INTRODUCTION:

1, 3, 4-Oxadiazole is a five-membered heterocyclic ring containing two nitrogen atoms and one oxygen atom. This framework is highly valuable in medicinal chemistry because of its strong chemical stability, planar structure, and its ability to function as a bioisostere—often replacing amide or ester groups in drug molecules^1,2. Derivatives of 1,3,4-oxadiazole are known to exhibit a wide range of biological activities, including antimicrobial, anti-inflammatory, anticancer, antiviral, and antidiabetic effects^3,4. The ring system can be synthesized through different methods, most commonly by cyclization of diacylhydrazines or oxidative cyclization of N-acylhydrazones⁵. Additionally, the nitrogen and oxygen atoms in the ring serve as hydrogen-bond acceptors, enabling strong interactions with biological targets and contributing to the scaffold’s importance in drug design⁶.

Microwave-assisted synthesis has become a preferred approach for preparing 1, 3, 4-oxadiazole derivatives because it significantly accelerates reactions and improves yields. Under microwave heating, acyl hydrazides or diacylhydrazines rapidly cyclize to form the oxadiazole ring within minutes instead of hours, increasing efficiency⁷. Microwave irradiation also enhances the action of reagents such as POCl₃, polyphosphoric acid, and various acidic catalysts, resulting in cleaner products with fewer impurities⁸. Several protocols even allow solvent-free conditions, making the method eco-friendlier and reducing purification requirements^9,10. Overall, microwave-assisted techniques offer higher yields, shorter reaction times, and simpler work-up procedures when compared with conventional heating, supporting their use in oxadiazole synthesis^7–11.

Characterization of 1,3,4-oxadiazole derivatives typically includes melting-point determination, which serves as a key indicator of purity and structural confirmation, often reflected by a sharp and reproducible temperature range. Thin Layer Chromatography (TLC) is also routinely used during reaction monitoring and final purity evaluation, usually carried out on silica gel plates visualized under UV light, where RF values help verify completion of cyclization¹². Furthermore, molecular docking studies are widely performed to predict the binding affinity, stability, and interaction patterns of oxadiazole derivatives with biological targets. These computational tools frequently involve antimicrobial targets such as CYP51, DNA gyrase, or DHFR, and provide insight into hydrogen-bonding interactions, hydrophobic contacts, and the overall orientation of the molecule within active sites^13,14.

1,3,4-Oxadiazole derivatives exhibit broad antimicrobial potential—including antibacterial, antifungal, antitubercular, and antibiofilm activities—making them important candidates for drug discovery. The oxadiazole ring acts as both a bioisostere and a planar aromatic linker, improving interactions with microbial targets such as DNA gyrase, DHFR, and CYP51, and contributing to the disruption of key cellular pathways including cell-wall or membrane biosynthesis. Numerous derivatives demonstrate strong activity against Gram-positive and Gram-negative bacteria, Mycobacterium species, and microbial biofilms. Their antimicrobial potency is strongly influenced by substituent patterns such as aryl or heteroaryl groups, electron-withdrawing substituents, and polar hydrogen-bond accepting groups, which modulate both activity and spectrum^15–17.

MATERIALS AND METHODS:

a) Reaction Scheme:¹⁸

Where,

R = R1 =

A = P-amino Benzoic Acid. x = Benzaldehydes.

b = Benzoic Acid. y= 3Nitrobenzaldehydes.

c = 3, 5 Dinitrobenzoic Acid.

b) Procedure:¹⁸

Step 1: Synthesis of Methyl Carboxylate:

Substituted methyl carboxylate was prepared by adding 0.01mol of substituted carboxylic acid in 10ml methanol. Further reaction is processed by irradiating the mixture in microwave for 5min at 340 watt by adding few drops of H2so4, as catalyst. After completion of reaction solid was formed which used for next step for the preparation of substituted Carbohydrazide.

Step 2: Synthesis of Substituted Carbohydrazide:

The mixture of above compound 0.01mol and 2ml 99% hydrazine hydrate was subjected in microwave for 10 min at 340watt. AFTER Completion of reaction TLC was checked and solid precipitate was dried and recrystallized with methanol.

