Design and Synthesis of Some New Benzimidazole Containing Pyrazoles and Pyrazolyl Thiazoles as Potential Antimicrobial Agents

Abstract

A new class of bis heterocycles‐benzimidazolyl pyrazoles were prepared from the Michael acceptor (E)‐3‐(1H‐benzimidazol‐2‐yl)‐1‐aryl‐prop‐2‐en‐1‐one. The thiamide group was exploited to develop thiazole ring on treatment with p‐fluorophenacyl bromide to get tris heterocycles. All the lead compounds were tested for antimicrobial activity. The compound 7d having nitro substituent on the aromatic ring showed greater antimicrobial activity particularly against Pseudomonas aeruginosa and Penicillium chrysogenum.

In Vitro Antimicrobial Evaluation, Single-Point Resistance Study, and Radiosterilization of Novel Pyrazole Incorporating Thiazol-4-one/Thiophene Derivatives as Dual DNA Gyrase and DHFR Inhibitors against MDR Pathogens

“…35 Furthermore, 1,3-diphenyl-1H-pyrazole-4-carbaldehyde (2a), 1-phenyl-3-(p-tolyl)-1H-pyrazole-4-carbaldehyde (2b), 37 2-cyano-N- (1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)acetamide ( 9), 41,56 The MIC of the target compounds (having inhibition zones > 9 mm) was then determined using the broth microdilution method. 58 Two-fold serial dilutions of the tested compounds were prepared to give a concentration range 0.125−128 μg/mL. Sterile test tubes containing the target compounds were placed in sterile TSB medium for bacteria and sterile SDB for the fungi.…”

“…In addition, the effect of gamma radiation on the antimicrobial activity of the active target was studied against the different bacterial and fungal isolates by determination of their MICs values after exposure to radiation, according to the CLSI protocol. 58 In the tests, microbial culture with a standardized O.D. was used, and the assay was run in triplicate.…”

“…The plates were then incubated with bacteria and fungi at 37 °C for 24 h and at 28 °C for 48 h, respectively. The lowest concentration at which no visible growth was observed was noted as the MBC or MFC . In addition, MBC/MIC and MFC/MIC ratios were determined, and if the tested agent yields an MBC or MFC/MIC ratio ≤ 4, then it is considered to be -cidal, but if it yields a ratio > 4, then it will be -static…”

Development in the Synthesis of Bioactive Thiazole-Based Heterocyclic Hybrids Utilizing Phenacyl Bromide

“…The method exhibits versatility across a wide range of applications and circumvents the formation of undesirable byproducts such as thiocyanatoketone and 3,5dimethylpyrazole, while mitigating issues associated with low yields, protracted reaction times, expensive catalysts, and the use of potentially hazardous solvents (Scheme 54). 120 have communicated the synthesis of a series of innovative benzimidazoles featuring pyrazolyl-thiazole moieties 132a−132g. This synthesis involved the utilization of pyrazole derivatives 131 and phenacyl bromide 90, employing a refluxing procedure conducted on a water bath in ethanol for 5 h, yielding products in good to moderate yields.…”

“…Benzimidazole Hybrids. Bakthavatchala Reddy and group 120 have communicated the synthesis of a series of innovative benzimidazoles featuring pyrazolyl-thiazole moieties 132a−132g. This synthesis involved the utilization of pyrazole derivatives 131 and phenacyl bromide 90, employing a refluxing procedure conducted on a water bath in ethanol for 5 h, yielding products in good to moderate yields.…”