The ever-increasing spread of bacterial infection with rising antibacterial drug resistance has become a matter of global concern in the modern times. Therefore, such serious infections leading to high mortality rate has necessitated the search for new classes of effective antibacterial agents with minimum toxicity. Herein, we report the synthesis and identification of a new class of benzofuran based Schiff ligands (6a-6e) and their Cu/Zn complexes (7a-7j) via sequential reactions starting with Salicylaldehyde. Compounds 6a, 7c and 7e exhibit activity in the low microgram range against M. tuberculosis, showing the minimum inhibitory concentrations (MICs) of 1.6 μg/mL. The compounds 6e and 7b also show interesting antibacterial activity against S. Aureus, E. coli and B. Subtilis with comparable area of inhibition of standard drugs under study. This research suggests that benzofuran based compounds can serve as a promising lead scaffold in developing new drugs to combat microbial infections. GRAPHICAL ABSTRACT

: Tuberculosis (TB) is a major cause of mortality and illness as reported by the W.H.O in 2019. The WHO report also mentioned the fact that about 10.0 million people fell ill with tuberculosis in the year 2018. Hydrazide–hydrazones having azomethine group (–NH–N=CH–) connected with carbonyl group is reported for the number of bioactivities like anti-inflammatory, anticonvulsant, anticancer, antiviral and antiprotozoal. Objective: The objective of our current study is to design and synthesis of more potent Hydrazide–hydrazones containing anti-Tubercular agents. Methods: In the current study, we synthesized 10 hydrazones (3a-3j) by stirring corresponding benzohydrazides (2) with substituted aldehydes (1a-j) in ethanol as a solvent and acetic acid as a catalyst at room temperature. All synthesized compounds were characterized by various spectroscopic techniques including elemental analysis, ultraviolet–visible spectroscopy, fluorescence, fourier- transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Compounds (3a-3j) were tested for in vitro anti-TB activity using Microplate Alamar Blue Assay (MABA). Results: All our synthesized compounds (3a-3j) were found to be potent against Mycobacteria tuberculosis (H37RV strain) with MIC (minimum inhibitory concentrations) values of 3.125-50 μg/mL. The hydrazide CO-NH protons in (3a-j) compounds are highly deshielded and showed broad singlet at 9.520-9.168 ppm. All the compounds were found to have more intense emission in the 416 – 429 nm regions and strong absorption in the regions of 316 – 327 nm. Synthesized compounds were also tested for in silico analysis using different software for their Absorption, Distribution, Metabolism, Excretion and Toxicity (ADMET) analysis. All the compounds were found to be in silico non-carcinogenic. Conclusion: Our current study will definitely help the medicinal chemists for better designing of newer potent anti-Tubercular agents.

Background: For the past several decades, the presence of tuberculosis (TB) is being remarked as the most common infectious disease leading to mortality. Objective: Hydrazone containing azometine group (-NHN=CH-) compounds have been reported for a broad range of bioactivities such as antiplatelet, analgesic, anti-inflammatory, anticonvulsant, antidepressant, antimalarial, vasodilator, antiviral, and antimicrobial, etc. Methods: For the synthesis of compounds (4a-4d) and (6a-6e), aromatic amines were treated with methyl terephthalaldehydate in methanol, giving Schiff’s bases, followed by reductive amination and further treatment with hydrazine hydrate gave acid hydrazides (4a-4d). These acid hydrazides were then treated with different aromatic aldehydes to yield hydrazones (6a-6d). All the synthesized compounds were subjected to FT-IR, NMR, and UV spectroscopic characterization. Results: Compounds (4a-4d) and (6a-6e) were found to have highly potent activity against Mycobacteria tuberculosis (Vaccine strain, H37 RV strains): ATCC No- 27294 (MIC:1.6-6.25 μg/mL) than standard anti-TB drugs. The compounds exhibited good radical scavenging potentials(0- 69.2%), as checked from DPPH protocol. All compounds also demonstrated good in-silico ADMET results. Conclusion: The current study revealed promising in vitro anti-tuberculosis and anti-oxidant profiles of hydrazide-hydrazone analogues.

Background: A series of new six thiazolyl-2-amine-based Schiff base derivatives (4a-4f) were synthesized by a sequential multistep reaction starting with Salicylaldehyde. Methods: All the Schiff base derivatives were screened in-vitro for their antibacterial activity against Mycobacterium tuberculosis (H37RV strain) ATCC No-27294. The synthesized compounds were characterized by FTIR, 1H-NMR, 13C-NMR and Mass spectrometry. Results: Among the compounds tested, 4c and 4f derivatives exhibited potent antitubercular activity against M. tuberculosis at MIC 6.25 μg/mL. Conclusion: We extended our study to explore the inhibition mechanism by conducting molecular docking analysis by using Schrodinger’s molecular modeling software. All the newly synthesized compounds were found to be in-silico AMES test non-toxic and non-carcinogens. The good Qikprop’s Absorption, Distribution, Metabolism and Excretion (ADMET) would definitely help the researchers in order to make more potent Anti-TB agents.

Background: Antimicrobial resistance is a major global health problem, which is being rapidly deteriorating the quality of human health. Series of substituted N-(benzo[d]thiazol-2-yl)-2- (4-(6-fluorobenzo[d]isoxazol-3-yl) piperidin-1-yl)acetamide (3a-j) were synthesized from substituted N-(benzo[d]thiazol-2-yl)-2-chloroacetamide/bromopropanamide (2a-j) and 6-fluoro-3- (piperidin-4-yl)benzo[d]isoxazole (2) and further evaluated for their docking properties and antimicrobial activity. Methods: All the synthesized compounds were characterized by FT-IR, NMR and Mass spectral analysis. All compounds were allowed to dock against different antimicrobial targets having PDB ID: 1D7U and against common antifungal target having PDB ID: 1EA1. Results: The compounds 3d and 3h showed good activity against Methicillin-resistant Staphylococcus aureus (MRSA, resistance Gram-positive bacteria). All synthesized compounds showed good to moderate activity against selected bacterial and fungal microbial strains. If we compared the actual in-vitro antimicrobial activity and in silico molecular docking study, we found that molecules 3i and 3h were more potent than the others. Conclusion: Our current study would definitely pave the new way of designing and synthesis of more potent 2-aminobenzothiazoles derivatives.

Background: Since the last few decades, the healthcare sector is facing the problem of the development of multidrug-resistant (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) infections all over the world. Regardless of the current healthcare progress for the treatment of mycobacterial infections, we are still unable to control addition of every year 9 million new cases of tuberculosis (TB). Objective: We had an objective to synthesize some novel hydrazones, which were further subjected to characterization, Photoluminescence study, in vitro anti-mycobacterium testing and in silico ADMET predictions. Methods: Some new hydrazone derivatives have been successfully prepared by the condensation reaction in the present study. All the compounds were characterized by using FTIR, NMR, UV, Fluorescence spectroscopic techniques. Results: All our newly synthesized compounds showed strong electronic excitation at 292.6 – 319.0 nm and displayed more intense emissions in the 348 – 365 nm regions except compound 3i. The newly synthesized hydrazones 3a, 3b, 3f and 3g were found to be the most active compounds and showed MIC (Minimum inhibitory concentrations) values of 12.5 μg/mL. Conclusion: In the realm of development of more potent, effective, safer and less toxic antituberculosis agents; our current study would definitely help the medicinal chemists to develop potent analogues containing hydrazine motifs in them.