ISSN (P): 2349-8242 Synthesis, characterisation ...€¦ · reaction was assessed by TLC and...

~ 341 ~

The Pharma Innovation Journal 2018; 7(10): 341-351

ISSN (E): 2277- 7695

ISSN (P): 2349-8242

NAAS Rating: 5.03

TPI 2018; 7(10): 341-351

© 2018 TPI

www.thepharmajournal.com

Received: 16-08-2018

Accepted: 18-09-2018

Maddumala Sowjanya

Department of Pharmaceutical

Chemistry, Sri Chundi

Ronganakulu College,

Chilakalurpet, Andhra Pradesh,

India

Baratam Anupama


Chemistry, KVSR Siddhartha

College of Pharmaceutical

Sciences, Vijayawada, Andhra

Pradesh, India

R Satyavani





Pradesh, India

M Manoj Kumar





Pradesh, India

KNV Chenchu Lakshmi

Assistant Professor,




Sciences, Vijayawada,

Andhra Pradesh, India

Correspondence

KNV Chenchu Lakshmi

Assistant Professor,




Sciences, Vijayawada,

Andhra Pradesh, India

Synthesis, characterisation, physiochemical properties

and biological evaluation of some novel 2-(3-oxo-

dihydro-2h-indol-2-ylidene) hydrazinecarboxmide

Schiff bases

Maddumala Sowjanya, Baratam Anupama, R Satyavani, M Manoj

Kumar and KNV Chenchu Lakshmi

Abstract Novel 2-(2-oxo-dihydro-2H-indol-2-ylidene) hydrazine carboxmide Schiff bases (1s-14s) were

synthesized by reacting various aliphatic and aromatic (substituted & unsubstituted) amines with isatin -

3-semicarbazone under strong basic conditions by conventional method. The purity and progress of

reaction was assessed by TLC and melting point. Synthesised compounds were characterised by various

spectroscopic methods such as IR, H1 &C13 NMR. Physical parameters such as isoelectric point, logP

and logD, pka, solubility (Log S and mg/ml) were determined by Chem Axon Chemicalize instant

Cheminformatics solution software. The synthesised Schiff bases were evaluated for their

antibacterial(two gram-positive bacteria Staphylococcus aureus ATCC 6538 and Bacillus subtilis ATCC

6633 and two Gram-negative bacteria Escherichia coli ATCC 8739 and Pseudomonas aeruginosa ATCC

9027), antifungal (Aspergilus Niger MTCC 282 and Pencillium notatum NCIM 742,) and antioxidant

activities(DPPH Free radical scavenging assay). The results of Chem Axon revealed that compounds had

very low solubility in polar solvents, isoelectric point (6.5-8.5), log p (0-3.5), acidic pKa (8-9) basic pKa

(5-8).Antimicrobial studies revealed that compounds 3s, 5s, 7s and 12s possess good antibacterial and

antifungal properties. Compounds 5s, 7s, 8s, 11s, 12s exhibited better free radical scavenging assayof all

the compounds, 12s found to possess good antimicrobial and antioxidant activities. The study provides a

good scope for further development of novel targeted molecules.

Keywords: Schiff bases, anti-bacterial, anti-fungal, antioxidant, Chemaxon

1. Introduction

Schiff bases are condensation products of primary amines with carbonyl compounds and they

were first reported by Hugo Schiff [1] in 1864.The common structural features of these

compounds is the azomethine group with a general formula RHC=N-R1 where R & R1 are

alkyl, aryl, cyclo alkyl or heterocyclic group which may be variously substituted. These

compounds are also known as anils, imines or azomethines.

Schiff basesare used as substrates in the preparation of a number of industrial and biologically

active compounds via ring closure, cycloaddition and replacement reactions [2].Moreover,

Schiff bases derived from various heterocycles have been reported to possess cytotoxic [3],

anticonvulsant [4], antiproliferative [5], antimicrobial [6], anticancer [7], and antifungal [8]

activities. They have been encountered with antibacterial [9], anticancer, analgesic and anti-inflammatory, anticonvulsant, antimalarial, antiviral and CNS depressant activities. Isatin,

chemically known as 1H-indole-2, 3-dione, has become a popular topic due to its various uses. The

chemistry of Isatin and its derivatives is particularly interesting because of their potential

application in medicinal chemistry. Isatins are very important compounds due to their antifungal

properties. Schiff and Mannich bases of isatin derivatives are reported to show variety of biological

activities like antibacterial, antifungal [11], anti-convulsant, anti HIV, antidepressant, and anti-

inflammatory activities.

