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Differentially substituted 1,3-diaryl-substituted allylic cations generated by ionization of the corresponding allylic alcohols in the presence of a Lewis acid has undergone chemoselective and regioselective electrocyclization reactions in order to produce 1-aryl-1H-indenes. An unusual dimerization reaction has occurred to produce a cyclopenta[a]indene by a formal cationic 2[pi]+2[pi] cycloaddition of the allylic cation with the intermediate indene.

The introduction of ring strain in the dienophile, as with moderately strained bicycle[2.2.1]heptenes (norbornene), has enabled three-component Povarov reaction with in situ formed N-arylimines under Lewis acid catalyzed conditions (B[F.sub.3].O[Et.sub.2]). The preference for the formation of exo-exo diastereomic adducts is seen in most cases, but the formation of exo-endo adducts is observed for reactions of ortho- or meta-substituted anilines.

Carvedilolis a uniquely effective drug for the treatment of cardiacarrhythmias in patients with heart failure. This activity is in partbecause of its ability to inhibit store-overload-induced calcium release(SOICR) through the RyR2 channel. We describe the synthesis, characterization,and bioassay of ca. 100 compounds based on the carvedilol motif toidentify features that correlate with and optimize SOICR inhibition.A single-cell bioassay was employed on the basis of the RyR2-R4496Cmutant HEK-293 cell line in which calcium release from the endoplasmicreticulum through the defective channel was measured. IC50values for SOICR inhibition were thus obtained. The compounds investigatedcontained modifications to the three principal subunits of carvedilol,including the carbazole and catechol moieties, as well as the linkerchain containing the β-amino alcohol functionality. The SARresults indicate that significant alterations are tolerated in eachof the three subunits. [ABSTRACT FROM AUTHOR]

Cyclic seleninate esters serve as catalysts for the rapid oxidation of sulfides to sulfoxides, alkenes to epoxides, and enamines to α-hydroxyketones. Optimal conditions were found that minimize the overoxidation of the product sulfoxides to sulfones and the hydrolysis of epoxides to diols. In some examples such as styrene derivatives, oxidative cleavage was observed instead of epoxidation. The enamine oxidations proceed via the initial formation of dimeric 2,5-diamino-1,4-dioxane species, which were hydrolyzed in situ to the final products. The structure of one such dimer was confirmed by X-ray crystallography [ABSTRACT FROM AUTHOR]