Synthesis and Antimicrobial Activities of Novel 2‐[substituted‐1H‐pyrazol‐4‐yl] Benzothiazoles, Benzoxazoles, and Benzimidazoles

Abstract

MIC, minimal inhibitory concentration values; bacterial strain, E. coli and S. aureus; fungal strain, C. albicans and A. niger; solvent used, DMSO; standard: bacterial strain, streptomycin 125 mg/mL; fungal strains, fluconazole 125 mg/mL. 1352V. S. Padalkar, B. N.

Recent Developments Towards Synthesis of (Het)arylbenzimidazoles

“…44 The use of (het)arenecarbaldehydes and methyl (het)aryl ketones in this reaction makes it possible to obtain 2-(het)aryl-substituted benzimidazoles. The synthesis of 2-arylbenzimidazoles 4 (Table 2) and 2-hetarylbenzimidazoles 5 (Table 3) by the reaction of arenecarbaldehydes 30 and hetarenecarbaldehydes 31 with 1,2-DABs 1 was successfully carried out in the following solvents and systems: EtOH, 45 EtOH in the presence of NH 4 Cl, 27b Et 3 N, 10b PCl 3 , 46 DMF, 10a,47 DMF/H 2 O, 20 DMF in the presence of p-TsOH, 48 EtOH, 9a,b,49 DMF 9c,d,h,18,50 in the presence of Na 2 S 2 O 5 , MeOH, 51 50% aq MeOH, 52 in the molecular sieves system (3Å)-MeOH, 14 THF, 53 50% aq THF, 27c DMSO, 24a,54 H 2 O, 55 and MeCN. 56 In some cases, various oxidizing agents such as Oxone, 20 UHP (urea hydrogen peroxide)/I 2 , 54 55 MIL-101(Cr)-NO 2 , 56a and Fe 3 O 4 @SiO 2 -ZnCl 2 nanoparticles 45g were used for the synthesis of benzimidazoles.…”

Synthesis, Crystal Structure, Antifungal Activity, and Docking Study of Difluoromethyl Pyrazole Derivatives

“…In the recent years, lots of succinate dehydrogenase inhibitors contain pyrazole motif , such as penthiopyrad, sedaxane, pydiflumetofen, bixafen, isopyrazam, and pyrapropoyne fluxapyroxad. Chemists are very interested in pyrazole because of its unique biological activity, such as antimicrobial , DPPH radical scavenging , anticancer , antifungal , anti‐inflammatory , nematicidal , and cholinesterases inhibitory activities. On the other hand, urea structure also is an important skeleton in bioactive molecules.…”

Unravelling the synthetic and therapeutic aspects of five, six and fused heterocycles using Vilsmeier–Haack reagent

“…In 2016, Padalkar and co-workers 45 synthesized few 3-aryl-4-formyl pyrazoles from substituted hydrazones using V. H. reagent (DMF-POCl 3 ) by stirring the reaction mixture at room temperature for 8 hours, in good to excellent yield. Further, 2-[substituted-1 H -pyrazol-4-yl]benzothiazoles, benzimidazoles and benzoxazoles were produced using these formyl pyrazoles and diagnosed for anti-bacterial and anti-fungal efficacy.…”