2. Materials and methods

Melting points were determined in open glass capillaries using Tempo (600) melting point

apparatus and were uncorrected. IR spectra (KBr discs) Bruker analysers were confirmed by

Shimadzu FT-IR Spectrophotometer using KBr pellets technique, Model No.8400S (Japan). 1H and

13C NMR spectra were recorded on Bruker 400 MHz NMR spectrometer (Switzerland) using

DMSO as solvent.

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The Pharma Innovation Journal

T.L.C. was run on silica gel G plates using ethyl acetate: n-

hexane (5:5) as developing solvent to assess the progress of

reaction and purity of the compounds. All other chemicals

used in the present study were of analytical grade.

2.1. Drugs and Chemicals Isatin-(LOBA-B.NO-0421100100), Semicarbazide-(LOBA-

B.NO-0568300100), Ortho phenylene diamine-(LOBA-

B.NO-0520700250), Sodium Hydroxide-(LOBA-B.NO-

0590000500), SilicagelG-(LOBA-B.NO-0570001000), Ethyl

Acetate-(LOBA-B.NO-0013702500), n-Hexane-(LOBA-

B.NO-0016102500), Dimethyl Sulphoxide -(LOBA-B.NO-

0012300500), 1-Naphthylamine- (SD FINE CHEM

LIMITED- B.NO- 1198/0598/3108/02), Ethyl amine-(LOBA-

B.NO-037180000), Methyl amine-(LOBA-B.NO-

4606H00500), Isopropyl amine-(Merck-B.NO-SH7B570229),

Aniline-(LOBA-B.NO-0003200500), 4-chloro aniline-

(LOBA-B.NO-0273300500), 4-Bromo aniline-(LOBA-B.NO-

0570001000), 4-Nitro aniline-(LOBA-B.NO-0492700250), 2-

Amino pyridine-(LOBA-B.NO-0570001024), 2Amino

pyrimidine-(Alderch-B.NO-A78608), 4-Amino phenol-(Otto-

B.NO-0117),6-Amino uracil-(), Hydroxyl amine

hydrochloride-(-B.NO-1402025), Ascorbic acid -(LOBA-

B.NO- 0154900500), Methanol-(FINAR CHEMICAL

LIMITED), Potassium Hydroxide-(OXFORD

LABORATARIES).

2.2 General procedure

Synthesis of (2z)-2-(3-oxo-dihydro-2H-indol-2-ylidene)

hydrazinecarboxmide Schiff bases [23-24]:

Isatin 3 Semicarbazone were prepared by condensation of

0.01 moles of Isatinwith 0.02 moles of Semicarbazide HCl in

presence glacial acetic acid and hot water. The reaction

mixture was refluxed for 4hr. The reaction mixture was

cooled; precipitate was filtered, dried, recrystallized from

methanol and confirmed by thin layer chromatography and

melting point.(2z)-2-(2-oxo-dihydro-2H-indol-2-ylidene)

hydrazine carboxmide Schiff bases synthesis was preceded by

condensation of equimoles (0.001moles) of step 1 with

various aliphatic &aromatic amines in methanol and few

drops of 40% KOH. The reaction mixture was refluxed for

4hr, cooled; the product formed was filtered, dried and

recrystallized from methanol. the progress and the purity of

the reaction was confirmed by thin layer chromatography and

melting point. The procedure was illustrated under Scheme

1&the physical data of the compounds were represented in

Table 1. The physical characteristics of the molecules were

assessed by Chem Axon’s Chemicalize instant

Cheminformatics solution software and the results were

tabulated in Tables 2, Table 3.The characterisation of the

molecules done by IR, C13NMR and H1 NMR data were

tabulated in Table 4, Table 5 and Table 6.

