Regioselective Synthesis of Dihydrothiophene and Thiopyran Frameworks via Catalyst-Controlled Intramolecular C_γ/C_δ–S Fusion of α‑Allyl-β′-oxodithioesters

A highly efficient and atom-economic dual reaction manifold has been developed to synthesize 4<i>H</i>-thiopyran and 4,5-dihydrothiophene frameworks via regioselective intramolecular C–S fusion of α-allyl-β′-oxodithioesters. The ring size of the sulfur-heterocycles has been efficiently tuned by the use of two different catalytic systems. Palladium activates the C_δ–H of the allyl termini and facilitates the intramolecular C_δ–S coupling to furnish six-membered thiopyran skeletons exclusively. Conversely, the allylic double bond of the same substrate has been activated by BF₃·Et₂O to promote the C_γ–S cyclization leading to the formation of a five-membered dihydrothiophene nucleus

A Strategy for the Synthesis of Anthraquinone-Based Aryl‑<i>C</i>‑glycosides

An efficient and simple strategy for the synthesis of a diverse range of anthraquinone-based aryl-<i>C</i>-glycosides has been developed. It involves the sequential Diels–Alder reaction and oxidative aromatization with the preformed glycosyl diene and dienophiles. The glycosyl dienes were obtained from simple sugars by tandem one-pot substitution and elimination reaction

Identification of 1‑[4-Benzyloxyphenyl)-but-3-enyl]‑1<i>H</i>‑azoles as New Class of Antitubercular and Antimicrobial Agents

A series of 1-[(4-benzyloxyphenyl)-but-3-enyl]-1<i>H-</i>azoles has been identified as potent antitubercular agents against <i>Mycobacterium tuberculosis</i>. Synthesis of compounds involved acid catalyzed ring-opening of cyclopropyl ring of phenyl cyclopropyl methanols followed by nucleophilic attack of the azoles on the carbocation intermediates. Several of the compounds <b>26</b>, <b>34</b>, and <b>36</b> exhibited significant antitubercular activities with MIC value as low as 1.56, 1.56, and 0.61 μg/mL, respectively, comparable to many standard drugs. These compounds were also screened against other strains of bacteria and fungi, and few of them showed good antifungal activity against <i>A. fumigatus</i>, responsible for lung infection