Synthesis and Physico Chemical Studies of Some Chalcone and Their Derivatives as Potential Antimicrobial Agents.

 

Arun Kumar1, Vinita Gupta2, Sanchita Singh2, Y.K. Gupta3*

1Research Scholar, School of Applied Sciences Singhania University Pacheri Bari, Jhunjhunu (Raj.), India

2Department of Chemistry, Agra College, Agra, U.P, India

3Head Department of Chemistry, B K Birla Institute of Engineering and Technology, Pilani, Rajasthan, India

*Corresponding Author E-mail: ykgbkbiet123@gmail.com

 

ABSTRACT:

The Chalcone is an aromatic compound that forms the central core for various necessities of biological compounds. The Chalcone is synthesized by Claisen – Schmidt condensation of benzaldehyde derivatives with acetophenone derivatives in dilute ethanolic sodium hydroxide solution at room temperature. The structures of synthesized compounds were investigated by IR Spectroscopy, NMR Spectroscopy and Mass Spectrometry. The antimicrobial activity of the synthesized was evaluated by Filter Paper Disc diffusion Method. The compound 1b showed excellent activity against S. aureus at both concentration i.e. 500μg/ml and1000 μg/ml.

 

KEYWORDS:  Chalcone derivates, Antimicrobial agents

 

 

 


INTRODUCTION:

Heterocyclic compounds containing nitrogen and sulphur have significantly a lot of attention because of wide application of pharmacological activity. There is growing interest in the pharmacological potential of natural products is chalcones constitute a central group of natural products. Chemically, they consist of open chain flavanoids in which the two aromatic rings are joined by a three carbon α .β unsaturated carbonyl system The presence of a reactive α, β unsaturated keto function in chalcones is found to be accountable for their antimicrobial activity1 In recent years a variety of chalcones have been reviewed for their anticancer chemopreventive, cytotoxic and mutagenic as well as insecticidal, antiviral and enzyme inhibitory    properties2, 3.

 

A number of chalcones having alkoxy, hydroxy groups in various position have been reported to possess antibacterial4, antiulcer5, antifungal6, antioxidant7, vasodilatory8, antimitotic9, antimalarial10, antileshmanial11 and inhibition of chemical  ediators release, inhibition of leukotriene B412, inhibition of tyrosinase13,14 and inhibition of aldose reductase15 activities. Appreciation of these findings actuated us to synthesize chalcones as a possible model for antimicrobial agents. It should be noted that this scaffold provides substitution pattern on benzylidenacetophenones nucleus.

 

EXPERIMENTAL:

IR spectra were recorded by utilizing Perkin‐Elmer FTIR‐RX1 spectrophotometer. A 1HNMR spectrum was recorded by utilizing CDCl3 on Bruker Advance (400 MHz) and their chemical shifts are recorded in δ (parts per million) units with respect to tetramethylsilane (TMS) as internal standard. The melting points were recorded in open sulphuric acid or oil bath using thermometer and were uncorrected. Mass spectra were recorded on a Waters Q T of micro MS. All the reagents and solvents used were of analytical grade and were used as supplied. Progress of the reactions was observed utilizing TLC, performed on aluminum plates precoated with silica gel G, using chloroform: methanol (92:8) as the solvent systems and the spots were imagined by exposure to iodine vapors.

 

General Procedure

Chalcones were synthesized by Claisen Schmidt condensation reaction of appropriate substituted acetophenones and aldehydes by known literature scheme16. A mixture of benzaldehyde derivatives (0.01 mol) and acetophenone derivatives (0.01 mol) was dissolved in 10 ml rectified spirit in a 250 ml round bottom flask equipped with a magnetic stirrer. Then 10 ml NaOH solution (1g in 10ml H2O) was added drop wise to the reaction mixture on vigorous stirring for 30 minutes when solution became turbid. The reaction temperature was maintained between 20-25˚ C using a cold water bath on the magnetic stirrer. After vigorous stirring for 4-5 hours the reaction mixture was neutralized by 0.1-0.2N HCl, where by the precipitation happened. On separating off, the crude chalcones were dried in air and recrystallized by rectified spirit. The residue was purified on column chromatography (silica gel with 10% ethyl acetate in hexane) to afford pure chalcones (Scheme-1). The chemical profile of the compounds is as shown in Table-1.