NH

O

O + NH2

NH NH2

O Condensation

CH3COOH,H2O

KOH in Methanol

R/Ar-NH2

Condensation

IsatinSemicarbazide

Isatin

Heat,3-

Heat,

NH

O

N

NH

NH2

N

R/Ar

NH

N

O

NH

NH2

O

(1s-14s)

Scheme 1Compounds (1s-14s)

1s.—CH3, 2s.-C3H6, 3s.-C10H7, 4s.-C6H6, 5s.-C6H5, 6s.-C6H4Cl-p, 7s.-C6H4NO2,

8s.-C6H4Br, 9s.C5H4N, 10s.-C4H3N2, 11s.-C6H5O, 12s.-C6H7N2O213s.-OH14s.C2H5

~ 343 ~


Table 1: Physical Data

Compound IUPAC Name MF MW Physical state

MP(O)C %

ylide Colour State

1s (2z)-N1-methyl (-2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)hydrazine

carboximidamide C10H11N5O 217.23 Yellow solid 210 63

2s (2z)-N1,N1-DImethyl (-2-(3-oxo-1,2-dihydro-3H-indol-3-

ylidene)hydrazine-1- carboximidamide C12H15N5O 245.29 Yellow solid 240 65

3s (2z)-N1-(naphthalene-2-yl)

-2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)hydrazine carboximidamide C19H15N5O 329.36 Yellow solid 250 62

4s (2z)-N1-(4-aminophenyl)-2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)hydrazine carboximidamide C15H14N6O 294.32

Greenish

grey solid 240 70

5s (2z)- 2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)N1-

phenylhydrazinecarboximidamide C15H13N5O 279.30 Yellow solid 240 72

6s (2z)-N1-(4-chloro phenyl-2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)hydrazine carboximidamide C15H12ClN5O 313.75 Yellow solid 260 68

7s (2z)-N1-(4-nitro phenyl)-2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)hydrazine carboximidamide C15H12N6O3 324.30 Brown solid 260 80

8s (2z)-N1-(4-bromo phenyl)-2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)hydrazine carboximidamide C15H12BrN5O 358.20 Yellow solid 260 65

9s (2z)-2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)-N1-pyridin-3-yl)

hydrazine carboximidamide C14H12N6O 280.29 Yellow solid 250 67

10s (2z)-N1-(pyrimidin-4yl)-2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)hydrazine carboximidamide C13H11N7O 281.28 Yellow solid 260 66

11s (2z)-N1-(4-hydroxyphenyl)- 2-(3-oxo-1,3-dihydro-2H-indol-2-

ylidene)-hydrazine carboximidamide C15H13N5O2 295.30 Black solid 260 72

12s (2z)-N1-(2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)2-(3-oxo-1,3-

dihydro-2H-indol-2-ylidene)hydrazine carboximidamide C13H11N7O3 313.28 Yellow solid 290 77

13s (2z)-N1-hydroxy2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)hydrazine

carboximidamide C9H9N5O2 219.20 Yellow solid 240 67

14s (2z)-N1-ethyl (-2-(3-oxo-1,3-dihydro-2H-indol-2-ylidene)hydrazine

carboximidamide C11H13N5O 231.26 Yellow solid 230 69

Table 2: physico-chemical properties by Chem Axon chemicalize [10]

