Use of transesterified 1,3-diketoesters in the synthesis of trisubstituted pyrazoles and their biological screening

Abstract

ABSTRACT. Starting from 2-acetylbenzofuran derivatives 1a-d, methyl/ethyl 4-substituted/unsubstituted benzofuran-2-yl)-2,4-dioxobutanoate 2a-d and 3a-d have been synthesized by Claisen's condensation reaction with diethyloxalate. The transesterified product, 1,3-diketoester 2a-d on condensation with phenyl hydrazine undergo cyclization to afford the corresponding methyl 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carboxylate 4a-d, which upon further condensation with hydrazine hydrate yielded 5-(substituted/unsubstituted benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazide 5a-d. The structures of the newly synthesized compounds 2a-d, 3a-d, 4a-d and 5a-d were characterized by their elemental analysis and spectral studies such as IR, 1 H NMR, 13 C NMR and MS. All the synthesized compounds were screened for their antimicrobial activity. Most of the synthesized compounds showed high sensitivity against the selected bacteria and fungi at various concentrations.

Synthesis, Antimicrobial Evaluation and Docking Study of Some Pyrazole Bearing [1, 2,4]Triazolo[3, 4‐b][1, 3,4]thiadiazole Derivatives

“…In 13 C NMR spectra signals appeared at δ 151.00 and 165.56 indicates 3 rd and 5 th Carbon of triazole moiety respectively, other signals were appeared at the presupposed chemical shifts. As per the general methods reported, compound ( 5 ) was reacted with substituted benzoic/pyridinyl acids in phosphorous oxychloride at reflux temperature for 8–10 h to gives 6‐substituted‐3‐[5‐(3‐fluoro‐4‐methoxy‐phenyl)‐1 H ‐pyrazol‐3‐yl]‐[1, 2,4]triazolo[3, 4‐b][1, 3,4]thiadiazole derivatives ( 6 a‐l ). IR spectra with absence of NH 2 and SH stretching vibrations and absence of NH 2 and SH protons in NMR suggesting formation of 6‐substituted‐3‐[5‐(3‐fluoro‐4‐methoxy‐phenyl)‐1 H ‐pyrazol‐3‐yl]‐[1, 2,4]triazolo[3, 4‐b][1, 3,4]thiadiazole derivatives ( 6 a‐l ).…”

Synthesis and Antibacterial Screening of 4-Arylidene-5-oxo-imidazoles having Carboxamide Linkage with 5-(benzofuran-2-yl)-1-phenylpyrazole Moiety

“…Analytical and spectral data of 3a was in full agreement with proposed structure. 5-(H/Br benzofuran-2-yl)-1-phenyl-1H-pyrazole-3-carbohydrazides (1a-b) 24 and 4-(arylidene)-2-phenyloxazol-5(4H)-ones (2a-g) were synthesized in quantitative yields by adopting the literature method 25 and their confirmation were done on the basis of m.p. determination.…”

Benzofuran as a promising scaffold for the synthesis of antimicrobial and antibreast cancer agents: A review

“…[ 16 ] Several benzofuran derivatives have been prepared and introduced as antibacterial agents. [ 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 ] Renuka et al . [ 17 ] designed and synthesized a series of substituted benzofurans as DNA gyrase B inhibitors of Mycobacterium tuberculosis (MTB).…”