Synthesis, potent anti-TB activity against M. tuberculosis ATTC 27294, crystal structures and complex formation of selected 2-arylidenehydrazinylbenzothiazole derivatives

Synthesis and Characterization of Novel Hydrazone Complexes: Exploring DNA/BSA Binding and Antimicrobial Potential

Research involving coordination chemistry with Schiff base hydrazones finds applications in various areas, particularly in bioinorganic chemistry and biomedicine. This work aims to contribute to this field by employing the ligand (E)-2-((2-(benzothiazol-2-yl)hydrazone)methyl)phenol (H2L), synthesized via a condensation reaction with salicylic aldehyde. The ligand was isolated, characterized, and subsequently complexed with nickel(II) chloride and copper(II) nitrate, yielding three new crystalline complexes: [Ni(HL)2] (1), [Ni2(L)2(Py)2(EtOH)]·DMF·0.5H2O (2), and [Cu3(L#)2(DMF)2] (3) (where Py = pyridine). The metal complexes were structurally characterized using IR, UV-vis, TGA-DSC, and SCXRD techniques. These analyses confirmed the coordination of the ligand to the metal center via nitrogen and oxygen donor atoms, establishing the formation of mono-, bi-, and trinuclear complexes, respectively. DNA interaction studies were performed through spectroscopic titration and viscosity measurements, indicating that the complexes interact via an intercalative mode, with the interaction order being 3 > 2> 1. Partition coefficient analysis revealed that complexes 1 and 3 have a greater tendency to partition into the organic phase, suggesting their potential to cross lipid membranes, while complex 2 and the ligand are more hydrophilic. Fluorescence-based BSA binding studies demonstrated interactions between the complexes and the biomolecule, following the same order as observed in the DNA interaction. Biological tests showed that the ligand lacked antimicrobial and antiyeast activity, while the metal complexes are biologically active. Notably, the copper complex displayed the strongest antibacterial effect, likely due to copper's essential biological role.

Synthesis, biological evaluation and mechanism of action of benzothiazole derivatives with aromatic hydrazone moiety, a new class of antileishmanial compounds

Leishmaniasis is a disease caused by protozoa Leishmania spp., considered as a significant and urgent public health problem mainly in developing countries. In the absence of an effective vaccine, the treatment of infected people is one of the most commonly prophylactic measures used to control this disease. However, the therapeutic arsenal is reduced to a few drugs, with serious side effects and variability in efficacy. Attempting to this problem, in this work, a series of benzothiazole derivatives was synthetized and assayed against promastigotes and intracellular amastigotes of L. amazonensis, as well as the toxicity on macrophages. In addition, studies about the mechanism of action were also performed. Among the synthesized molecules, the substitution at position 4 of the aromatic ring appears to be critical for activity. The best compound exhibited IC50 values of 28.86 and 7.70 μM, against promastigotes and amastigotes of L. amazonensis, respectively, being more active than miltefosine, used as reference drug. The in silico analysis of physicochemical and pharmacokinetic (ADMET) properties of this compound suggested a good profile of oral bioavailability and safety. In conclusion, the strategy of using benzothiazole nucleous in the search for new antileishmanial agents was advantageous and preliminar data provide information about the mechanism of action as well as in silico parameters suggest a good profile for preclinical studies.

Recent advances in the synthesis of new benzothiazole based anti-tubercular compounds

This review highlights the recent synthetic developments of benzothiazole based anti-tubercular compounds and their in vitro and in vivo activity. The inhibitory concentrations of the newly synthesized molecules were compared with the standard reference drugs. The better inhibition potency was found in new benzothiazole derivatives against M. tuberculosis. Synthesis of benzothiazole derivatives was achieved through various synthetic pathways including diazo-coupling, Knoevenagel condensation, Biginelli reaction, molecular hybridization techniques, microwave irradiation, one-pot multicomponent reactions etc. Other than recent synthetic developments, mechanism of resistance of anti-TB drugs is also incorporated in this review. Structure activity relationships of the new benzothiazole derivatives along with the molecular docking studies of selected compounds have been discussed against the target DprE1 in search of a potent inhibitor with enhanced anti-tubercular activity.

A study of antituberculosis activities and crystal structures of (E)-2-[2-(arylidene)hydrazinyl]pyrimidine and (E)-N 1-(arylidene)pyrimidine-2-carbohydrazide derivatives

A study of the anti-tuberculosis activity against Mycobacterium tuberculosis ATTC 27294 and an X-ray structural determination of (E)-2-[2-(arylidene)hydrazinyl]pyrimidine, 1, and (E)-N 1-(arylidene)pyrimidine-2-carbohydazide, 2, derivatives are presented. The effect of the substituents in the aryl moiety on the antituberculosis (anti-TB) activities of 1 and 2 is compared with that of other heteroaryl hydrazonyl and acylhydrazonyl derivatives. The biological activities of 1 do not depend on the coordinating ability of the substituted aryl group: in 2, the most effective aryl group is 5-nitrofuranyl. The structure determinations of (E)-2-((2-(pyrimidin-2-yl)hydrazono)methyl)-phenol, (E)-N′-(2,5-dihydroxybenzylidene)pyrimidine-2-carbohydrazide and of the hydrate of (E)-N′-(2-hydroxy-4-methylbenzylidene)pyrimidine-2-carbohydrazide, and a literature search of related structures in the CCDC data base, allowed an examination of the more important interactions, including the occurrence of X–Y⋯π interactions.

N'-(1,3-Benzo-thia-zol-2-yl)benzene-sulfono-hydrazide: crystal structure, Hirshfeld surface analysis and computational chemistry

The asymmetric unit of the title compound, C13H11N3O2S2, comprises two independent mol-ecules (A and B); the crystal structure was determined by employing synchrotron radiation. The mol-ecules exhibit essentially the same features with an almost planar benzo-thia-zole ring (r.m.s. deviation = 0.026 and 0.009 Å for A and B, respectively), which forms an inclined dihedral angle with the phenyl ring [28.3 (3) and 29.1 (3)°, respectively]. A difference between the mol-ecules is noted in a twist about the N-S bonds [the C-S-N-N torsion angles = -56.2 (5) and -68.8 (5)°, respectively], which leads to a minor difference in orientation of the phenyl rings. In the mol-ecular packing, A and B are linked into a supra-molecular dimer via pairwise hydrazinyl-N-H⋯N(thiazol-yl) hydrogen bonds. Hydrazinyl-N-H⋯O(sulfon-yl) hydrogen bonds between A mol-ecules assemble the dimers into chains along the a-axis direction, while links between centrosymmetrically related B mol-ecules, leading to eight-membered {⋯HNSO}2 synthons, link the mol-ecules along [001]. The result is an undulating supra-molecular layer. Layers stack along the b-axis direction with benzo-thia-zole-C-H⋯O(sulfon-yl) points of contact being evident. The analyses of the calculated Hirshfeld surfaces confirm the relevance of the above inter-molecular inter-actions, but also serve to further differentiate the weaker inter-molecular inter-actions formed by the independent mol-ecules, such as π-π inter-actions. This is also highlighted in distinctive energy frameworks calculated for the individual mol-ecules.