 

(1a). 3(4methoxy phenyl) 1(4bromophenyl) 2propen1one

To a stirred mixture of p-bromoacetophenone (10mmol) and pmethoxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1a. Recrystalization from rectified spirit.. IR (nujol) cm-1: 1658 (>C=O in conjugation with C=C), 1596,1540 (>C=C< in conjugation with C=O), 722 (-Br);1HNMR (CDCl3),δ (ppm): 7.85(d, 2H, Ar 3', 5'H), 7.87 (d, 2H, Ar 2',6'H), 7.58(d,1Ha, J = 16 Hz, =CH), 7.61(d, 1Hb, J =16Hz, =CH), 6.92 (d, 2H, Ar 2",6"-H), 6.94(d,2H, Ar 3", 5"-H), 3.84(s,3H, Ar 4"-OCH3); Mass spectrum (EI,m/z): 318 (M+.+1) Exact mass of molecular ion m/z = 317.175, calculated for C16H13BrO2 : 317.177.

 

(1b). 3(4methoxy phenyl) 1(4iodophenyl) 2propen1one

To a stirred mixture of p-iodoacetophenone (10mmol) and pmethoxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1b. Recrystalization from rectified spirit.. IR (nujol) cm-1: 1656 (>C=O in conjugation with C=C), 1597,1541 (>C=C< in conjugation with C=O), 660(-I);1HNMR (CDCl3),δ (ppm): 7.72(d, 2H, Ar 3', 5'H), 7.83 (d, 2H, Ar 2',6'H), 7.58(d,1Ha, J = 16 Hz, =CH), 7.60(d, 1Hb, J =16Hz, =CH), 6.92 (d, 2H, Ar 2",6"-H), 6.94(d,2H, Ar 3", 5"-H), 3.85(s,3H, Ar 4"-OCH3);Mass spectrum (EI,m/z): 365 (M+.+1) Exact mass of molecular ion m/z = 364.175, calculated for C16H13IO2 : 364.178.

 

(1c). 3(4methoxy phenyl) 1(4methoxyphenyl) 2propen1one

To a stirred mixture of p-methoxyacetophenone (10mmol) and pmethoxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1c. Recrystalization from rectified spirit. IR (nujol) cm-1: 1655 (>C=O in conjugation with C=C), 1599,1528 (>C=C< in conjugation with C=O), 1017            (-OCH3);1HNMR (CDCl3),δ (ppm): 6.98(d, 2H, Ar 3', 5'H), 8.02 (d, 2H, Ar 2',6'H), 7.41(d,1Ha, J = 16 Hz, =CH), 7.76(d, 1Hb, J =16Hz, =CH), 7.61 (d, 2H, Ar 2",6"-H), 6.92(d,2H, Ar 3", 5"-H), 3.89(s,3H, Ar 4"         -OCH3); Mass spectrum (EI,m/z): 270 (M+.+2) Exact mass of molecular ion m/z = 268.303, calculated for C17H18O3 : 268.304.