Step 3: Synthesis of 5 Substituted 1, 3, 4 oxadiazole 2 amine:

The mixture of above substituted carohydrazide 0.01mol in 10ml methanol and add phosphorus pentachloride 0.01mol this reaction mixture was irradiated in microwave for 10 min at 340watt, after reaction checked by TLC. The solution was cooled and neutralized with NaHC03.

Step 4: Synthesis of N-(1, 3, 4 –oxadiazolidine-2yl) formamide:

Synthesis of substituted Eqivalent amounts each respective 5 substituted 1, 3, 4-oxadiazole 2 amine 0.01mol, Acetic acid (2ml), and methanol (3ml), aldehydes (2ml) for 20-25minutes in 340 watts. After reaching air temperature the remaining solution was slowly stirred as it was put onto ice. Examine TLC and melting point for confirmation of product.

c) Molecular Docking:

Molecular docking through SwissDock is widely used to predict the antibacterial potential of 1,3,4-oxadiazole derivatives by evaluating how strongly these molecules bind to key bacterial enzymes. After submitting optimized ligand and protein structures, SwissDock generates ranked binding poses using the EADock DSS scoring system, where lower FullFitness and ΔG values indicate stronger predicted antibacterial activity^19,20. Analysis of top-ranked poses often reveals hydrogen bonding and hydrophobic interactions with essential bacterial targets such as DNA gyrase, DHFR, and enoyl-ACP reductase—interactions known to correlate with antibacterial efficacy^21,22. Previous studies on oxadiazole derivatives have shown that strong binding scores and stable interactions with these targets reliably predict their in vitro antimicrobial potency²³.

d) Pharmacological Activity (Antibacterial Activity):

Antibacterial activity refers to the ability of a substance to stop bacteria from growing or to kill them. It is an important property studied in medicine, microbiology, and drug discovery because bacteria are responsible for many infectious diseases²⁴.

Definition: The capacity of a compound (natural or synthetic) to inhibit bacterial growth or destroy bacterial cells²⁴.

Mechanism: Antibacterial agents work by targeting unique features of bacterial cells, such as their cell wall, protein synthesis machinery, DNA replication, or metabolic pathways^25-27.

Procedure:

The pharmacological activity was evaluated using the agar well diffusion method. Nutrient agar (5g) was weighed and dissolved in 100mL of distilled water by boiling, then cooled, wrapped, and sterilized in an autoclave for 1 hour 30 minutes. A culture test tube was prepared by adding 1 mL of distilled water and dissolving the culture media in it. Under aseptic conditions between two burners, the sterilized agar was mixed with the culture media and poured into sterile Petri plates. The plates were then incubated overnight to allow solidification. After solidification, wells were carefully made in the agar, and the test solutions were added—each product was prepared by dissolving 0.4mg of the compound in 10mL of ethanol, while ciprofloxacin served as the standard drug. The plates were incubated again overnight, and the antibacterial activity was assessed by observing the zone of inhibition around each well^25-27.

RESULT AND DISCUSSION:

Table No. 1: Physiochemical data of 5 substituted 1, 3,4oxadiazolidine-2ylformamide by microwave methods

Sr. No.	Compound Code	Structure	Molecular Formula	Molecular Weight (g/mol)	Melting Point(⁰C)	Percentage Yield (%)	Rf Value
1	6ax		C17H12N4O5	382	120-124	90	0.74
2	6ay		C17H12N4O5	337	130-134	82	0.80
3	6bx		C17H8N6O11	352	122-128	88	0.66
4	6by		C17H10N4O7	397	120-126	92	0.82
5	6cx		C17H9N5O9	427	165.5-167.5	88	0.76
6	6cy		C17H8N6O11	472	240-245	94	0.77

Table No. 2: Molecular Docking Result

Sr. No.	Compound code	Calculated Affinity
1	6ax	-6.317
2	6ay	-7.667
3	6bx	-6.008
4	6by	-5.780
5	6cx	-7.383
6	6cy	-6.420

Fig. No. 1.: Result of docking study


Fig. No. 2.: Protein ligand	Fig. No. 3.: Protein ligand

Fig. No. 4.: Ligand

Table No. 3: Antibacterial Activity Result-

Organism	Sample	Zone of inhibition	Activity level
Escherichia coli	Test Sample (6ay)	17 mm	++(Moderate Activity)
Staphylococcus aureus	Test Sample (6ay)	24 mm	+++(Strong Activity_
Positive control (Std. antibiotic) (Ciprofloxacin)	–	>25	++++(Very Strong Activity)
Negative Control	–	0 mm	–

