Syntheses of biodynamic heterocycles: baker’s yeast-assisted cyclocondensations of organic nucleophiles and phenacyl chlorides

An efficient synthesis of mono-, di-, and tri-substituted 1,3-thiazoles employing functionalized thioamides as thiocarbonyl precursors

Herein, we report an efficient strategy to synthesize functionalized 1,3-thiazoles using alkyl 2-amino-2-thioxoacetates. Thioamides, the synthetic precursors, react effortlessly with electrophilic reagents and are transformed into a series of phenyl-, methyl-, and acyl-substituted thiazoles with high functionalization at the 2nd position through sequential C-S/C-N bond formation. Rapid reaction times under metal-free mild conditions is a noteworthy feature of the reported protocol. Given the intriguing biological significance of the synthesized molecules, we further performed a comprehensive evaluation of their potency against the SARS-CoV-2 receptor (PDB ID: 7mc6) using a molecular docking approach, with binding scores ranging from -4.3 to -8.2 kcal mol-1.

Baker’s yeast (Saccharomyces cerevisiae) catalyzed synthesis of bioactive heterocycles and some stereoselective reactions

Saccharomyces cerevisiae, commonly known as baker’s yeast, has gained significant importance as a mild, low-cost, environmentally benign biocatalyst. Initially it was mostly employed as an efficient catalyst for the enantioselective reduction of carbonyl compounds. Over the last decade, baker’s yeast has found versatile catalytic applications in various organic transformations. Many multicomponent reactions were also catalyzed by baker’s yeast. Various heterocyclic scaffolds with immense biological activities were synthesized by employing baker’s yeast as catalyst at room temperature. In this communication, we have summarized baker’s yeast catalyzed various organic transformations focusing primarily on heterocyclic synthesis.

Brønsted acid-promoted thiazole synthesis under metal-free conditions using sulfur powder as the sulfur source

A Brønsted acid-promoted sulfuration/annulation reaction for the one-pot synthesis of bis-substituted thiazoles from benzylamines, acetophenones, and sulfur powder has been developed. One C–N bond and multi C–S bonds were selectively formed in one pot. The choice of the Brønsted acid was the key to the high efficiency of this transformation under metal-free conditions.

A Brønsted acid-promoted protocol for the synthesis of 2,4-disubstituted thiazoles from benzylamines, acetophenones, and sulfur powder under metal-free conditions is described.

Heterocycles 48. Synthesis, Characterization and Biological Evaluation of Imidazo[2,1-b][1,3,4]Thiadiazole Derivatives as Anti-Inflammatory Agents

Non-steroidal anti-inflammatory drugs (NSAIDs) are an important pharmacological class of drugs used for the treatment of inflammatory diseases. They are also characterized by severe side effects, such as gastrointestinal damage, increased cardiovascular risk and renal function abnormalities. In order to synthesize new anti-inflammatory and analgesic compounds with a safer profile of side effects, a series of 2,6-diaryl-imidazo[2,1-b][1,3,4]thiadiazole derivatives 5a⁻l were synthesized and evaluated in vivo for their anti-inflammatory and analgesic activities in carrageenan-induced rat paw edema. Among all compounds, 5c showed better anti-inflammatory activity compared to diclofenac, the standard drug, and compounds 5g, 5i, 5j presented a comparable antinociceptive activity to diclofenac. None of the compounds showed ulcerogenic activity. Molecular docking studies were carried out to investigate the theoretical bond interactions between the compounds and target, the cyclooxygenases (COX-1/COX-2). The compound 5c exhibited a higher inhibition of COX-2 compared to diclofenac.

Baker’s yeast catalyzed one-pot synthesis of bioactive 2-[benzylidene(or pyrazol-4-ylmethylene)hydrazono]-1,3-thiazolidin-4-one-5-yl-acetic acids

An efficient and simple one-pot protocol has been developed for synthesis of substituted derivatives of 2-hydrazono-4-thiazolidinone-5-acetic acids 4a–j and 6a–g by cyclocondensation of aryl/pyrazolyl aldehyde, thiosemicarbazide and maleic anhydride in acetonitrile in the presence of readily available whole cell biocatalyst, baker’s yeast (Saccharomyces cerevisiae). The reaction is enhanced by ultrasonication.