Synthesis and Antimicrobial activity of Piperazine analogues containing [1, 3, 4] Thiadiazole ring

A new series of piperazine-1, 3, 4-thiadiazole has been synthesized, purified and characterized with the help of their analytical and spectral data. Structures of the synthesized compounds were confirmed by IR, 1H NMR and mass spectroscopy. The potential antimicrobial effects of the synthesized compounds were investigated using Vibrio cholera and Bacillus subtilis. The newly synthesized compounds exhibited capable activities against Vibrio cholera and Bacillus subtilis and it showed minimum inhibitory concentration. In this study, few compounds showed appreciable antibacterial activity. The compound PT6 shows highly significant antibacterial and good inhibition as compared to the standard drug.

Heterocyclic Bridgehead Nitrogen Atom System: Review on [1,2,4] Triazolo[3,4-b] [1,3,4] thiadiazole and Its Pharmacological Screening.

There has been considerable interest in the development of novel anticonvulsant compounds, , analgesic, anti-inflammatory, antimicrobial, antimycobacterial, antitumour, and antitubercular activities. 1,3,4-thiadiazole constitute Significant class of compounds for new drugs development. They Have an interesting pharmacophore displaying a wide range of pharmacological activity. The 1,3,4-thiadiazole compound is an interesting heterocycle. A group that was used to synthesise a variety of useful bioactive compounds. The stability of the thiadiazole nucleus has inspired the medicinal chemist to perform various structural variations in the ring. Marketed drugs such as acetazolamide and methazolamide have shown their therapeutic potential Therefore, many researchers have identified these compounds as target structures and evaluated their biological activities. This review highlights the different pharmacological activities associated with the 1,3,4-thiadiazole ring system.

Chalcogen Bond versus Weak Hydrogen Bond: Changing Contributions in Determining the Crystal Packing of [1,2,5]-Chalcogenadiazole-Fused Tetracyanonaphthoquinodimethanes

The crystal structures of a series of tetracyanonaphthoquinodimethanes fused with a selenadiazole or thiadiazole ring revealed that their molecular packing is determined mainly by two intermolecular interactions: chalcogen bond (ChB) and weak hydrogen bond (WHB). ChB between Se and a cyano group dictates the packing of selenadiazole derivatives, whereas the S-based ChB is much weaker and competes with WHB in thiadiazole analogues. This difference can be explained by different electrostatic potentials as revealed by density functional theory calculations. A proper molecular design that weakens WHB can change the contribution of ChB in determining the crystal packing of thiadiazole derivatives.

Macrocycliczinc(II) Complexes with Tetradentate N2O2 Donor Schiff Base Ligands Incorporating 1,3,4-Thiadiazole Ring

A new series ofdiazadioxamacrocycliczinc(II) derivatives [{Zn(M)(H2O)2}(OAc)2] (M= macrocyclic ligands) prepared via template synthesis method, by the reaction of Schiff bases derived from bis-(2-hydrazino-1,3,4-thiadiazole-5-yl)arene/alkanes and 3,5-dichlorosalicyldehyde/2-hydroxy-1-naphthaldehyde with 1,4-dibromobutane in the presence of Zn(II) ion. The structures of all these complexes were established on the basis of elemental analyses, spectral data (IR and 1H-NMR), PXRD, SEM techniques. Presence of coordinated water molecules in the Zn(II) complexes were confirmed by TGA analyses. The antimicrobial effects of all the synthesized complexes were evaluated against different species of pathogenic fungi (A. niger, A. alternata ) and bacteria (E. coli, B. subtilis).

Thiadiazole derivatives as anticancer agents

In spite of substantial progress made toward understanding cancer pathogenesis, this disease remains one of the leading causes of mortality. Thus, there is an urgent need to develop novel, more effective anticancer therapeutics. Thiadiazole ring is a versatile scaffold widely studied in medicinal chemistry. Mesoionic character of this ring allows thiadiazole-containing compounds to cross cellular membrane and interact strongly with biological targets. Consequently, these compounds exert a broad spectrum of biological activities. This review presents the current state of knowledge on thiadiazole derivatives that demonstrate in vitro and/or in vivo efficacy across the cancer models with an emphasis on targets of action. The influence of the substituent on the compounds’ activity is depicted. Furthermore, the results from clinical trials assessing thiadiazole-containing drugs in cancer patients are summarized.

2-Amino-1,3,4-thiadiazoles as prospective agents in trypanosomiasis and other parasitoses

Parasitic diseases are a serious public health problem affecting hundreds of millions of people worldwide. African trypanosomiasis, American trypanosomiasis, leishmaniasis, malaria and toxoplasmosis are the main parasitic infections caused by protozoan parasites with over one million deaths each year. Due to old medications and drug resistance worldwide, there is an urgent need for new antiparasitic drugs. 1,3,4-Thiadiazoles have been widely studied for medical applications. The chemical, physical and pharmacokinetic properties recommend 1,3,4-thiadiazole ring as a target in drug development. Many scientific papers report the antiparasitic potential of 2-amino-1,3,4-thiadiazoles. This review presents synthetic 2-amino-1,3,4-thiadiazoles exhibiting antitrypanosomal, antimalarial and antitoxoplasmal activities. Although there are insufficient results to state the quality of 2-amino-1,3,4-thiadiazoles as a new class of antiparasitic agents, many reported derivatives can be considered as lead compounds for drug synthesis and a promise for the future treatment of parasitosis and provide a valid strategy for the development of potent antiparasitic drugs.

