Synthesis, Characterization and Antimicrobial Activity of Diphenylamino Isoxazoline Derivatives

 

Hitesh V. Shahare¹*, Rakesh D. Amrutkar²

¹Department of  Pharmaceutical Chemistry, SNJBs Shriman Sureshdada Jain College of Pharmacy, Chandwad, Nashik-423001 (M.S.) India.

²KBH College of Pharmacy, Camp Road, Malegaon, (M.S.) India.

 

ABSTRACT:

Rationale: Tremendous increase in development of resistance to the antimicrobials has created alarming situation for researchers and clinicians. Method: An attempt has been made to develop a series of isoxazoline derivatives by using Claisen-Schmidt condensation and Michael addition. All the newly synthesized compounds were characterized by TLC, IR and ¹HNMR spectroscopy. These isoxazoline compounds H1 to H4 were screened for their antibacterial activity against Gram positive bacteria (S. aureus and B. subtilis) and Gram negative bacteria (E. coli and P. aeurogenosa) using Disc diffusion method. Results: Amongst all, compound H2 and H4 showed significant antimicrobial activity against the all bacteria which was comparable to standard Ciprofloxacin. Conclusion: Synthesized Isoxazoline derivatives exhibits a good antimicrobial activity and can be further explored to confirm their suitability at clinical level.

 

 

 

1. INTRODUCTION:

Derivatives of Isoxazole have played a crucial role in the history of heterocyclic chemistry and been used extensively important pharmacophores and synthons in the field of organic chemistry. Owing to their versatile

Chemotherapeutic importance, a significant amount of research effort has been focused on these nuclei.^1-2

 

Isoxazole derivatives exhibit various biological activities such as, Anticonvulsant, Anticancer, Anthelmintics Anti-inflammatory, Fungicidal, Hypoglycemic, Muscle relaxant and Antimicrobials.^3-5

 

 

Tremendous increase in development of resistance to the antimicrobials has created alarming situation for researchers and clinicians. In view of this, Isoxazole based derivatives has been focused to synthesize and screened for their potential effect in search of better antimicrobials.^6-8

 

 

Target Molecule

Fig.1. General Structure of Isoxazoline Derivative

 

2. MATERIAL AND METHODS:

The entire chemicals were purchased from Sigma Aldrich Chemical Company (USA) and solvents were used after purification by distillation.

Table 1: Details of common chemicals used in reaction

Sr.No.	Character	Hydroxylamine hydrochloride	Sodium hydroxide	Ethanol	Benzaldehyde
1.	Mol wt	69.49	40	46.07	106
2.	Mol formula	H4NOCl	NaOH	C2H5OH	C7H6O
3.	Solubility	Water, alcohol, ethanol, methanol	Water, alcohol, methanol, and glycerol	Water, fatty oil, organic solvent	Miscible with ethanol, ether, oils
4.	Melting point	1510 C	318OC	--	_
5.	Boiling point	_	_	78.50C	1790C

 

2. 1] Synthesis of substituted isoxazoline derivatives:

The classical synthesis of the title compounds involves the base-catalyzed condensation of substituted aromatic ketone and substituted aldehydes to give α, β-unsaturated ketones (Chalcones), which on cyclization with hydroxylamine hydrochloride in alkaline medium give the corresponding isoxazoline derivatives.^9-10

 

General Procedure:

Step I: Novel N, N-diphenyl amino, 3- substituted phenyl-2, 3-propenamide were prepared by Claisen-Schimidt reaction.

 

Step II: A mixture of N, N-diphenyl amino, 3- substituted phenyl-2, 3-propenamide (0.03mole) in ethanol (50ml), hydroxylamine hydrochloride (0.03 mole) and sodium hydroxide (0.4 gm) were added in round bottomed flask. The reaction mixture was refluxed for 8 hr. The resulting mixture was poured into ice water. The resulting solid was filtered, dried and recrystallized from ethanol.

 

2. 2] Characterization of synthesized compounds:

Amino isoxazoline derivatives have been synthesized successfully and were characterized by their melting point, TLC, IR and ¹H NMR.

