Non-catalytic approach to the synthesis of partially reduced ‘S’ shaped dioxathia-, and oxadithiahelicenes through base induced inter-, and intramolecular C–C bond formation

Hardesh K. Maurya, Vishnu K. Tandon, Brijesh Kumar, Abhinav Kumar, Volker Hüch and Vishnu Ji Ram

Org. Biomol. Chem., 2012, 10, 605-613                                                               DOI: 10.1039/C1OB06091K

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An efficient and convenient route for the construction of helical ‘S’ shaped dioxathia- and oxadithiahelicenes with oxygen and sulfur atoms located in the middle of the outer helix has been developed through base induced inter-, and intramolecular C-C bond formation from the reaction of 4-sec.amino-2-oxo-2,5-dihydrothiochromeno[4,3-b]pyran-3-carbonitriles with 3,4-dihydro-2H-benzo[b]oxepin-5(2H)-ones, 3,4-dihydrobenzo[b]thiepin-5(2H)-one and thiochroman-4-ones separately. Quantum chemical calculations have also been carried out to explore the geometries and electronic structures of newly synthesized compounds to envisage the pathway for interconversion of both atropisomers. The determination of helicity parameters and configurational stability demonstrate that the energy barrier is strongly dependent on the nature of hetero atoms present.

Micelles catalyzed chemoselective synthesis ‘in water’ and biological evaluation of oxygen containing hetero-1,4-naphthoquinones as potential antifungal agents

Bioorganic & Medicinal Chemistry Letters  Volume 21, Issue 21, 1 November 2011, Pages 6398-6403                                                           doi:10.1016/j.bmcl.2011.08.095

Vishnu K.Tandon, Hardesh K. Maurya, Nripendra N. Mishra and Praveen K. Shukla

Various oxygen containing 1,4-naphthoquinone derivatives have been synthesized chemoselectively by an economical, viable green methodology approach using water as solvent with or without surfactants such as Triton X-100, SDS, LD (laundry detergent) and TBAB, a phase transfer catalyst and evaluated for their in vitro antifungal and antibacterial activity. The antifungal profile of 3, 4a, 4b and 6 indicated that compounds 3a, 3b, 4b, 6a and 6c have potent antifungal activity compared to clinically prevalent antifungal drugs Fluconazole and Amphotericin-B against Sporothrix schenckii, Trichophyton mentagraphytes and Candida parapsilosis and compound 3b has been found to be a lead antifungal agent for further study.