To develop the newer pharmaceuticals and to spur the strong growth, being a general property of 'handedness', chirality plays a major role. The Easson-Stedman principle shows the differences in the biological activity between enantiomers resulted from selective reactivity of one enantiomer with its receptor. It helps to improve the pharmacokinetic properties and to remove undesirable side effects by virtue of the unique activity of enantiomers. Racemic switching and marketing drug combinations are used as tools for drug life-cycle management and to redevelop racemic mixtures as single enantiomers.

Tetrahydrothiopyrans have been efficiently synthesized in good yields with excellent diastereoselectivity from aldehydes and substituted 5-methylhex-4-ene-1-thiol via (3,5)-thionium-ene cyclization reaction mediated by boron trifluoride etherate.

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The interaction of naproxen with b-cyclodextrin and its derivatives (hosts) as well as polymer has been studied using UV Visible (UV-Vis), Fourier Transform Infrared (FTIR), Nuclear Magnetic Resonance (NMR) spectroscopy and Scanning electron microscopy (SEM). In this paper, the solid inclusion complexes were prepared by freeze drying method. The formation constants of the complexes were determined by UV-Vis method. The adsorption properties of naproxen with b-Cyclodextrin bonded silica stationary phase (CDS) were studied for an in-depth understanding of the host-guest interaction. The inclusion process involving naproxen and hosts was investigated by using the PM3 quantum-mechanical semiempirical method. The stabilization energy values obtained from the semiempirical calculation showed the same relation with the formation constant values determined by UV-Vis spectroscopy.

Indium triflate can be efficiently used for Prins cyclization of acrylyl enol ethers to give tetrahydrofuran ring stereo- and regioselectively in good yields. The formation of five-membered rings is against the Baldwin's rule.

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An efficient methodology for the synthesis of oxabicyclo[3.3.1]nonenes and substituted tetrahydropyrans has been developed in moderate yields from the reaction of geraniol with aldehydes and epoxides promoted by boron trifluoride etherate.

Tetrahydrothiophenes and -thiopyrans have been efficiently synthesized from thioacrylates via thia-Prins cyclization reaction mediated by trimethylsilyltrifluoromethanesulfonate with good diastereoselectivity and in good to high yields.