Antituberculosis agents x. synthesis and evaluation ofIn Vitro antituberculosis activity of 2-(5-nitro-2-furyl)- and 2-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,3,4-thiadiazole derivatives

Synthesis, crystal structure and Hirshfeld surface analysis of bromido-tetra-kis-[5-(prop-2-en-1-yl-sulf-an-yl)-1,3,4-thia-diazol-2-amine-κN3]copper(II) bromide

A novel cationic complex, bromido-tetra-kis-[5-(prop-2-en-1-ylsulfan-yl)-1,3,4-thia-diazol-2-amine-κN 3]copper(II) bromide, [CuBr](C5H7N3S2)4Br, was synthesized. The complex crystallizes with fourfold mol-ecular symmetry in the tetra-gonal space group P4/n. The CuII atom exhibits a square-pyramidal coord-ination geometry. The Cu atom is located centrally within the complex, being coordinated by four nitro-gen atoms from four AAT mol-ecules, while a bromine anion is located at the apex of the pyramid. The amino H atoms of AAT inter-act with bromine from the inner and outer spheres, forming a two-dimensional network in the [100] and [010] directions. Hirshfeld surface analysis reveals that 33.7% of the inter-mol-ecular inter-actions are from H⋯H contacts, 21.2% are from S⋯H/H⋯S contacts, 13.4% are from S⋯S contacts and 11.0% are from C⋯H/H⋯C, while other contributions are from Br⋯H/H⋯Br and N⋯H/H⋯N contacts.

Crystal structure of tetra-μ-acetato-bis-[(5-amino-2-methyl-sulfanyl-1,3,4-thia-diazole-κN 1)copper(II)]

The reaction of 2-methyl-thio-5-amino-1,3,4-thia-diazole (Me-SNTD; C₃H₅N₃S₂) with copper(II) acetate monohydrate [Cu(OAc)₂·H₂O; C₄H₈CuO₅] resulted in the formation of the title binuclear compound, [Cu₂(C₂H₃O₂)₄(C₃H₅N₃S₂)₂] or [Cu₂(OAc)₄(Me-SNTD)₂]. The structure has triclinic (P ) symmetry with a crystallographic inversion centre located at the midpoint of the line connecting the Cu atoms in the dimer. These two Cu atoms of the dimer [Cu⋯Cu = 2.6727 (6) Å] are held together by four carboxyl-ate groups. Each Cu atom is further coordinated to the N atom of an Me-SNTD mol-ecule and exhibits a Jahn-Teller-distorted octa-hedral geometry. The dimers are connected into infinite chains by hydrogen bonds between the NH (Me-SNTD) and the carboxyl-ate groups of neighbouring mol-ecules, generating an R ² ₂(12) ring motif. The mol-ecules are further linked by C-H⋯π inter-actions between the thia-diazole rings and the methyl groups of the acetate units.

Pyridine and nitro-phenyl linked 1,3,4-thiadiazoles as MDR-TB inhibitors

In the present study, a series of substituted 1,3,4-thiadiazole derivatives 4(a-o), 5(a-m) and 6(a-j) were synthesized and characterized by IR, ¹H NMR, ¹³C NMR and mass spectroscopic technique. The synthesized compounds were evaluated for their in vitro anti-mycobacterial activity against the Mycobacterium tuberculosis H37Rv and resistance MDR-TB strain. Among the compounds tested N-(5-(4-nitrophenyl)-1,3,4-thiadiazol-2-yl)furan-2-carboxamide (4h) showed significant inhibitory activity with MIC of 9.87 μM (H37Rv strain) and 9.87 μM (MDR-TB strain) compared to isoniazide [MIC of 3.64 μM (H37Rv) and >200 μM (MDR-TB strain)] and rifampin [MIC of 0.152 μM (H37Rv) and 128 μM (MDR-TB strain)]. In addition, these compounds have also been assessed for their cyto-toxicity to a mammalian Vero cell line using the MTT assay. The result shows that these compounds exhibit anti-tubercular activity at non-cytototoxic concentrations.