 

(1d). 3(4methoxy phenyl) 1(4ethoxyphenyl) 2propen1one

To a stirred mixture of p-ethoxyacetophenone (10mmol) and pmethoxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1d. Recrystalization from rectified spirit.. IR (nujol) cm-1: 1654 (>C=O in conjugation with C=C), 1599,1526 (>C=C< in conjugation with C=O), 1048(-OC2H5), 1026(-OCH3);1HNMR (CDCl3),δ (ppm): 1.40-1.42(t, 3H, -CH3), 4.02‐4.06(q, 2H, -CH2), 6.95 (d, 2H, Ar 3', 5'H), 8.02 (d, 2H, Ar 2',6'H), 7.50(d,1Ha, J = 16 Hz, =CH), 7.76(d, 1Hb, J =16Hz, =CH), 7.61 (d, 2H, Ar 2",6"-H), 6.91 (d,2H, Ar 3", 5"-H), 3.83(s,3H,Ar"             -OCH3). Mass spectrum (EI, m/z): 283 (M+.+1) Exact mass of molecular ion m/z = 282.329, calculated for C18H18O3 : 282.330.

 

(1e). 3(4hydroxy phenyl) 1(4methoxyphenyl) 2propen1one

To a stirred mixture of p-methoxyacetophenone (10mmol) and phydroxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1e. Recrystallization from rectified spirit. IR (nujol) cm-1: 1640 (>C=O in conjugation with C=C), 1598,1528 (>C=C< in conjugation with C=O), 1020             (-OCH3), 3659(-OH); 1HNMR (CDCl3), δ (ppm): 3.87(s,3H,Ar-4'-OCH3), 6.89(d, 2H, Ar 3', 5'H), 7.94 (d, 2H, Ar 2',6'H), 7.51(d,1Ha, J = 16 Hz, =CH), 7.71(d, 1Hb, J =16Hz, =CH), 7.45 (d, 2H, Ar 2",6"-H), 6.96(d,2H, Ar3", 5"-H), 8.03(s,1H, Ar 4"-OH); Mass spectrum (EI,m/z): 255 (M+.+1) Exact mass of molecular ion m/z =254.278, calculated for C16H14O3 : 254.280.

 

(1f). 3(4hydroxyphenyl) 1(4chlorophenyl) 2propen1one

To a stirred mixture of p-chloroacetophenone (10mmol) and phydroxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1f. Recrystalization from rectified spirit; IR (nujol) cm-1: 1652 (>C=O in conjugation with C=C), 1592,1556 (>C=C< in conjugation with C=O), 754(-Cl),1390(-OH); 1HNMR (CDCl3),δ (ppm): 8.95(s,1H,-OH), 7.45(d, 2H, Ar 3', 5'H), 7.82 (d, 2H, Ar 2',6'H), 7.20(d,1Ha, J = 16 Hz, =CH), 7.86(d, 1Hb, J =16Hz, =CH), 7.52 (d, 2H, Ar 2",6"-H), 6.61(d,2H, Ar 3", 5"-H); Mass spectrum (EI,m/z): 259 (M+.+1) Exact mass of molecular ion m/z = 258.0445, calculated for C15H11ClO2 : 258.0447.

 

(1g). 3(4Hydroxyphenyl) 1(4bromophenyl) 2propen1one

To a stirred mixture of p-bromoacetophenone (10mmol) and phydroxy benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1g. Recrystalization from rectified spirit; IR ((nujol) cm-1: 1650 (>C=O in conjugation with C=C), 1590,1548 (>C=C< in conjugation with C=O), 654(-Br),1365(-OH); 1HNMR (CDCl3),δ (ppm): 8.92(s,1H,-OH), 7.55 (d, 2H, Ar 3', 5'H), 7.72 (d, 2H, Ar 2',6'H), 7.12(d,1Ha, J = 16 Hz, =CH), 7.76(d, 1Hb, J =16Hz, =CH), 7.42 (d, 2H, Ar 2",6"-H), 6.56(d,2H, Ar 3", 5"-H); Mass spectrum (EI,m/z): 303 (M+.+2) Exact mass of molecular ion m/z =301.9940, calculated for C15H11BrlO2 : 301.9942.

