A new stereoselective approach to aminocyclohexitols using RCM

rac- and meso-Cyclohexanoids: Their α-, β-glycosidases, antibacterial, antifungal activities, and molecular docking studies

An efficient and versatile synthesis method has been postulated for hydroxymethylated rac- and meso-cyclohexanoid derivatives. The synthesis of these stereoisomers was achieved easily with traditional methods using hexahydroisobenzofuran 6, prepared from commercially available cis-hydrophthalic anhydride. The study, involving diastereoselective epoxidation and cis-hydroxylation, was conducted to obtain epoxy-, cis-, and trans-diol-furans 7, 8, and 9. After sulfamic acid-catalyzed ring-opening reaction of the epoxide and furan rings, rac- and meso-tetraacetates 14, 15, and 16 were afforded. Hydrolysis of acetate groups with ammonia in absolute methanol yielded the desired tetrols rac-17, meso-18, and meso-19. All structures, after purification by chromatographic methods and elucidation by spectral techniques, were screened against α- and β-glucosidases. Compounds 7, 8, 10, 17, 18, and 19 were also evaluated for their antibacterial and antifungal activity against some selected synthesized compounds with varying degrees of inhibitory effects on the growth of different pathogenic microorganisms by the well-diffusion method. In addition, Saccharomyces cerevisiae α-glucosidase molecular modeling studies were performed for all rac- and meso-compounds 7, 8, 10, 17, 18, and 19.

Stereoselective synthesis of new rac-quercitols containing hydroxymethyl groups as glucosidase inhibitors

Stereoselective and efficient synthesis of hydroxymethyl-substituted rac-quercitols (13-15) was achieved, starting from cis-furan (Kobayashi, 2008) with photooxygenation reaction, which is readily available by the reduction of cis-phtalic anhydride. α- and β-Glucosidase enzyme activity of the target molecules was evaluated and good inhibitor activity was seen. One- and two-dimensional NMR spectroscopy, IR spectroscopy and X-ray crystallography were utilized in the structure characterization of products.

Simple Indolizidine and Quinolizidine Alkaloids

This review of simple indolizidine and quinolizidine alkaloids (i.e., those in which the parent bicyclic systems are in general not embedded in polycyclic arrays) is an update of the previous coverage in Volume 55 of this series (2001). The present survey covers the literature from mid-1999 to the end of 2013; and in addition to aspects of the isolation, characterization, and biological activity of the alkaloids, much emphasis is placed on their total synthesis. A brief introduction to the topic is followed by an overview of relevant alkaloids from fungal and microbial sources, among them slaframine, cyclizidine, Steptomyces metabolites, and the pantocins. The important iminosugar alkaloids lentiginosine, steviamine, swainsonine, castanospermine, and related hydroxyindolizidines are dealt with in the subsequent section. The fourth and fifth sections cover metabolites from terrestrial plants. Pertinent plant alkaloids bearing alkyl, functionalized alkyl or alkenyl substituents include dendroprimine, anibamine, simple alkaloids belonging to the genera Prosopis, Elaeocarpus, Lycopodium, and Poranthera, and bicyclic alkaloids of the lupin family. Plant alkaloids bearing aryl or heteroaryl substituents include ipalbidine and analogs, secophenanthroindolizidine and secophenanthroquinolizidine alkaloids (among them septicine, julandine, and analogs), ficuseptine, lasubines, and other simple quinolizidines of the Lythraceae, the simple furyl-substituted Nuphar alkaloids, and a mixed quinolizidine-quinazoline alkaloid. The penultimate section of the review deals with the sizable group of simple indolizidine and quinolizidine alkaloids isolated from, or detected in, ants, mites, and terrestrial amphibians, and includes an overview of the "dietary hypothesis" for the origin of the amphibian metabolites. The final section surveys relevant alkaloids from marine sources, and includes clathryimines and analogs, stellettamides, the clavepictines and pictamine, and bis(quinolizidine) alkaloids.

Iminosugar-ferrocene conjugates as potential anticancer agents

We prepared a series of new iminosugar-ferrocene hybrids displaying potent inhibition of fucosidase (bovine kidney) and inactivation of MDA-MB-231 breast cancer cells proliferation at low micromolar concentrations. The synthetic route brought to light an unprecedented isomerisation of a 2-ethanalylpyrrolidine.