compound Elemental

composition

Solubility Pka

Log s mg/ml

1s

C%-55.29,

H%-5.1,

N%-32.2,

O%-7.3

2s

C%-58.76,

H%-6.16,

N%-28.5,

O%-6.5

3s

C%-69.2,

H%-4.5,

N%-21.2,

O%-4.8

~ 344 ~


4s

C%-61.2,

H%-4.7,

N%-28.5,

O%-5.4

5s

C%-64.5,

H%-4.6,

N%-25.08,

O%-5.7

6s

C%-57.4,

H%-3.8,

N%-11.3,

O%-5.1,

Cl%-11.3

7s

C%-55.5,

H%-3.7,

N%-25.9,

O%-14.8

8s

C%-50.3,

H%-3.3,

N%-19.5,

O%-4.4,

Br%-22.3

9s

C%-59.9,

H%-4.32,

N%-29.9,

O%-5.7

~ 345 ~


10s

C%-55.5,

H%-3.9,

N%-34.8,

O%-5.6

11s

C%-61.01,

H%-4.4,

N%-23.7,

O%-10.8

12s

C%-49.8,

H%-3.5,

N%-31.3,

O%-15.3

13s

C%-61.2,

H%-4.7,

N%-28.5,

O%-5.4

14s

C%-57.1,

H%-5.6,

N%-30.2,

O%-6.9

Table 3: physic-chemical properties by Chem Axon

Compound Ionization constant Log p & Log D RF

1s

0.7

~ 346 ~


2s

0.7

3s

0.7

4s

0.69

5s

0.7

6s

0.7

7s

0.7

~ 347 ~


78s

0.7

9s

0.7

10s

0.7

11s

0.7

12s

0.7

13s

0.7

~ 348 ~


14s

0.7

Table 4: Characteristics IR absorption bands of synthesized compounds

Compound C-H C-N C-OH N-H C=O 10- NH2 Ar-NO2 C-Cl C-Br

1s 3188.17 1349.62 3668.58 1791.21 3743.05, 3616.75

2s 3195.41 1100.58 3464.32 1701.00 3552.85, 3613.72

3s 3037.00 1283.10 3411.34 1735.61 3605.28, 3637.41

4s 3197.73 1386.27 3462.73 1694.87 3615.67, 3668.14

5s 3128.12 1344.30 3465.95 1694.75 3555.10, 3616.27

6s 3099.58 1345.27 3465.22 1703.86 3607.08, 3668.31 787.94

7s 3004.02 1299.48 3471.20 1704.76 3554.29, 3606.81 1394.17, 1578.82

8s 3085.30 1345.41 3467.58 1691.49 3615.70, 3666.61 668.38

9s 3129.09 1195.42 3465.34 1691.69 3553.34, 3615.79

10s 3189.32 1391.72 3464.70 1691.07 3615.19, 3675.05

11s 3000.66 1389.03 3220.16 3466.58 1706.92 3614.78, 3667.45

12s 3086.48 1234.96 3464.82 1719.12 3615.67, 3666.58

13s 3196.33 1387.32 3464.43 1703.44 3606.90, 3668.48

14s 3195.65 1390.22 3464.10 1690.97 3616.77, 3668.32

Table 5: C13NMR.

Compound C=O Aromatic Carbons (Ar-c) C-N C=N C-Cl C-OH C-NO2 C-Br

1s 206 111.8,125.2,122.3,125.2,123.4,125.3,122.3 125.2 140.1

2s 208 120.3,125.2,122.3,125.2,123.4,125.3,122.3 122.3 142

3s 199 125.2,125.2,122.3,125.2,123.4,125.3,122.3 125.2 146.3

4s 200 128.8,125.2,122.3,125.2,123.4,125.3,122.3 122.5 150

5s 202 122.3,125.2,122.3,125.2,123.4,125.3,122.3 124.3 152.8

6s 207 102.2,122.3,125.2,123.4,125.3,122.3,121.3 123.2 148.2 46.5

7s 205 121.3,120.3,125.2,122.3,125.2,123.4,125.3 126.3 145.6 76.2

8s 209 112.2,120.3,125.2,122.3,125.2,123.4,125.3 122.3 157.3 52.8

9s 214 124.3,120.3,125.2,122.3,125.2,123.4,125.3 125.3 153.9

10s 220 114.4,121.3,120.3,125.2,122.3,125.2,123.4, 124.3 150.0

11s 202 119.2,121.3,120.3,125.2,122.3,125.2,123.4, 122.3 155.3 150.2

12s 208 120.4,119.2,121.3,120.3,125.2,122.3, 125.2 122.2 149.2

13s 204 123.2,120.4,119.2,121.3,120.3,125.2,122.3 125.3 147.5

14s 201 125.2,114.4,121.3,120.3,125.2,122.3, 125.2, 123.2 154.7

Table 6: 1HNMR.

compound Hydrogens (n) δ(ppm) Multiplicity Solvents

1s

Ar

NH

NH2

CH=N

N-NH

6.771-7.422

9.109

1.764

4.120

8.816

(sx),(q)

Singlet

Singlet

Singlet

Singlet

DMSO

2s

Ar

NH,

NH2

C-CH

N-NH

6.771-7.422

8.744

1.981

1.191

8.853

(sx)(q)

Singlet

Singlet

Doublet

Singlet

DMSO

3s

Ar,

NH,

NH2

N-NH

6.441-7.839

9.764

1.810

12.751

(sx)(q)(t)

Singlet

Singlet

Singlet

DMSO

4s

Ar

NH,

NH2

6.637-7.422

10.244

1.934,4.695

(q),(d),(sx)

Singlet

Singlet

DMSO

~ 349 ~


N-NH 12.784 Singlet

5s

Ar

NH

NH2

N-NH

6.771-7.422

9.325

2.709

12.758

(n)(q)(sx)(t)

Singlet

Singlet

Singlet

DMSO

6s

Ar

NH

NH2,

N-NH.