 

(1h). 3phenyl1 (4bromophenyl) 2propen1one

To a stirred mixture of p-bromoacetophenone (10mmol) and benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1h. Recrystalization from rectified spirit. IR (nujol) cm-1: 1652 (>C=O in conjugation with C=C), 1568,1517 (>C=C< in conjugation with C=O), 678(-Br);1HNMR (CDCl3),δ (ppm): 7.44(d, 2H, Ar 3', 5'H), 7.89 (d, 2H, Ar 2',6'H), 7.44(d,1Ha, J = 16 Hz, =CH), 7.78(d, 1Hb, J =16Hz, =CH), 7.61 (d, 2H, Ar 2",6"-H), 7.40(d,2H, Ar 3", 5"-H), 7.22(s,1H, Ar 4"-H); Mass spectrum (EI,m/z): 286 (M+.+1) Exact mass of molecular ion m/z = 285.997, calculated for C15H11BrO : 285.999

 

(1i). 3phenyl1 (4iodophenyl) 2propen1one

To a stirred mixture of p-iodoacetophenone (10mmol) and benzaldehyde (10mmol) in rectified spirit (10mL), sodium hydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1i. Recrystalization from rectified spirit. IR (nujol) cm-1: 1646 (>C=O in  onjugation with C=C), 1552,1498 (>C=C< in conjugation with C=O), 565(-I); 1HNMR (CDCl3),δ (ppm): 7.40(d, 2H, Ar 3', 5'H), 7.82 (d, 2H, Ar 2',6'H), 7.38(d,1Ha, J = 16 Hz, =CH), 7.74(d, 1Hb, J =16Hz, =CH), 7.53 (d, 2H, Ar 2",6"-H), 7.35(d,2H, Ar 3", 5"-H), 7.18(s,1H, Ar 4"-H); Mass spectrum (EI,m/z): 334 (M+.+1) Exact mass of molecular ion m/z = 333.983, calculated for C15H11ClO : 333.985.

 

(1j). 3phenyl1 (4ethoxyphenyl)2propen1one

To a stirred mixture of p-ethoxyacetophenone (10mmol) andbenzaldehyde (10mmol) in rectified spirit (10mL), sodiumhydroxide (10.0 mL) was added drop wise and treated as in the general procedure to give 1j.Recrystalization from rectified spirit. IR (nujol) cm-1: 1648(>C=O in conjugation with C=C), 1576, 1534 (>C=C< in conjugation with C=O), 1048 (-OC2H5); 1HNMR(CDCl3), δ (ppm): 1.39-1.43(t, 3H, -CH3), 4.03-4.08(q, 2H, -CH2), 6.95(d, 2H, Ar 3', 5'H), 8.02 (d, 2H, Ar 2',6'H), 7.51(d,1Ha, J = 16 Hz, =CH),7.76(d, 1Hb, J =16Hz, =CH), 7.61 (d, 2H, Ar 2",6"-H), 7.36-7.39 (m,3H,Ar 3",4", 5"-H); Mass spectrum (EI, m/z): 253(M+.+1) Exact mass of molecular ion m/z = 252.1150, calculated for C17H16O2:252.1151.

 

Antibacterial activity

Antimicrobial activities of all synthesized compounds were dictated by disc diffusion method17. All human pathogenic bacteria viz Pseudomonas aeruginosa (1688), Staphylococcus aureus (737), were procured. The agar medium was purchased from Hi media Laboratories Ltd., Mumbai, India. Preparation of nutrient broth, subculture, base layer medium, agar medium and peptone water was done as per the standard procedure. Discs measuring 6.25 mm in diameter were punched from Whatman filter paper No.1.Stock solutions of synthesized compounds diluted in dimethyl sulphoxide (1% DMSO) to give final concentration of 500μg/ml and 1000 μg/ml. A reference standard for both gram positive and gram negative bacteria was made by dissolving accurately weighed quantity of chloramphenicol (500 and 1000 μg/mL, respectively) in sterile distilled water, separately. The incubation was carried out at 37ºC for 24h. All the experiments were carried out in triplicate. Simultaneously, controls were maintained by employing 0.1 mL of dimethyl sulfoxide which did not reveal any inhibition. Zones of inhibition produced by each compound were measured in mm. The results of antibacterial studies are given in Table-2.

