Recent progress on pyrazole scaffold-based antimycobacterial agents

Telescoped continuous flow generation of a library of highly substituted 3-thio-1,2,4-triazoles

An integrated continuous flow process for the synthesis of 3-thio-1,2,4-triazoles is reported. A small library of 18 compounds was prepared in just 48 minutes of residence time in moderate to excellent yields.

Synthesis and antimicrobial studies of novel derivatives of 4-(4-formyl-3-phenyl-1H-pyrazol-1-yl)benzoic acid as potent anti-Acinetobacter baumannii agents

Microbial resistance to antibiotics is a global concern. The World Health Organization (WHO) has identified antimicrobial resistance as one the three greatest threats for human beings in the 21st century. Without urgent and coordinated action, the world is moving toward a post-antibiotic era, in which normal infections or minor injuries may become fatal. In an effort to find new agents, we report the synthesis and antimicrobial activities of 40 novel 1,3-diphenyl pyrazole derivatives. These compounds have shown zones of growth inhibition up to 85mm against Acinetobacter baumannii. We tested the active compounds against this Gram-negative bacterium in minimum inhibitory concentration (MIC) tests and found activity with concentration as low as 4μg/mL.

Antitubercular activity of 1,2,3-triazolyl fatty acid derivatives

A collection of 1,2,3-triazoles unsaturated fatty acid mimics were efficiently synthesized by click chemistry. The 1,4-disubstituted analogs prepared covered different alkyl chain lengths and triazole positions. The compounds were subsequently tested against Mycobacterium tuberculosis, being most of them active with some of the analogs displaying activity at micromolar concentration. The most potent member of the series has the triazole moiety on the C-2 position with a carbon chain of eight or ten carbon atoms. The 1,5-isomers of the most active analog were significantly less active than the original isomer. The activity of the selected hit was assayed on several clinical MTB multi-drug resistant strains providing the same MIC.

The first computational study for the oxidative aromatization of pyrazolines and 1,4-dihydropyridines using 1,2,4-triazolinediones: an anomeric-based oxidation

The oxidative aromatization of 1,3,5-trisubstituted pyrazolines and 1,4-dihydropyridines using 1,2,4-triazolinediones as oxidizing agents was studied. It is confirmed that the “anomeric-based oxidation” passes through a concerted oxidation via hydrogen abstraction–addition.

Theoretical and experimental investigation of the polyeletrophilic β-enamino diketone: straightforward and highly regioselective synthesis of 1,4,5-trisubstituted pyrazoles and pyrazolo[3,4-d]pyridazinones

A highly efficient regioselective synthesis of 1,4,5-trisubstituted pyrazoles and pyrazolo[3,4-d]pyridazinones from enamino diketone along with a theoretical and experimental study of the chemical reactivity enamino diketone.

Synthesis of tetra-substituted 5-trifluoromethylpyrazoles via sequential halogenation/palladium-catalyzed C–C and C–N cross-coupling

The assembly of tetra-substituted 5-trifluoromethylpyrazoles is presented, involving palladium-catalyzed Negishi or Buchwald–Hartwig cross-couplings to install carbon or nitrogen-based 4-substituents.