Fig. No. 5: Antibacterial activity

Table No. 4: Meaning of qualitative symbol

Symbol	Interpretation	Approx. Zone Diameter(mm)
-	No inhibition	0-5 mm
+	Weak Activity	6-12 mm
++	Moderate Activity	13-18mm
+++	Strong Activity	19-25 mm
++++	Very Strong Activity	>25 mm

REFERENCES:

1. Luczynski M, Kudelko A. Synthesis and biological activity of 1, 3, 4-oxadiazoles used in medicine and agriculture. Applied Sciences. 2022 Apr 8; 12(8): 3756.

2. Sharma U, Kumar R, Mazumder A, Salahuddin, Kukreti N, Mishra R, Chaitanya MV. Substrate‐based synthetic strategies and biological activities of 1, 3, 4‐oxadiazole: A review. Chemical Biology and Drug Design. 2024 Jun; 103(6): e14552.

3. Lata S, Choudhary L, Bharwal A, Pandit A, Abbot V. A Comprehensive Review: Synthesis and Pharmacological Activities of 1, 3, 4-Oxadiazole Hybrid Scaffolds. Medicinal Chemistry. 2025 Jan 23.

4. Glomb T, Świątek P. Antimicrobial activity of 1, 3, 4-oxadiazole derivatives. International Journal of Molecular Sciences. 2021 Jun 29; 22(13): 6979.

5. De Oliveira CS, Lira BF, Barbosa-Filo JM, Lorenzo JG, de Athayde-Filho PF. Synthetic approaches and pharmacological activity of 1, 3, 4-oxadiazoles: a review of the literature from 2000–2012. Molecules. 2012 Aug 27; 17(9):10192-231.

6. Wang JJ, Sun W, Jia WD, Bian M, Yu LJ. Research progress on the synthesis and pharmacology of 1, 3, 4-oxadiazole and 1, 2, 4-oxadiazole derivatives: a mini review. Journal of Enzyme Inhibition and Medicinal Chemistry. 2022 Dec 31; 37(1): 2304-19.

7. Shahzad SA, Yar M, Khan ZA, Khan IU, Naqvi SA, Mahmood N, Khan KM. Microwave-assisted solvent free efficient synthesis of 1, 3, 4-oxadiazole-2 (3H)-thiones and their potent in vitro urease inhibition activity. European Journal of Chemistry. 2012 Jun 30; 3(2): 143-6.

8. GORJIzADEH MA, Afshari M, NAzARI SI. Microwave-assisted one-step synthesis of 2, 5-disubstituted-1, 3, 4-oxadiazoles using 1, 4-bis (triphenylphosphonium)-2-butene peroxodisulfate. Orient. J. Chem. 2013; 29(4): 1627-30.

9. Kumar S, Yadav S, Jadon S, Kumar V, Khedr AM, Gupta KC. A facile microwave assisted synthesis and spectral analysis of 2-amino-5-substituted phenyl-1, 3, 4-oxadiazoles. Oriental Journal of Chemistry. 2012; 28(4): 1845.

10. Khan KM, Rani M, Perveen S, Haider SM, Choudhary MI, Voelter W. Microwave-assisted synthesis of 2, 5-disubstituted-1, 3, 4-oxadiazoles. Letters in Organic Chemistry. 2004 Jan 1; 1(1): 50-2.

11. Srinivasa MG, Paithankar JG, Birangal SR, Pai A, Pai V, Deshpande SN, Revanasiddappa BC. Novel hybrids of thiazolidinedione-1, 3, 4-oxadiazole derivatives: synthesis, molecular docking, MD simulations, ADMET study, in vitro, and in vivo anti-diabetic assessment. RSC advances. 2023; 13(3): 1567-79.

12. Kolageri S, Hemanth S, Parit M. In-silico ADME prediction and molecular docking study of novel benzimidazole-1, 3, 4-oxadiazole derivatives as CYP51 inhibitors for antimicrobial activity. Journal of Applied Pharmaceutical Research. 2022 Sep 30; 10(3): 28-38.

