1633 1334 536 457
[Cu(NMAPIMHMC)2]•2H2O 3314 1720 1629 1336 543 457
[Zn(NMAPIMHMC)2]•2H2O 3122 1727 1631 1371 543 453
IR spectra showed appearance of a new strong band in the
region 1620 cm-1to 1630cm-1assigned to the azomethine, ν(C=N)
linkage.
Complex
Mass loss due to H2O
Calculated (%) Observed (%)
[Co(NMAPIMHMC)2]•2H2O 5.61 5.0
[Zn(NMAPIMHMC)2]•2H2O 5.55 5.1
Thermo gravimetric analysis showed significant loss in weight
indicating two molecules of water of crystallization
39. Synthesis of Novel Schiffs base metal complexes
( by template method)
O
OH
H
NH
O
NH2
O
NH
O
N
O
OH
H
OH2OH2
N
O
H
N
O
H
M
NH
O
NH
O O
O
M(HBABO)2.2H2O
M = Zn(II), Cu(II)
HBABO
MX2
salicylaldehyde
(4S)-4-(4-aminobenzyl)-1,3-oxazolidin-2-one
EtOH EtOH
O
OH
H NH2
N
N
N
N
N N
N
OH
H
M(TMPIMP)2. 2H2O
M = Zn(II), Cu(II), Ni(II)
MX2. nH2O
TMPIMP
salicylaldehyde
4-(1H-1,2,4-triazol-1-ylmethyl)aniline
EtOH EtOH
OH2 OH2
N
N N
N
H
O
N
NN
N
H
O
Zn
40. 13C NMR spectrum of [Zn(HBABO)2] complex
Atom No. Group 13C ppm
14,14’ HC=N 163.04
5, 5’ C=O 160.26
20, 20’ C-O-Zn 158.60
10, 10’ C 146.43
7,7’ C 135.48
16, 16’ CH 133.18
18,18’ CH 132.53
8, 8’, 12, 12’ CH 130.49
9,9’,11,11’ CH 121.36
15, 15’ C 119.27
19, 19’ CH 119.10
17,17’ CH 116.55
2, 2’ CH2 67.97
3,3’ CH 52.42
6,6’ CH2 39.90
N
O
H
N
O
H
Zn
NH
O
NH
O O
O
1
2
1'
2'
3
3'
4
4'
5
5'
6
6'
7
7'
8
8'
9
9'
10
10'
11
11'
12
12'
13
13'
14
14'
15
15'
16
16'
17
17'
18
18'
19
19'
20
20'
41. 13C NMR spectrum of [Zn(TMPIMP)2] complex
N
O
H
N
O
H
Zn
NN
N
N N
N
1
2
1'
2'
3
3'
4
4'
5
5'
6
6'
7
7'
8
8'
9
9'
10
10'
11
11'
12
12'
13
13'
14
14'
15
15'
16
16'
17
17'
18
18'
19
19'
20
20'
Atom No. Group 13C ppm
14,14’ HC=N 163.70
20, 20’ C-O-Zn 160.23
2, 2’ CH 151.44
10, 10’ C 147.82
5,5’ CH 144.20
7,7’ C 134.69
16, 16’ CH 133.37
18,18’ CH 132.52
8, 8’, 12,12’ 12’ CH 129.12
9,9’,11,11’ CH 121.60
15, 15’ C 119.24
17,17’ CH 119.16
19, 19’ CH 116.58
6,6’ CH2 51.77
42. 13C Spectrum of Zn(BBFIMP)2 complex
OH2
OH2
N
O
H
N
O
H
Zn
O
CH3
O
CH3 1
1'
2
2'
3
3'
4
4'
5
5'
6
6'
7
7'
8
8'
9
9'
10
10'
11
11'
1212'
13
13'
14
14'
15
15'
16
16'
17
17'
18
18'
19
19'
20
20'
Atom No Assignment 13C PPM
14, 14’ CH Azomethine 162.23
20, 20’ C 160.79
9, 9’ C 160.21
6, 6’ C 150.34
2, 2’ C 143.30
18, 18’ CH 132.83
16,16’ CH 132.43
4, 4’ C 129.52
15, 15’ C 119.36
7, 7’ CH 119.03
17, 17’ CH 117.37
19,19’ CH 116.50
5, 5’ CH 112.46
8, 8’ CH 111.19
3, 3’ CH 102.36
10, 10’ CH2 29.14
11, 11’ CH2 27.37
12, 12’ CH2 21.86
13, 13’ CH3 13.56
43. PXRD study of Zn complexes
XRPD plot of [Zn(DMAPIMMTC)2]•2H2O XRPD plot of [Zn(EBBFCTC)2]•2H2O
XRPD plot of [Zn(HBABO)2]•2H2O complex XRPD plot of [Cu(TMPIMP)2]•2H2O
44. Conclusion
OH2OH2
N
O
H
N
O
H
M
NH
O
NH
O O
O
[M(HBABO)2]•2H2O, M= Zn(II) and
Cu(II)
OH2OH2
N
O
H
N
O
H
M
N
N N
N
NN
[M(TMPIMP)2]•2H2O, M= Zn(II),
Cu(II) and Ni(II)
OH2OH2
N
O
H
N
O
H
M
O
O
N CH3
CH3
NCH3
CH3
[M (DMABIMP)2]•2H2O, M= Zn(II),
Cu(II) and Ni(II)
OH2
OH2
N
O
H
N
O
H
M
O
CH
O
CH3
[M(BBFIMP)2]•2H2O, M= Zn(II) and
Cu(II)
45. Biological study of novel Coumarine Schiff bases
and their metal complexes
Test compound Escherichia coli Aspergillus niger
Schiffs base [NMAPIMHMC] <200 <200
Co[NMAPIMHMC]2.2H2O <20 <20
Ni[NMAPIMHMC]2.2H2O <20 <20
Cu[NMAPIMHMC]2.2H2O <20 <20
Zn[NMAPIMHMC]2.2H2O <20 <20
Antimicrobial Activity (MIC, µg ml-1) of Schiff base [NMAPIMHMC]and its metal complexes
Conclusion: antimicrobial activity of the ligand is enhanced
on complex formation
46. Anti bacterial and antifungal studies of Zinc metal
complexes ( MIC method)
47.
