SYNTHESIS, SPECTRAL CHARACTERIZATION OF DIBENZOFURAN-1,3-THIAZOLE CARBOXAMIDE DERIVATIVES AND EVALUATED FOR ANTI-INFLAMMATORY POTENTIAL

Objective: The objective of the paper is synthesis and characterization of dibenzofuran-1,3-thiazole carboxamide derivatives and screened for anti-inflammatory potential

Material and methods: The present work was aimed to synthesis some dibenzofuran-1,3 thiazole carboxamide derivatives by four step reactions with the substitution of various substituted benzylamine under suitable catalyst. The compound 1 (S-((4-chlorodibenzo[b,d]furan-1-yl)methyl)thiohydroxylamine), Compound 2 (ethyl 2-(4-chlorodibenzo[b,d]furan-1-yl)-5-methylthiazole-4-carboxylate), compound 3 (2-(4-chlorodibenzo[b,d]furan-1-yl)-5-methylthiazole-4-carboxylic acid) and compound 4 (N-benzyl-2-(4-chlorodibenzo[b,d]furan-1-yl)-5-methyl thiazole-4-carboxamide) were prepared. The Compound 4 coded as compound TC-1 to TC-14. In this four steps process total 12 compounds have been synthesized and evaluated for the anti-inflammatory potential by protein denaturation assay.

Result and Discussion:  The IR spectrum of the compounds has shown the characteristics peak (cm^-1) of N-H at 3412; C=C-H at 3470; C=O at 1735; C=C at 1624–1446; C-N at 1015; p-substitution at 792; C-F at 1102; C-Cl at 855; C-Br at 1015; N-O at 1356; N=O at 1558. The 1HNMR spectra of Final compounds (TC-1 to TC-12) depicted the peak at 2.90 (3H, CH₃); 4.64 - 4.65 (2H, CH₂); 7.05-7.10 (2H, Ar-H); 7.35 (1H, Ar-H); 7.33 – 7.39 (4H, Ar-H); 7.45 (1H, Ar-H); 7.48 - 7.50 (1H, Ar-H); 7.62 - 7.63 (1H, Ar-H); 7.90 - 7.92 (1H, Ar-H); 8.38 – 8.40 (1H, N-H). Compound TC-1, mass spectrum has shown peak at m/z = 450.85, which matches the chemical formula C₂₄H₁₆ClFN₂O₂S. The protein denaturation assay of synthesized compound stated that most active compound are TC-1, TC-2, TC-3, TC-4 and TC-5 and compounds TC-7 & TC-9 has shown the mild activity and compound TC-6, TC-8, TC-10, TC-11 and TC-12 has shown modest activity. 

Conclusion: The Cl, Br, I, NO₂ and F substitution enhance the activity when it attached to 4-position of the thiazole ring with addition of electronegative atom also enhance the anti-inflammatory potential of compounds.

Keywords: Anti-inflammatory, thiazole, protein denaturation assay, dibenzofuran