Overview on Developed Synthesis Methods of Triazepane Heterocycles

Radical N2-Retention Cyclizations of Aryl Diazoniums: Access to 7/8/9-Membered Heterocycles

We report herein a modular approach to synthesizing diverse functionalized 7/8/9-membered poly-N-containing heterocycles via oxidative radical N2-retention cyclizations of allylic aryl diazonium salts using CF3SO2Na as a CF3 radical source. A range of trifluoromethylated benzotriazepines, benzotriazocines, and benzotriazonines were obtained in moderate to good yields. This transition-metal-free protocol demonstrates atom economy, safe conditions, broad functional group tolerance, and availability of readily accessible reagents.

Microwave-assisted Synthesis of Novel Pyrazole Derivatives and their Biological Evaluation as Anti-Bacterial Agents

AIMS AND OBJECTIVES

Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol.

MATERIALS AND METHODS

The structural features of the synthesized compounds were characterized by melting point, FT-IR, ¹H, ¹³C NMR and elemental analysis.

RESULTS

The antibacterial activities of the synthesized pyrazoles were evaluated against three gram-positive bacteria, such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium.

CONCLUSION

All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain, and none of them demonstrated antibacterial activity against E. coli.