Many compounds containing a five-membered heterocyclic ring display exceptional chemical properties and versatile biological activities. In this Minireview, thiadiazoles are summarized according to their therapeutic potential, highlighting the versatility of this scaffold in medicinal chemistry. The unique properties of thiadiazoles are also discussed in relation to their potential effect on activity. Thiadiazole is a bioisostere of pyrimidine and oxadiazole, and given the prevalence of pyrimidine in nature it is unsurprising that thiadiazoles exhibit significant therapeutic potential. The sulfur atom of the thiadiazole imparts improved liposolubility, and the mesoionic nature of thiadiazoles makes these compounds better able to cross cellular membranes. By summarizing the thiadiazole-containing compounds reported in recent decades, we aim to give a brief introduction to their synthesis and diverse biological activities, such as anti-inflammatory, anticancer, antibacterial, antifungal, antiviral, antiparasitic, anticonvulsant, anticoagulant, antidiabetic, and to show the significant utility of the thiadiazole scaffolds in medicinal chemistry.

Addition of catalytic amounts of a phosphite‐based gold(I) catalyst efficiently triggers the intermolecular [2+2] cycloaddition of allenes and alkenes substituted by electron‐donor groups. The reaction is fast and furnishes cyclobutane derivatives in a stereoselective manner using low catalyst loadings. Besides, the same catalyst selectively affords homodimerization products from the starting allene, a process that may be conveniently fine tuned by addition of norbornene.

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