6.771-7.422

9.364

2.926

12.749

(q)(d)(sx)

Singlet

Singlet

Singlet

DMSO

7s

Ar

NH

NH2

N-NH

6.771-7.889

10.241

2.916

12.795

(q)(d)(sx)

Singlet

Singlet

Singlet

DMSO

8s

Ar

NH,

NH2

N-NH

6.77-7.422

9.361

1.926

12.775

(q)(sx)(d)

Singlet

Singlet

Singlet

DMSO

9s

Ar

NH

NH2

N-NH

6.771-8.612

9.709

2.597

12.757

(q)(d)(sx)

Singlet

Singlet

Singlet

DMSO

10s

Ar

NH

NH2

N-NH

N=CH

6.771-7.422

9.489

1.490

9.664

8.763,8.767

(q)(d)(sx)

Singlet

Singlet

Singlet

(s)(d)

DMSO

11s

Ar

NH

NH2

OH

N-NH

6.690-7.422

9.751

2.931

9.360

12.765

(d)(q)(sx)

Singlet

Singlet

Singlet

Singlet

DMSO

12s

Ar

NH

NH2

C-CH2

N-NH

6.771-7.422

11.127,9.517

1.000

3.723

10.313

(q)(sx)

Singlet

Singlet

Singlet

Singlet

DMSO

13s

Ar

NH

NH2

N-OH

N-NH

6.771-7.422

9.482

3.097

13.037

9.136

(q)(sx)

Singlet

Singlet

Singlet

Singlet

DMSO

14s

Ar

NH

NH2

CH2,CH3

N-NH

6.771-7.422

9.140

1.460

3.331,1.190

9.189

(q)(sx)

Singlet

Singlet

(q)(t)

Singlet

DMSO

δ(ppm)-chemical shift in parts per million:

3. Biological Activities

3.1 Anti-Microbial Method [12]: Cup Plate method by

Diffusion principle: In vitro antibacterial& antifungal

activities were examined for all the compounds synthesized

(1s-14s) against an assortment of two gram positive bacteria

Staphylococcus aureus ATCC 6538,Bacillus subtilis ATCC

6633 and two gram negative bacteria Escherichia coli ATCC

8739and Pseudomonas aeruginosa ATCC 9027&two fungal

strains of Aspergilus Niger MTCC 282 and Pencillium

notatum NCIM 742.The prepared media was inoculated to

perform the assay with required quantity of suspension of the

microorganism. The media was inoculated with microbial

suspension at a temperature between 400c -500cand

immediately inoculated media was poured in to the petri

dishes to give a depth of 3-4mm.The known concentrations of

test samples were prepared with diluting solvent methanol and

introduced in to the cavities prepared in the agar media. The

petri plates were left for diffusion (1-2 hours) at room

temperature or at 40c for some period of time for the test

concentrations to diffuse into the media. After that the plates

were incubated for 18 hours for anti-bacterial activity &72

hours for anti-fungal activity at room temperature. The

diameter or area of the circular inhibition zones were

measured.

~ 350 ~


Fig 1: Anti-fungal activity [27]

3.1.2 Anti-Oxidant [13]

Method: DPPH Free Radical Scavenging Assay: The

percentage of antioxidant activity (AA %) of each substance

was assessed by DPPH free radical assay. The samples were

reacted with the stable DPPH radical in an methanol solution.