13. Glomb T, Świątek P. Antimicrobial activity of 1, 3, 4-oxadiazole derivatives. International Journal of Molecular Sciences. 2021 Jun 29; 22(13): 6979.

14. Zheng Z, Liu Q, Kim W, Tharmalingam N, Fuchs BB, Mylonakis E. Antimicrobial activity of 1, 3, 4-oxadiazole derivatives against planktonic cells and biofilm of Staphylococcus aureus. Future Medicinal Chemistry. 2018 Feb 1; 10(3): 283-96.

15. Al-Wahaibi LH, Mohamed AA, Tawfik SS, Hassan HM, El-Emam AA. 1, 3, 4-Oxadiazole N-Mannich bases: synthesis, antimicrobial, and anti-proliferative activities. Molecules. 2021 Apr 7; 26(8): 2110.

16. Al-Wahaibi LH, Mohamed AA, Tawfik SS, Hassan HM, El-Emam AA. 1, 3, 4-Oxadiazole N-Mannich bases: synthesis, antimicrobial, and anti-proliferative activities. Molecules. 2021 Apr 7; 26(8): 2110.

17. Rasras AJ, El-Naggar M, Safwat NA, Al-Qawasmeh RA. Cholyl 1, 3, 4-oxadiazole hybrid compounds: design, synthesis and antimicrobial assessment. Beilstein Journal of Organic Chemistry. 2022 May 31; 18(1): 631-8.

18. Jadhav AS, Yadav AR, Mohite SK. Synthesis and In-silico Study of Novel 1, 3, 4-Oxadiazole Derivatives: A Biologically active Scaffolds which induce Anti-tubercular activity by targeting Pteridine Reductase and Dihydrofolate Reductase. Int J Sci Res Sci Technol. 2022 Nov: 337-45.

19. Grosdidier A, Zoete V, Michielin O. SwissDock, a protein-small molecule docking web service based on EADock DSS. Nucleic acids research. 2011 May 28; 39(suppl_2): W270-7.

20. Bugnon M, Röhrig UF, Goullieux M, Perez MA, Daina A, Michielin O, Zoete V. SwissDock 2024: major enhancements for small-molecule docking with Attracting Cavities and AutoDock Vina. Nucleic Acids Research. 2024 Jul 5; 52(W1): W324-32.

21. Kolageri S, Hemanth S, Parit M. In-silico ADME prediction and molecular docking study of novel benzimidazole-1, 3, 4-oxadiazole derivatives as CYP51 inhibitors for antimicrobial activity. Journal of Applied Pharmaceutical Research. 2022 Sep 30; 10(3): 28-38.

22. Batool M, Tajammal A, Farhat F, Verpoort F, Khattak ZA, Shahid M, Ahmad HA, Munawar MA, Zia-ur-Rehman M, Asim Raza Basra M. Molecular docking, computational, and antithrombotic studies of novel 1, 3, 4-oxadiazole derivatives. International Journal of Molecular Sciences. 2018 Nov 15; 19(11): 3606.

23. Rane RA, Gutte SD, Sahu NU. Synthesis and evaluation of novel 1, 3, 4-oxadiazole derivatives of marine bromopyrrole alkaloids as antimicrobial agent. Bioorganic and Medicinal Chemistry Letters. 2012 Oct 15; 22(20): 6429-32.

24. Sanyal B. Physico-chemical factors in bacterial growth and some ecological implications. The University of Manchester (United Kingdom); 1969.

25. Walsh C. Antibiotics: Actions, origins, Resistance. 2003.

26. Kohanski MA, Dwyer DJ, Collins JJ. How antibiotics kill bacteria: from targets to networks. Nature Reviews Microbiology. 2010 Jun; 8(6): 423-35.

27. Gupta V, Kashaw SK, Jatav V, Mishra P. Synthesis and antimicrobial activity of some new 3–[5-(4-substituted) phenyl-1, 3, 4-oxadiazole-2yl]-2-styrylquinazoline-4 (3H)-ones. Medicinal Chemistry Research. 2008 Jun; 17(2): 205-11.

Received on 17.12.2025 Revised on 10.01.2026

Accepted on 31.01.2026 Published on 25.04.2026

Available online from April 28, 2026

Research J. Science and Tech. 2026; 18(2):145-150.

DOI: 10.52711/2349-2988.2026.00020

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Creative Commons License.