Ari M. P. Koskinen

Catalytic Activity Dependency on Catalyst Components in Aerobic Copper-TEMPO Oxidation

The influence of catalyst components in the copper-TEMPO (2,2,6,6-tetramethylpiperidine N-oxide) catalysed aerobic oxidation of alcohols was investigated. The type and amount of base greatly influences reactivity. The bipyridyl ligand concentration had no major influence on catalysis, but excessive amounts led to a decrease in activity for longer reaction times. The kinetic dependency for TEMPO was found to be 1.15, and for copper 2.25, which is an indication of a binuclear catalytic system. Optimised conditions with various allylic and aliphatic alcohols give good to excellent rapid oxidations.

Asymmetric Organocatalytic Diels-Alder Reactions on Solid Support

Asymmetric organocatalysis on solid support combines the environmental advantages of metal-free catalysts and the ease of operation of solid-supported reagents. Enantioselective organocatalytic DielsAlder reactions have been demonstrated by two different solid-supported chiral organocatalysts. The catalysts are easy to recover and they can be reused. The reactivity of the catalyst can be tuned by changing the solid support.

Conversion of carbonyl compounds to alkynes: general overview and recent developments

The preparation of alkynes from carbonyl compounds via a one-carbon homologation has become a very useful pathway for the synthesis of acetylenic compounds, both internal and terminal. This tutorial review provides an overview of the different methods available for this transformation, including their scope and limitations, recent developments and applications in total syntheses.

Synthetic Approaches towards Indoles on Solid phase - Recent Advances and Future Directions

Powered by TCPDF (www.tcpdf.org) This material is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. Tois, J.; Franzen, R.; Koskinen, A.M.P.

A novel linkage for the solid-phase synthesis of hydroxamic acids

Abstract A novel linkage for the solid-phase synthesis of hydroxamic acids is described and its facile application for the solid phase synthesis of peptidyl, succinyl and urea-type hydroxamic acids is illustrated. Cleavage is induced under mild acidic conditions by treatment with formic acid in THF, providing hydroxamic acids in high purity and fair to good yields.

Synthesis of quinolinyl and isoquinolinyl phenyl ketones as novel agonists for the cannabinoid CB2 receptor

A series of quinolinyl and isoquinolinyl phenyl ketones was synthesized and their CB(2) receptor-dependent G-protein activities were determined using the [(35)S]GTPgammaS binding assay. Both quinoline and isoquinoline derivatives exhibited similar CB(2) receptor agonist activity, the most potent ligands being the 2-(Me(2)N)-phenyl substituted derivatives, which were also full agonists at the CB(2)-receptor.

Co(II) Catalysed Oxidation of α-Pinene by Molecular Oxygen. Part 2

Abstract This paper reports studies of factors affecting air oxidation of (−)-α-pinene catalysed by Co(II)–pyridine complexes without a concomitant co-oxidant. Observations are presented about the nature and amount of the catalyst, reaction temperature, oxygen flow and solvent vs. non-solvent conditions. In addition, attention has been paid to the influence of added base or acid, and identification of side products.

Calyculins and Related Marine Natural Products as Serine-Threonine Protein Phosphatase PP1 and PP2A Inhibitors and Total Syntheses of Calyculin A, B, and C

Calyculins, highly cytotoxic polyketides, originally isolated from the marine sponge Discodermia calyx by Fusetani and co-workers, belong to the lithistid sponges group. These molecules have become interesting targets for cell biologists and synthetic organic chemists. The serine/threonine protein phosphatases play an essential role in the cellular signalling, metabolism, and cell cycle control. Calyculins express potent protein phosphatase 1 and 2A inhibitory activity, and have therefore become valuable tools for cellular biologists studying intracellular processes and their control by reversible phosphorylation. Calyculins might also play an important role in the development of several diseases such as cancer, neurodegenerative diseases, and type 2-diabetes mellitus. The fascinating structures of calyculins have inspired various groups of synthetic organic chemists to develop total syntheses of the most abundant calyculins A and C. However, with fifteen chiral centres, a cyano-capped tetraene unit, a phosphate-bearing spiroketal, an anti, anti, anti dipropionate segment, an α-chiral oxazole, and a trihydroxylated γ-amino acid, calyculins reach versatility that only few natural products can surpass, and truly challenge modern chemists’ asymmetric synthesis skills.

Co(II)-catalysed allylic oxidation of α-pinene by molecular oxygen; synthesis of verbenone

Abstract A facile, high-yield, catalytic air-oxidation entry to verbenone (2) from α-pinene (1) is presented.

Pharmacological importance of optically active tetrahydro-β-carbolines and synthetic approaches to create the C1 stereocenter.

1,2,3,4-Tetrahydro-β-carbolines (THβCs) are a pharmacologically important group of compounds belonging to the indole alkaloids. C1-Substituted optically active THβCs have been the target of extensive synthetic efforts due to the presence of the scaffold in numerous natural products and synthetic targets. This review briefly summarizes the methods to obtain the C1 stereocenter and concentrates on evaluating the pharmacological importance of optically active C1-substituted THβCs, including their PDE5-inhibitory, antimalarial, antiviral and antitumor activities.