The reaction mixture consisted of adding 1 mL of test samples

(1s-14s) in methanol, 1 mL of DPPH radical solution in

methanol. When DPPH reacts with an antioxidant compound,

which can donate hydrogen, it is reduced. The changes in

colour (from deep violet to light yellow) were read

[Absorbance (Abs)] at 517 nm after 100 min of reaction using

a UV-VIS spectrophotometer (DU 800; Beckman Coulter,

Fullerton, CA, USA). The mixture of methanol (1 mL) and

sample (Ascorbic acid) (1 mL) serve as blank. The control

solution was prepared by mixing methanol (1 mL) and DPPH

radical solution (1 mL). The scavenging activity percentage

(AA %) was determined by

% Inhibition = O.D of 𝑐𝑜𝑛𝑡𝑟𝑜𝑙−O.D of test

O.D of control

IC-50 values were determined from the % Inhibition and

were tabulated

Table 7: Anti-oxidant activity

Compound %inhibition IC 50

values 2.5µg/ml 5µg/ml 7.5µg/ml 10µg/ml

Std 37.39 66.08 53.04 25.21 3.93

1s 98.26 89.56 96.52 93.04 -

2s 87.82 91.30 91.30 91.30 -

3s 39.13 40.86 44.34 43.47 18.80

4s 46.95 40 45.21 48.69 17.7

5s 46.08 50.43 48.69 50.43 8.67

6s 48.69 42.60 34.78 50.43 -

7s 49.56 48.69 50.43 50.43 7.52

8s 43.47 51.30 51.30 47.82 9.17

9s 54.78 53.91 52.17 51.30 12.48

10s 50.43 53.91 49.56 53.04 -

11s 46.95 39.13 26.95 28.69 0.81

12s 52.17 49.56 53.04 53.91 0.028

13s 53.04 49.56 52.17 50.43 12.5

14s 37.39 14.78 4.34 0 -

~ 351 ~


4. Discussion

Synthesis of Schiff bases: The compounds synthesised by

conventional method and their characterisation by

spectroscopic methods, their physical parameters assessment

by online software Chemaxon [10] Cheminformatics software

reveal that the compounds possess very low solubility, highly

basic as their Pka values range from (8-9),log P (0-3.5)

provides basic information and support to the results obtained

practically. The spectroscopic features IR data reveal the

presence of NH2 (3700 Cm-1 to 3600 Cm-1), NH (3400 Cm-1 to

3500Cm-1), CH (2900-3100 Cm-1) stretching, C=O (1700 Cm-

1), C=N (1550-1490 Cm-1). Proton NMR reveals the presence

of two NH singlet’s between 10-12ppm, one singlet NH2 (4-

5ppm).

4.1 Antimicrobial activities

Cup plate diffusion method is preferred method for

antimicrobial studies.All the Schiff bases were moderately

active towards gram positive, gram negative and fungal

microorganisms as the inhibition zones were prominently

observed at concentrations above 250µg /ml of which the

compounds are more susceptible towards gram positive

organisms. Compounds 3s, 5s, 7s and 12s possess good

antibacterial and antifungal properties.

4.1.2 Antioxidant activity

The 2,2-diphenyl-1-picrylhydrazyl (DPPH) method is a

preferred method because it is fast, easy and reliable and does

not require a special reaction and device. Ascorbic acid

showed dose dependent antioxidant activity in DPPH assay.

Isatin compounds showed dose dependent free radical

scavenging activity in DPPH method. 5s, 7s, 8s, 11s, 12s

compounds showed higher % inhibition when compared with

other compounds.

In drug discovery, the development of hybrid molecules

through the combination of different pharmacophores leads to

compounds with interesting biological profiles. In this study,

synthesised isatin compounds (1s-14s) were selected and

screened antimicrobial and in vitro antioxidant activity. Isatin

Schiff bases showed dose dependent in-vitro antioxidant

activity in DPPH assay. 5s, 7s, 8s, 11s, 12s compounds

showed dose dependent antioxidant activity. The antioxidant

activity study provides a basis for further screening of other

pharmacological activities mainly anti-inflammatory etc.

5. Conclusion

A series of new novel 2-(3-oxo-dihydro-2H-indol-2-

ylidene)hydrazine carboxmide schiff base sderivatives were

prepared by conventional method and evaluated for their

antimicrobial, DPPH free radical scavenging assay for which

the mechanisms underlying this process remain to be fully

elucidated. It is intended that the results from these studies

will assist in elucidating their precise mechanism of action

and provide an approach for further optimization and

development to get new leads in the treatment of microbial

infections.

6. Acknowledgements The authors are thankful to the Siddhartha Academy for

General and Technical Education for providing necessary

facilities to carry out this research work.

7. References 1. Muhammad Aqeel Ashraf, Karamat Mahmood, Abdul

Wajid Synthesis, Characterization and Biological

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