Synthesis of new chiral 1,3,4-thiadiazole-based di- and tri-arylsulfonamide residues and evaluation of in vitro anti-HIV activity and cytotoxicity

A series of new chiral 1,3,4-thiadiazole-based bis-sulfonamides 4a-4w and tri-sulfonamide analogue 5 was synthesized and evaluated as anti-HIV agents. The reaction of chiral amino acids 1 with sulfonyl chlorides 2, followed by subsequent reaction of resultant N-protected amino acids 2a-2f with thiosemicarbazide in the presence of excess phosphorous oxychloride afforded N-(1-(5-amino-1,3,4-thiadiazol-2-yl)alkyl)-4-arylsulfonamides 3a-3f. Treatment of 2a-2f with substituted sulfonyl chlorides in portions furnished the target bis-sulfonamide analogues 4a-4w in good yields, together with the unexpected 5. The new compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compounds 4s were the most active in inhibiting HIV-1 with IC₅₀ = 9.5 μM (SI = 6.6), suggesting to be a new lead in the development of an antiviral agent. Interestingly, compound 5 exhibited significant cytotoxicity of > 4.09 μM and could be a promising antiproliferative agent.

Recent advances of imidazole-containing derivatives as anti-tubercular agents

Tuberculosis still remains one of the most common, communicable, and leading deadliest diseases known to mankind throughout the world. Drug-resistance in Mycobacterium tuberculosis which threatens to worsen the global tuberculosis epidemic has caused great concern in recent years. To overcome the resistance, the development of new drugs with novel mechanisms of actions is of great importance. Imidazole-containing derivatives endow with various biological properties, and some of them demonstrated excellent anti-tubercular activity. As the most emblematic example, 4-nitroimidazole delamanid has already received approval for treatment of multidrug-resistant tuberculosis infected patients. Thus, imidazole-containing derivatives have caused great interests in discovery of new anti-tubercular agents. Numerous of imidazole-containing derivatives were synthesized and screened for their in vitro and in vivo anti-mycobacterial activities against both drug-sensitive and drug-resistant Mycobacterium tuberculosis pathogens. This review aims to outline the recent advances of imidazole-containing derivatives as anti-tubercular agents, and summarize the structure-activity relationship of these derivatives. The enriched structure-activity relationship may pave the way for the further rational development of imidazole-containing derivatives as anti-tubercular agents.

1,3,4-thiadiazole and its derivatives: a review on recent progress in biological activities

The 1,3,4-thiadiazole nucleus is one of the most important and well-known heterocyclic nuclei, which is a common and integral feature of a variety of natural products and medicinal agents. Thiadiazole nucleus is present as a core structural component in an array of drug categories such as antimicrobial, anti-inflammatory, analgesic, antiepileptic, antiviral, antineoplastic, and antitubercular agents. The broad and potent activity of thiadiazole and their derivatives has established them as pharmacologically significant scaffolds. In this study, an attempt has been made with recent research findings on this nucleus, to review the structural modifications on different thiadiazole derivatives for various pharmacological activities.

Synthesis and antimycobacterial activity of some alkyl [5-(nitroaryl)-1,3,4-thiadiazol-2-ylthio]propionates

Two series of 2- and 3-[5-(nitroaryl)-1,3,4-thiadiazol-2-ylthio, sulfinyl and sulfonyl] propionic acid alkyl esters were synthesized and screened for antituberculosis activity against Mycobacterium tuberculosis H37Rv using the BACTEC 460 radiometric system. The MIC values for the compounds showing more than 90% inhibition were determined. The result of comparison between two groups of data exhibited that among the synthesized derivatives, the compound propyl 3-[5-(5-nitrothiophen-2-yl)-1,3,4-thiadiazol-2-ylthio]propionate was the most active one (MIC=1.56 microgml(-1)).