Synthesis Of Novel 1,3,4-Oxadiazole Derivative as Anti-Inflammatory Agents

   ¹³CNMR:

Figure .No. 5 ¹³CNMR (COMP A&B ).

Figure No-7 HRBC Method

Compound		Distance travel (in CM)	R.F Value
Compound A	Solvent	6.4	---
	Benzaldehyde	4.5	0.6
	A	5.4	0.8
Compound    B	Solvent	6	---
	Phenylhydrazine Hcl	4.4	0.7
	B	5	0.7

Figure No 9 .Comp A         FigureNo-10Comp B

RESULTS AND DISCUSSION

The present investigation successfully achieved the synthesis of two novel oxadiazole derivatives designated as Compound A and Compound B. Both compounds were obtained as crystalline solids with satisfactory yields and good purity after recrystallization.

The percentage yield obtained for Compound A (84%) was higher than that of Compound B (71%), indicating that the multistep synthetic route employed for Compound A provided better product recovery. Physicochemical characterization revealed that both compounds were stable solids possessing distinct melting point ranges. Compound A exhibited a melting point of 198–202°C, while Compound B showed a slightly higher melting point of 210–214°C, suggesting stronger intermolecular interactions within its crystal lattice.

Qualitative chemical tests further supported the formation of the desired compounds. Positive responses in bromine water and ferric chloride tests indicated the presence of unsaturated and aromatic functionalities. The observed reactions confirmed the incorporation of heterocyclic and substituted aromatic moieties within the synthesized molecules.

FT-IR spectral analysis provided important evidence regarding the structural features of the compounds. Compound A displayed characteristic absorption bands corresponding to N–H stretching, aromatic C–H stretching, aromatic C=C vibrations, and C–N/C–O linkages. Compound B showed similar aromatic absorptions along with a prominent carbonyl stretching band, indicating the presence of additional functional group contributions. These spectral features were consistent with the proposed molecular structures.

The ¹H NMR spectra demonstrated signals attributable to aromatic protons and heterocyclic substituents. Compound A exhibited a singlet corresponding to the azomethine proton along with multiplets arising from aromatic hydrogens. Compound B showed characteristic NH proton resonances and aromatic proton signals, confirming the presence of the phenylhydrazino substituent. The chemical shift values were in good agreement with the expected proton environments.

Further structural confirmation was obtained through ¹³C NMR spectroscopy. Downfield carbon resonances corresponding to oxadiazole ring carbons were observed in both compounds. Aromatic carbon signals appeared within the expected chemical shift range, supporting successful cyclization and formation of the target heterocyclic framework.

Mass spectrometric analysis revealed molecular ion peaks and characteristic fragmentation patterns consistent with substituted 1,3,4-oxadiazole derivatives. The fragmentation profiles provided additional evidence for the molecular architecture of the synthesized compounds. The observed mass-to-charge ratios supported the proposed structures and confirmed the successful synthesis of both target molecules.

Overall, the combined physicochemical and spectral studies conclusively established the formation of the desired oxadiazole derivatives. The presence of biologically relevant functional groups and the stability of the synthesized compounds suggest their potential usefulness for future pharmacological evaluation, particularly in anti-inflammatory drug discovery programs.^{[14’15’18]}

CONCLUSION

The present study successfully synthesized and characterized two novel 1,3,4-oxadiazole derivatives, namely 2-phenyl-5-(benzylideneamino)-1,3,4-oxadiazole and 2-phenyl-5-(phenylhydrazino)-1,3,4-oxadiazole. The synthesized compounds were obtained in good yields and exhibited satisfactory physicochemical properties. Structural elucidation using FT-IR, ¹H NMR, ¹³C NMR, and mass spectrometry confirmed the successful formation of the oxadiazole ring system and the proposed molecular structures. The spectral data demonstrated the presence of characteristic functional groups and aromatic heterocyclic frameworks. These findings indicate that the developed synthetic methods are effective for the preparation of oxadiazole-based molecules. Considering the established pharmacological significance of 1,3,4-oxadiazole derivatives, the synthesized compounds may represent promising candidates for further biological screening and optimization as potential anti-inflammatory agents.^{[1’11’17’16]}

REFERENCES

1. Husain A., Ajmal M. Synthesis of novel 1,3,4-oxadiazole derivatives and biological properties.
2. Chawla G. et al. Oxadiazole scaffold in anti-inflammatory activity.
3. Biju C.R. et al. Microwave-assisted synthesis of oxadiazoles.
4. Pathak A. et al. Novel oxadiazole derivatives as anti-inflammatory agents.
5. Singhai A., Gupta M.K. Oxadiazole derivatives as NSAID alternatives
6. Mishra R. et al. 1,3,4-Oxadiazole derivatives: synthesis and pharmacological activity.International Journal of Pharmaceutical Sciences, 2011.
7. Borg S. et al. Design, synthesis and biological evaluation of oxadiazole derivatives as anti-inflammatory agents.Bioorganic & Medicinal Chemistry, 2009.
8. Rollas S. &Küçükgüzel ?. G.. Biological activities of hydrazone derivatives.Molecules, 2007.
9. Akhtar T. et al. Synthesis and anti-inflammatory evaluation of substituted oxadiazoles.European Journal of Medicinal Chemistry, 2010.
10. Holla B. S. et al. Synthesis of oxadiazole derivatives and their biological evaluation.Indian Journal of Chemistry, 2006.
11. Kumar D. et al. Synthesis and biological evaluation of oxadiazole derivatives as anti-inflammatory agents.Bioorganic & Medicinal Chemistry Letters, 2008.
12. Sharma P. C. et al. Oxadiazole: a biologically important scaffold.Journal of Enzyme Inhibition and Medicinal Chemistry, 2010.
13. Patel N. B. et al. Synthesis and antimicrobial/anti-inflammatory activities of oxadiazoles.Arkivoc, 2012.
14. Maslat A. O. et al. Synthesis and biological activity of some heterocyclic compounds.Polish Journal of Pharmacology, 2002.
15. Abdel-Wahab B. F. et al. Synthesis and anti-inflammatory activity of heterocycles containing oxadiazole moiety.European Journal of Chemistry, 2012.
16. Rane R. A. et al. Synthesis and evaluation of oxadiazole derivatives as anti-inflammatory agents.European Journal of Medicinal Chemistry, 2012.
17. Gursoy A. &Terzioglu N.. Synthesis and isolation of new oxadiazole derivatives.Turkish Journal of Chemistry, 2005.
18. Singh A. K. et al. Recent advances in 1,3,4-oxadiazole chemistry.International Journal of Research in Pharmaceutical Sciences, 2013.
19. Zhang H. Z. et al. Design and synthesis of novel oxadiazole derivatives as anti-inflammatory agents.Bioorganic & Medicinal Chemistry Letters, 2009