48. Results & discussion
Schiffs base and metal complexes comparative antifungal screening results by MIC method
Conclusion : [Zn(NMAPIMHMC)2].2H2O, [Zn(TMPIMP)2].2H2O and
[Zn(HBABO)2].2H2O complex showed most promising activity upto
3.2 - 1.6µg/ml, compared to standard Fluconazole having MIC value
8µg/ml in A. niger.
Test
Organism
Test sample MIC
C.albicans
NMAPIMHMC 50
Zn(NMAPIMHMC)2 3.12
TMPIMP 50
Zn(TMPIMP)2 3.12
HBABO 12.5
Zn(HBABO)2 25
Std. Flucanazole 16
A.niger
NMAPIMHMC 0.8
Zn(NMAPIMHMC)2 0.8
TMPIMP 1.6
Zn(TMPIMP)2 3.12
HBABO 6.25
Zn(HBABO)2 3.12
Std. Flucanazole 8
49. Results & discussion
Conclusion: Zn(NMAPIMHMC)2].2H2O, [Zn(DMAPIMMTC)2].2H2O
and [Zn(HBABO)2].2H2O as a metal containing complex of potential
therapeutic benefit, particularly for the topical treatment as antifungal
agent against C.albicans and A.niger.
Test
Organism
Test sample MIC
C.albicans
Zn(DMAEBIMP)2 12.5
Zn(HBABO)2 3.12
Zn(NMAPIMHMC)2 3.12
Zn(BBFIMP)2 100
Zn(DMAPIMMTC)2 1.6
Std. Flucanazole 16
A.niger
Zn(DMAEBIMP)2 0.4
Zn(HBABO)2 0.2
Zn(NMAPIMHMC)2 0.2
Zn(BBFIMP)2 0.2
Zn(DMAPIMMTC)2 0.4
Std. Flucanazole 8
50. Anti tuberculosis study of Zinc complexes
Test Organism Test sample
concentration in
μg/ml
M.Tuberculosis
1. Zn(DMAPIMMTC)2 25
2. Zn(NMAPIMHMC)2 25
3. Zn(HBABO)2 12.5
4. Zn(DMAEBIMP)2 25
5. Zn(BBFIMP)2 25
Std. Pyrazinamide 3.125
Std. Steptomycin 6.25
Conclusion : Zinc(II) complexes have shown moderate activity as
compared to standard Pyrazinamide and Streptomycin against
M.Tuberculosis
51. List of publications
1. Ramesh S. Yamgar, Prasad Kamat and Sudhir S. Sawant, Synthesis of Schiff base zinc metal complex (MAPIMP)2Zn and
development of HPLC chromatographic method for its analysis, J. Chem. Pharm. Res., 2010, 2(5): 216-224.
2. Ramesh Yamgar, Prasad Kamat, Dileep Khandekar & Sudhir Sawant, Preparation of Schiff base Zinc Metal complex (DMAPIMP)2Zn
and Development of HPLC Chromatographic method for its analysis., J. Chem. Pharm. Res., 2011, 3(1), 188-198.
3. M. Mustapha, B. R. Thorat, Sudhir Sawant, R. G. Atram and Ramesh Yamgar
Synthesis of novel Schiff bases and its transition metal complexes, J. Chem. Pharm. Res., 2011, 3(4), 5-9.
4. Sangeeta V. Chavan, Ramesh S. Yamgar and Sudhir S. Sawant, Synthesis and Characterization of Novel Transition Metal
Complexes of Benzo-Pyranone Derivatives and Their Biological Activities, Asian J. Research Chem., 2011, 4(5), 834-837.
5. Vijaya Pawar, Sangeeta V. Chavan, Ramesh S. Yamgar, R. G. Atram, B.R. Thorat, Swati Bisht and Sudhir S. Sawant,
Synthesis and Characterization of Novel Transition Metal Complexes of 4-Methyl-7-Hydroxy-8-Formyl Coumarin and Their
Biological Activities, Asian J. Research Chem. 2011, 4(8), 1238-1242.
6. Sudhir S. Sawant , Vijaya Pawar, Shirish Janrao, Ramesh S. Yamgar and Y. Nivid,
Synthesis and Characterization of Transition Metal Complexes of Novel Schiff base 8-[(z)-{[3-(N-methylamino)propyl]imino}
methyl]-7-hydroxy-4-methyl-2h- chromen-2-one][NMAPIMHMC] and their Biological activities, International Journal of Research in
Pharmacy and Chemistry, 2013, 3(3), 636- 644.
7. Ramesh S. Yamgar, Y.Nivid and Sudhir S. Sawant, Synthesis, Characterisation and Anti tuberculosis activity of novel transition metal
complexes of heterocyclic Schiff bases, International Journal of Advanced Research in Applied Chemistry, 2013, 1(9), 1-21.
8. Ramesh S. Yamgar, Y.Nivid, Satish Nalawade, Mustapha Mandewale, R. G. Atram and Sudhir S. Sawant, Novel Zinc (II) complexes of
Heterocyclic ligands as antimicrobial agents: Synthesis, characterisation and antimicrobial studies, Bioinorganic Chemistry and
Applications, 2014, doi:10.1155/2014/276598.