 

All melting points were measured with a capillary apparatus and are uncor­rected. The purity of synthesized compound was checked by performing TLC. The solvent system used for TLC was Acetone + Ethyl acetate. [5:5] The IR spectra were recorded in KBr on a Jasco FTIR 5300 spectrophotometer and ¹H NMR spectra were recorded on a Bruker DPX-300 MHz spectrometer by using TMS as an internal standard.

 

2.3] Biological Evaluation:

Method:

The synthesized compounds of the series were screened for their antimicrobial activity against the growth of four bacteria by following disc diffusion method. Sterile filter paper disc of 6 mm were used. The bacteria used are Escherichia coli, Staphylococcus aureus, Pseudomonas aurogenosa and Bacillus subtilis. The 10 mg/ml was prepared in Dimethyl formamide. The activities of the compound were compared with standard antibacterial drug (Ciprofloxacin) under the same conditions.^11-12

 

Ciprofloxacin [Standard]: 0.3mg/ml.

Broad spectrum; active against Gram positive, but more active against Gram negative bacteria.

3. RESULT AND DISCUSSION:

Novel isoxazoline derivative were synthesized by cyclization of substituted chalcone derivatives in the presence of hydroxylamine hydrochloride (Figure 1).

 

3. 1] Synthesis of substituted isoxazoline derivatives:

The newer amino isoxazoline derivatives were synthesized in the laboratory successfully with the great yields.

 

Table 2: Observation of synthesized amino isoxazoline derivatives

Comp. No.	Mol. Formula	Mol. Wt	Reaction Time [Hrs]	Melting Point [0C]	% Yield	Rf value
H1	C21H15N2OCl	345	8	125	63.52	0.80
H2	C21H15N3O3	357	8.2	128	74.19	0.84
H3	C22H18N2O3	358	8.1	132	69.40	0.85
H4	C31H22N2O	438	8	129	73.27	0.80

 

3. 2] Characterization of synthesized compounds:

Melting point:

The melting point of each synthesized compound was taken by using capillary apparatus and is uncor­rected.

(Table 2)

 

Thin Layer chromatography (TLC):

The R_f value of each synthesized compound has been calculated and purity has been checked after recrystallization. (Table 2)

 

 

Fig.2. TLC observation of synthesized compound

Where, A and B: Reactant and C: Product

 

 

Fig. 3. Zone of inhibition

Spectral analysis (IR and ¹H NMR):

Table 3: Spectral data of synthesized amino isoxazoline derivatives

Compound Code	IR Spectra (cm-1)	1H NMR Spectra  (δ ppm)
H1	1673(C=N), 3317 (Ar-H), 1423 (C-N), 1510 (C=C), 1340 (C-O-N), 835 (C- Cl)	6.99-8.1 (m, 14H, Ar), 3.64 (d, 2H, CH2 isoxazoline), 5.96 (s, 1H, CH isoxazoline
H2	1662(C=N), 3321 (Ar-H), 1419 (C-N), 1506 (C=C), 1339 (C-O-N), 1558 (NO2)	7.1-8 (m, 14H, Ar), 3.59 (d, 2H, CH2 isoxazoline), 4.28 (s, 1H, CH isoxazoline
H3	1646 (C=N), 3327 (Ar-H), 1402 (C-N), 1522 (C=C), 1364 (C-O-N),	7.1-8.2 (m, 14H, Ar), 3.91 (d, 2H, CH2 isoxazoline), 5.17 (s, 1H, CH isoxazoline 3.2 (s, 3H, OCH3)
H4	1688(C=N), 3303 (Ar-H), 1429 (C-N), 1518 (C=C), 1327 (C-O-N),1252 (OCH3), 1314 (C-OH)	7.0-8.1(m, 14H, Ar), 4.0 (d, 2H, CH2 isoxazoline), 5.2 (s, 1H, CH isoxazoline 3.1 (s, 3H, OCH3), 10.1 (s, 1H, OH)

 

Table 4: Antimicrobial activity of synthesized amino isoxazoline derivatives

Comp. No.	Substituent’s (R)	Escherichia coli	Staphylococcus Aureus	Pseudomonas aurogenosa	Bacillus subtilis
H1		_	2.1	2.4	2.8
H2		2.4	2.3	2.9	2.9
H3		2.7	2.0	_	2.5
H4		3.4	2.4	3.1	3.7
Standard	Ciprofloxacin	4.6	3	3.7	4.2
Solvent	Dimethyl formamide	_	_	_	_

 

3. 3] Biological Evaluation:

Novel synthesized amino isoxazoline derivatives were evaluated for their antimicrobial activity and they showed better activity. (Table 4)

 

4. ACKNOWLEDGEMENT:

The authors are grateful to the authorities of SNJBs Shriman Sureshdada Jain College of Pharmacy, Chandwad, Nashik (M.S.) for the facilities and motivation to research work.

