Spirocyclopropanes: Only one out of eight possible stereoisomers was obtained in the asymmetric cascade cyclopropanation of alkylidene oxindoles with ethyl 2-chloroacetoacetate. Improved catalyst design ensured that spirocyclopropyl oxindoles featuring two quaternary centers were synthesized in high yield and high enantio- and diastereoselectivity (see scheme).
Cyclodextrins are usually used in antifungal formulations as auxiliary substances to improve solubility, stability, or other physicochemical properties of the active compound. Nevertheless, more and more research and practical use results indicate that cyclodextrins might also act as active compounds in pharmaceutical formulations. The biological effects of cyclodextrins, important for their use within antimycotic formulations, can be divided into: effects based on the ability of cyclodextrins to form inclusion complexes with endogenous substances (membrane lipids, cellular cholesterol), effects based on formation of inclusion complexes with component parts of fungi cells, and effects based on the chemical nature of cyclodextrins and their derivatives. This review will cover the advances in research of biological activity of cyclodextrins with focus on their properties responsible for their synergistic effect with antimycotic compounds.
Abstract:The paper presents an application of the asymmetry approach to spirooxindoles via Brevicolline, Cinchonidine or Cinchonine catalyzed one-pot multicomponent synthesis. Brevicolline, in comparison with Cinchonidine or Cinchonine, catalyzes the reaction of isatins, acetylacetone/ethyl 3-oxobutanoate and malononitrile, with the formation of spiro [oxindole-3,4'-4'H-pirane] derivatives in an optically active form in very good to excellent yields.
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