Design, synthesis, molecular docking, and dynamic studies of novel thiazole derivatives incorporating benzimidazole moiety and assessment as antibacterial agents

A general and sustainable approach for the synthesis of benzimidazole-thiazole compounds via an efficient, one-pot, domino, pseudo-four-component reaction using 5-amino-2-mercaptobenzimidazole, aralkyl halides, ammonium thiocyanate, and substituted α-bromo-acetophenones in glacial acetic acid at ambient temperature to give final compounds (4a-p) in good yields in shorter time. The spectral data of synthesized compounds were evaluated by analytical and spectral techniques (IR, ¹H-NMR, ¹³C-NMR, and ESI-HRMS). Further, some of the synthesized compounds were screened for their in-vitro antibacterial activity studies using the agar well diffusion method against Gram-positive Streptococcus pneumoniae (2451) bacteria and Gram-negative Proteous mirabilis (2081) bacteria. Based on the MIC results, it was observed that the most active compounds 4b, 4e, 4f, and 4k show promising antibacterial activity with the zone of inhibition values of 2.85 cm 2.75 cm, 3.6 cm, and 3.3 cm against both Gram-negative and positive bacteria cell lines, respectively. Further, we have also insight into the molecular simulation studies, based on the binding results, compound 4i showed stable binding interactions with streptomycin drug with the active site of the gyrase protein (PDB ID: 1KIJ). The structure-activity relationship (SAR) studies of all the title scaffolds were also established. The antibacterial activity, molecular docking studies, and molecular dynamic simulations of the title compounds suggested that these are promising antibacterial active skeletons.

New class of fused [3,2-b][1,2,4]triazolothiazoles for targeting glioma in vitro

Glioma is aggressive malignant tumor with limited therapeutic interventions. Herein we report the synthesis of fused bicyclic 1,2,4-triazolothiazoles by a one-pot multi-component approach and their activity against C6 rat and LN18 human glioma cell lines. The target compounds 2-(6-phenylthiazolo[3,2-b][1,2,4]triazol-2-yl) isoindoline-1,3-diones and (E)-1-phenyl-N-(6-phenylthiazolo[3,2-b][1,2,4]triazol-2-yl) methanimines were obtained by the reaction of 5-amino-4H-1,2,4-triazole-3-thiol with substituted phenacyl bromide, phthalic anhydride, and different aromatic aldehydes in EtOH/HCl under reflux conditions. In C6 rat glioma cell lines, compounds 4g and 6i showed good cytotoxic activity with IC₅₀ values of 8.09 and 8.74 μM, respectively, resulting in G1 and G2-M phase arrest of the cell cycle and activation of apoptosis by modulating phosphorylation of ERK and AKT pathway.

Recent Developments in Multi-component Synthesis of Lawsone Derivatives

BACKGROUND

2-Hydroxy-1,4-Naphthoquinone (HNQ; Lawsone) is one of the most useful and the simplest naturally occurring naphthoquinones and has stimulated a resurgence of interest in the past decades due to a wide range of pharmacological activities.

INTRODUCTION AND METHODS

This activity has led to the unusually large emphasis being placed on the design of more efficient multi-component reactions (MCRs) in the synthesis of bioactive lawsone derivatives.

RESULTS AND CONCLUSION

This review highlights the recent developments in multi-component synthesis of biologically relevant naphthoquinone linked and fused heterocyclic derivatives carried out from 2015 till now.

Discovery of ( ±)-3-(1H-pyrazol-1-yl)-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4] thiadiazine derivatives with promising in vitro anticoronavirus and antitumoral activity

A new series of ( ±)-(3-(3,5-dimethyl-1H-pyrazol-1-yl)-6-phenyl-6,7-dihydro-5H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-7-yl)(phenyl)methanones were efficiently synthesized starting from 4-amino-5-hydrazinyl-4H-1,2,4-triazole-3-thiol 1, acetyl acetone 2, various aromatic and heterocyclic aldehydes 3 and phenacyl bromides 4. All the newly synthesized compounds were tested for their antiviral and antitumoral activity. It was shown that subtle structural variations on the phenyl moiety allowed to tune biological properties toward antiviral or antitumoral activity. Mode-of-action studies revealed that the antitumoral activity was due to inhibition of tubulin polymerization.

Polyethylene glycol (PEG-400) promoted one-pot, five-component synthesis of (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)-4-oxothiazol-5(4H)-ylidene)acetates

A facile, inexpensive and eco-friendly synthesis of functionalised (E)-ethyl2-(2-((E)-2-(1-(4-methyl-2-(phenylamino)thiazol-5yl)ethylidene)hydrazinyl)14-oxothiazol-5(4H)-ylidene)acetates has been developed via one-pot five-component approach. The title compounds were synthesized by the reaction of anilines, 3-chloropentane-2,4-dione, ammoniumthiocyanate, thiosemicarbazide and dialkylacetylene dicarboxylate using polyethylene glycol as green and recyclable solvent. The domino reaction proceeded smoothly in good-to-excellent yields.