 

RESULTS AND DISCUSSION:

The structures of synthesized compounds were confirmed by IR, 1HNMR and Mass spectral analysis. The synthesized compounds were confirmed by IR spectral data showing sharp bands in the range between 1630-1660 cm‐1 indicated the presence of C=O group. Compounds (1a-1h) were also confirmed by 1HNMR spectral analysis. Inspection of the 1HNMR spectra suggested that the chalcones were geometrically pure and configured Trans (JHa-Hb = 16 Hz. The outcomes revealed that majority of the synthesized compounds indicated varying degrees of inhibition against Gram positive bacteria shown in Table 2. The 1b showed excellent activity against S. aureus at both concentration i.e. 500μg/ml and1000 μg/ml. The compounds1b, 1i , 1d, 1h and 1g ,1f have shown good to moderate activity against S aureus at both concentration i.e. 500μg/ml and 1000 μg/ml. Three of the chalcones with antistaphylococcal activity (1c, 1eand1j) gave no inhibitory zones most likely because of their low dispersion potential into agar media.

 

At long last, no activity was observed for compounds against P. aeruginosa, a Gram negative organism. It is widely known that Gram positive and negative organisms have significantly different membrane compositions and architecture18 which would explain the selective activity of the present compounds against Gram positive S. aureus.

 


 

Table 1: Physical constants of the synthesized compounds

Compd. code

R1

R2

Molecular formula

M. Wt

Yield %

MP(°C)

1a

OCH3

Br

C16H13BrO2

317.17

87

197-198

1b

OCH3

I

C16H13IO2

364.18

81

199-201

1c

OCH3

OCH3

C17H18O3

268.30

69

175-177

1d

OC2H5

OCH3

C18H18O3

282.33

64

186-188

1e

OH

OCH3

C16H14O3

254.28

49

238-240

1f

OH

Cl

C15H11ClO2

258.04

33

235-237

1g

OH

BR

C15H11BrO2

301.99

31

265268

1h

H

Br

C15H11BrO

285.99

89

155-157

1i

H

I

C15H11 IO

333.98

88

154-156

1j

H

-OC2H5

C17H16O2

252.11

85

140-143

 

Table 2: Antimicrobial activity of the synthesized compounds

Compounds

Antibacterial activity(%inhibition)

Staphylococcus aureus (737)

Pseudomonas aeruginosa (1688)

500μg/mL

1000μg/mL

500μg/mL

1000μg/mL

1a

25.0

34.7

-

 

1b

29.9

40.2

-

-

1c

-

-

-

-

1d

23.9

33.5

-

-

1e

-

-

-

-

1f

21.5

32.2

-

-

1g

22.7

32.7

-

-

1h

23.0

33.4

-

-

1i

24.6

34.8

-

-

1j

-

-

-

-

Chloramphenicol

42.2

55.2

63.8

78.8

DMSO

1.5

-

1.2

-

 

Scheme- 1: Scheme of synthesis of compounds

 

 


REFERENCES:

1      Gupta Y.K., Agarwal S.C., “Physical characterization of some complexes of nitrogen donor compounds”,  International Journal of Chemical Engineering, Vol. 4, Issue 2,2011 pp 147-158.

2      Gupta Yogesh Kumar, Gupta Vinita, Singh Sanchita “Synthesis, Characterization and Antimicrobial activity of Pyrimidine based derivatives”. Journal of Pharmacy Research, (Elsevier) Vol. 07, No. 06,2013 pp 491-495.

3      Yu DC, Panfilova LV, Boreko EI. Synthesis and antiviral activity of unsaturated ketones of thiopene series. Pharm. Chem, 16:1982, 103105.

