Synthesis and antileishmanial activity of 5-(5-nitroaryl)-2-substituted-thio-1,3,4-thiadiazoles

Novel 5-(nitrothiophene-2-yl)-1,3,4-Thiadiazole Derivatives: Synthesis and Antileishmanial Activity against promastigote stage of Leishmania major

In this study, a series of novel compounds based on 5-(5-nitrothiophene-2-yl)-1,3,4-thiadiazole possessing (het) aryl thio pendant at C-2 position of thiadiazole ring is developed and evaluated as antileishmanial agents using MTT colorimetric assay. 10 New compounds containing aryl and heteroaryl derivatives, started from thiophene-2-carbaldehyde in five steps, were synthesized in good to excellent yields and characterized by ¹H-NMR, ¹³C-NMR, and IR spectroscopy. Through the compounds 6a-j, methylimidazole containing derivative 6e was recognized as the most active compound against L. major promastigotes exhibiting IC₅₀ values of 11.2µg/mL and 7.1µg/mL after 24 and 48 h, respectively. This compound is > 4 fold more effective than Glucantime as a standard drug (IC₅₀ = 50 µg/mL after 24 h and 25 µg/mL after 48 h).

An overview of azoles targeting sterol 14α-demethylase for antileishmanial therapy

The azole antifungal drugs are an important class of chemotherapeutic agents with broad-spectrum of activity against yeasts and filamentous fungi, act in the ergosterol biosynthetic pathway through inhibition of the cytochrome P450-dependent enzyme sterol 14α-demethylase. Azole antifungals have also been repurposed for treatment of tropical protozoan infections including human leishmaniasis. Recent advances in molecular biology and computational chemistry areas have increased our knowledge about sterol biochemical pathway in Leishmania parasites. Based on the importance of sterol biosynthetic pathway in Leishmania parasites, we reviewed all studies reported on azoles for potential antileishmanial therapy along their structural and biological aspects. This review may help medicinal chemists for design of new azole-derived antileishmanial drugs.

Thiadiazole inhibitors: a patent review

INTRODUCTION

Four isomeric structures of thiadiazole motifs have outstanding pharmacological inhibitory applications are reported in this review. Thiadiazole nucleus is present in several biologically active natural products and commercial drugs. Most of thiadiazoles reported herein are emphasized to have broad spectrum of medicinal activities. Areas covered: This review represents the recent inhibitory activities of thiadiazole isomeric scaffolds and their broad-spectrum biological applications published as full texts during 2010-2016 as well as the patents published during 2005-2016. The inhibition areas covered included anti-inflammatory, antimicrobial, antitumor, antioxidant, antitubercular, antiviral, antileishmanial, anticonvulsant, herbicidal and algicidal activities in addition to enzymes, human platelet aggregation and neuroprotective inhibitors. Expert opinion: This survey revealed very interesting data about the applications of thiadiazoles, where some synthetic or natural thiadiazole derivatives were components of drugs available in the market. Many thiadiazole derivatives can be considered as lead compounds for drug synthesis. The most inhibitory active 1,3,4-thiadiazole compounds are those incorporating secondary alkyl(aryl)amido- and/or benzylthio(mercapto) groups at positions 2 and 5. Several thiadiazole derivatives demonstrated higher antibacterial, antitumor and antiviral activities than the standard drugs. Some thiadiazole derivatives exhibited high selective enzymes inhibitory activities based on the electronic properties of the substituents at positions 2 or 5.

Antileishmanial drug discovery: comprehensive review of the last 10 years

This review covers the current aspects of leishmaniasis including marketed drugs, new antileishmanial agents, and possible drug targets of antileishmanial agents.

A convenient four-component one-pot synthesis of 2-amino-1,3,4-thiadiazoles in water

A novel four-component one-pot approach for the synthesis of 2-amino-1,3,4-thiadiazoles from primary amines, carbon disulfide, hydrazine, and acyl chlorides has been developed. A series of 5-substituted-2-amino-1,3,4-thiadiazoles were synthesized in medium-to-good yields utilizing this newly developed method.

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 biological activity of 5-nitrofuran-containing (1,3,4-thiadiazol-2-yl)piperazine moieties as a new type of anti-Helicobacter pylori heterocycles

In order to find new and potent drug candidates for the treatment of Helicobacter pylori infections? in this study attention was focused on the synthesis and anti-H. pylori activity of a series of 5-(5-nitrofuran-2- yl)-1,3,4-thiadiazoles containing piperazinyl functionality at the C-2 position of the 1,3,4-thiadiazole ring. The synthesis of 1-[5-(5-nitrofuran- 2-yl)-1,3,4-thiadiazol-2-yl]piperazine derivatives (3a-h) and pyrrolidine derivative 3i was achieved with a versatile and efficient synthetic route via 2-chloro-5-(5-nitrofuran-2-yl)-1,3,4-thiadiazole. The inhibitory activity of the new derivatives 3a-i against twenty clinical H. pylori strains was evaluated by the disc diffusion method and compared with the commercially available standard drug metronidazole Resulting biological data indicated that most compounds exhibited strong inhibitory activity even at doses lower than 2 ?g disc-1 (average of inhibition zone >20 mm) while metronidazole had little or no growth inhibition at this dose. Compound 3c containing the N-benzoylpiperazin-1-yl moiety showed the most potent inhibitory activity.