Synthesis and antimicrobial evaluation of Histidine Cinnamaldehyde Schiff base containing structural feature of 1, 3, 4-thiadiazole heterocyclic moiety

Reaction of aqueous solution of amino acid Histidine with ethanolic solution Cinnamaldehyde to synthesize the desired Schiff base. Then, the derivative of 1, 3, 4-thiadiazole ring have been synthesized by reaction of the imine derivative with Thiosemicarbazide in presence of POCL3. The entire intermediate and final compound characterized and identified by elemental microanalysis as melting point, FT-IR spectra, 1H-NMR spectroscopy. Agar Well Diffusion method evaluated the antimicrobial activity on gram positive bacteria such as Staphylococcus aureus and Streptococcus pneumonia and gram-negative bacteria such as E coli & Acinetobacter species and also antifungal activity had been studied on one type of fungi (candida albicans).

Recent Developments in the Synthesis of 1,2,5-Thiadiazoles and 2,1,3-Benzothiadiazoles

The fast-growing interest in 1,2,5-thiadiazoles and their fused analogues including 2,1,3-benzothiadiazoles in recent years as important compounds in materials science and biomedicine has led to great progress in the synthesis of these heterocyclic systems. In this short review, the development of known procedures together with novel reactions is covered. New starting materials, unknown and unexpected transformations for the construction of the thiadiazole ring are emphasized.1 Introduction2 Synthesis of Monocyclic 1,2,5-Thiadiazoles2.1 From 1,2-Diamines, vic-Dioximes and Related Compounds2.2 From Alkyl Aryl (Hetaryl) Ketoximes and Tetrasulfur Tetranitride2.3 By Condensation Reactions2.4 From Other Heterocycles3 Synthesis of Fused 1,2,5-Thiadiazoles3.1 From ortho-Phenylenediamines and Related Compounds3.2 From ortho-Aminonitroso and ortho-Aminonitro Derivatives3.3 By Condensation Reactions3.4 By Chalcogen Exchange in 1,2,5-Oxa- and 1,2,5-Selenadiazoles3.5 Miscellaneous Methods4 Conclusions

The crystal structures and Hirshfeld surface analyses of four 3,5-diacetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl derivatives

The title compounds, 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl benzoate, C20H19N3O4S (I), 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl isobutyrate 0.25-hydrate, C17H21N3O4S·0.25H2O (II), 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl propionate, C16H19N3O4S (III) and 4-(5-acetamido-3-acetyl-2-methyl-2,3-dihydro-1,3,4-thiadiazol-2-yl)phenyl cinnamate chloroform hemisolvate, C22H21N3O4S·0.5CHCl3 (IV), all crystallize with two independent molecules (A and B) in the asymmetric unit in the triclinic P\overline{1} space group. Compound II crystallizes as a quaterhydrate, while compound IV crystallizes as a chloroform hemisolvate. In compounds I, II, III (molecules A and B) and IV (molecule A) the five-membered thiadiazole ring adopts an envelope conformation, with the tetrasubstituted C atom as the flap. In molecule B of IV this ring is flat (r.m.s. deviation 0.044 Å). The central benzene ring is in general almost normal to the mean plane of the thiadiazole ring in each molecule, with dihedral angles ranging from 75.8 (1) to 85.5 (2)°. In the crystals of all four compounds, the A and B molecules are linked via strong N—H...O hydrogen bonds and generate centrosymmetric four-membered R 4 4(28) ring motifs. There are C—H...O hydrogen bonds present in the crystals of all four compounds, and in I and II there are also C—H...π interactions present. The intermolecular contacts in the crystals of all four compounds were analysed using Hirshfeld surface analysis and two-dimensional fingerprint plots.

Heterocycle Effects on the Liquid Crystallinity of Terthiophene Analogues

Liquid crystalline self-assembly offers the potential to create highly ordered, uniformly aligned, and defect-free thin-film organic semiconductors. Analogues of one of the more promising classes of liquid crystal semiconductors, 5,5”-dialkyl-α-terthiophenes, were prepared in order to investigate the effects of replacing the central thiophene with either an oxadiazole or a thiadiazole ring. The phase behaviour was examined by differential scanning calorimetry, polarized optical microscopy, and variable temperature x-ray diffraction. While the oxadiazole derivative was not liquid crystalline, thiadiazole derivatives formed smectic C and soft crystal lamellar phases, and maintained lamellar order down to room temperature. Variation of the terminal alkyl chains also influenced the observed phase sequence. Single crystal structures revealed the face-to-face orientation of molecules within the layers in the solid-state, a packing motif that is rationalized based on the shape and dipole of the thiadiazole ring, as corroborated by density functional theory (DFT) calculations. The solution opto-electronic properties of the systems were characterized by absorption and emission spectroscopy, cyclic voltammetry, and time-dependent density functional theory (TD-DFT).