Catecholthioether Derivatives: Preliminary Study of in-Vitro Antimicrobial and Antioxidant Activities

Abstract

In this research, synthesis, antimicrobial and antioxidant activities of a series of catecholthioethers having benzoxazole and tetrazole moieties are described. Antimicrobial activity was evaluated by minimum inhibitory concentration (MIC) assay. The synthesized compounds were tested in vitro against three Gram-positive bacteria including Staphylococcus aureus (clinical isolated), Staphylococcus aureus ATCC 25922, Enterococcus faecium (clinical isolated), and two Gram-negative bacteria including Klebsiella pneumoniae (clinical isolated) and Pseudomonas aeruginosa 27853 and the yeast Candida albicans in comparison with control drugs. Microbiological results indicated that the synthesized compounds possessed a broad spectrum of activity against the tested microorganisms at MIC values between 4-256 m mg/ml. This shows compounds having tetrazole moiety were the most active against Gram-negative strains, whereas compounds having benzoxazole moiety were more active against Gram-positive ones. Also both of them showed significant antifungal activity against Candida albicans and had lower activity than the compared control drugs (Sulfamethoxazole and Fluconazole). The antioxidant activity was assessed using two methods, including, 1,1-biphenyl-2-picrylhydrazyl (DPPH) radical scavenging, and reducing power assays. Some of the catecholthioether derivatives showed antioxidant activity more than Trolox and butylated hydroxyanisole (BHA) as reference antioxidants.

Electrooxidation Is a Promising Approach to Functionalization of Pyrazole-Type Compounds

“…Developing this direction, the opportunity of transformation of the SCN group into the SH group [ 94 , 123 ] was shown, which opens the way to thiols as promising nucleophiles for C–H functionalization (e.g., see [ 133 , 134 , 135 ]). Hydrolysis with HCl was the most effective (yields of thiols 7g , 16g , 18g were 61–77%), while the use of chemical reductants or strong acids (LiAlH 4 , NaBH 4 , Zn in AcOH, HClO 4 , H 2 SO 4 ) was ineffective.…”

Tetrazolium Compounds: Synthesis and Applications in Medicine

“…The IC 50 of compound 122 that the best for antioxidant activity among tetrazolium compounds, with a value of 0.17. Furthermore, 122 could inhibit in vitro growth of Candida albicans having the same inhibitory activity as fluconazole (MIC value 4 mg/mL) [ 98 ]. Singh et al synthesized several regioisomeric tetrazolylindole derivatives and screened them for their ER binding affinity, agonist (estrogenic), antagonist (antiestrogenic) and anti-implantation activities.…”

Chemo and regioselective serendipitous electrochemically initiated spirocyclization of caffeic acid esters with barbituric acid derivatives

“…More importantly, in these protocols the electrons are used as the only reagents in synthetic organic reactions [17]. Considering above facts and in continuation of our research in the field of green electrochemical synthesis of organic structures [18][19][20][21], herein we report an experimentally clean and feasible procedure for the synthesis of a new series of spiro derivatives of various caffeates and barbituric acid derivatives.…”