 

5. CONCLUSION:

The present research work involves synthesis of novel Isoxazoline derivative to explore their antimicrobial activity. Compound H4exhibited highest antimicrobial activity. Hence, it is concluded that there is ample scope for further study in developing these as good lead compounds for the treatment of bacterial strain.

 

6. REFERENCES:

1.        Krishna Veni Chikkula, Raja S. Isoxazole–A Potent Pharmacophore. International Journal of Pharmacy and Pharmaceutical Sciences. 2017; 9(7): 13-24.

2.        Dravyakar BR, Kawade DP, Khedekar PB, Busari KP. Design and synthesis of some new diphenylaminoisoxazolines as potent anti-inflammatory agent. Indian Journal of Chemistry. 2008; 47B: 1559-1567.

3.        Shivkumar B and Nargund L. V. G. Synthesis, characterization and anti-inflammatory activity of some isoxazoline derivatives. Indian J Heterocyclic Chem. 1998; 8: 27.

4.        Puttaswamy N, Pavan Kumar GS, Vigneshwaran V, Prabhakar BT. Synthesis and biological evaluation of salicylic acid conjugated isoxazoline analogues on immune cell proliferation and angiogenesis. European Journal of Medicinal Chemistry. 2016; 114: 153-61.

5.        Kumar A, Fernandes J, Kumar P. Synthesis and biological evaluation of some novel isoxazoline derivatives of carbostyril. WJPPS. 2014; 3(2): 1267-1277.

6.        Gollapalli Naga Raju, Suresh PV, Nadendla RR, Katta A. Synthesis, characterization and antimicrobial evaluation of isoxazole Derivatives. 2015; Der Pharma Chemica; 7(6): 346-352.

7.        Pawar Sudhir, Chavan Rajashree  Bhosale Ashok. Synthesis and Biological Evaluation of Mannich Bases of Isoxazoline Derivatives as Novel Anti-Microbial Agents. E-Journal of Chemistry. 2012; 9(4):1760-1772.

8.        Bhimwa Rajeev, Sharma AK, Jain  Ankit. Synthesis, Characterization and In-Vitro Antimicrobial Evaluation of Some Novel Isoxazoline Derivatives. Journal of Advanced Pharmacy Education and Research. 2011; 1(5): 251-258.

9.        Badadhe PV, Chavan NM, Mandhane PG, Joshi RS, Nagargoje DR, Gill CH. Synthesis and characterization of some novel isoxazolines and pyrazolines as potent antimicrobial agents. Indian J Chem (Sec B). 2011; 50B: 879-84.

10.     Rani Manju, Sharma Shivani, Chauhan Rajani, Sharma Swapnil. Synthesis, Characterization and Antibacterial Evaluation of Some Azole Derivatives.  Indian Journal of Pharmaceutical Education and Research.2017; 51(4): 650-655.

11.     Prabhakar V, Babu KS, Ravindranath LK. Synthesis and anti-microbial studies of novel isoxazoline derivatives bearing thieno [2, 3-d] pyrimidine as a core unit. Heterocyclic Letters. 2017; 7(2): 475-492.

12.     Uno H, Kurokawa M, Masuda Y and Nishimuura H, Synthesis and antimicrobial studies of some novel isoxazoline derivatives. J Med. Chem.1979; 22: 180.

 

 

 

 

 

Received on 21.06.2018          Accepted on 15.07.2018        

© Asian Pharma Press All Right Reserved

Asian J. Pharm. Res. 2018; 8(3):  148-150.

DOI: 10.5958/2231-5691.2018.00026.6