4      Liu XL, Xu YJ, Go ML. Functionalized chalcones with basic functionalities have antibacterial activity against drug sensitive Staphylococcus aureus. European Journal of Medicinal Chemistry, 43:2008, 6811687.

5      Gupta Vinita, Singh Sanchita and Gupta Y.K.* “Synthesis and Antimicrobial Activity of some Salicylaldehyde Schiff bases of 2-aminopyridine”. Research Journal of Chemical Sciences, Vol. 03, Issue 09,2013 pp 26-29.

6      Lahtchev KL, Batovska DI, Parushev SP,Ubiyvovk VM, Sibirny AA. Antifungal activity of chalcones: A mechanistic study using various yeast strains. European Journal of Medicinal Chemistry, 2008; 43: 22202228.

7      GuptaY.K.,Agarwal S.C., "Synthesis and antimicrobial activity of new 4-thiazolidinone derivatives containing 2-amino-6-ethoxybenzothiazole", Asian Journal of Research in Chemistry, Vol. 4, No 12, 2011pp 1245-1252.

8      Dong X, Chen J, Jiang C, Liu T, Hu Y. Design, synthesis, and biological evaluation of prenylated chalcones as vasorelaxantagents. Arch Pharm (Weinheim), 2009; 342(7): 42832.

9      Gupta Vinita, Singh Sanchita, Gupta Y.K. Synthesis and Antimicrobial Activities of Zn(II) Complex of 2,5-diamino-1,3,4-thiadiazole”. Research Journal of Sciences and   Technology. 2013; 5 (4): 462-465.

10    Ram VJ, Saxena A, Srivastava S and Chandra S. Oxygen at dchalcones and bischalcones as potential antimalarial agents. Bioorganic and Medicinal Chemistry Letters 2000; 10: 21592161.

11    Liu M, Wilairat P, Croft SL, Choo AL and Goa ML. Structure–Activity Relationships of antileishmanial and antimalarial Chalcones. Bioorganic and Medicinal Chemistry, 2003; 11: 2729–2738.

12    Gupta Y.K, Gupta Vinita, Singh Sanchita “Synthesis, characterization and antibacterial activity of some 4-Thiazolidinones derivatives”. Asian Journal of Research in Chemistry, Vol. 05, No 9, 2012 pp 1155-1158.

13    Khatib S, Nerya O, Musa R, Shmuel M, Tamir S, Vaya J. Chalcones as potent tyrosinase inhibitors: the importance of a2,4substituted resorcinol moiety. Bioorganic and Medicinal Chemistry, 2005; 13: 433441.

14    Te SC. An Updated Review of Tyrosinase Inhibitors Int. J. Mol. Sci, 2009; 10: 24402475

15    Gupta Y.K., Agarwal S.C., “Study of Antimicrobial activities of Schiff bases”, Journal of ultra chemistry, Vol. 7, No 3,2011 pp 493-502.

16    Ahmed MG, Romman UKR, Ahmed SM, Akhter K. Synthesis and Correlation of Spectral Properties of Some Substituted 1, 3Diphenyl2Propen1Ones. Bangladesh J. Sci. Ind. Res, 2007; 42(1): 4552.

17    Gupta Y.K., Agarwal S.C., Sharma Dilip “Synthesis and biological activities of 2-Methyl-4-N-2-cyanoethyl-N-substituted benzaldehydes and their derivatives”, Asian Journal of Research in Chemistry, Vol. 5, No 2,2012 pp 245-247.

18    Papo N, Shai Y. A novel lytic peptide composed of dlamino acids selectively kills cancer cells. Peptides 2003; 24:1693 1703.

 

 

 

 

Received on 18.03.2017             Modified on 06.04.2017

Accepted on 25.04.2017           © RJPT All right reserved

Research J. Pharm. and Tech. 2017; 10(4): 1155-1159.

DOI: 10.5958/0974-360X.2017.00208.6