The absolute configuration of polycephalin C from the slime mold Physarum polycephalum (Myxomycetes)

Naturally occurring tetramic acid products: isolation, structure elucidation and biological activity

Natural products containing the tetramic acid core scaffold have been isolated from an assortment of terrestrial and marine species and often display wide ranging and potent biological activities including antibacterial, antiviral and antitumoral activities.

Secondary metabolites of slime molds (myxomycetes)

The compounds reported from the slime molds (myxomycetes) species are described. Almost 100 natural compounds including their chemical structures and biological activities are described in this review article. Only metabolites with a well-defined structure are included.

Synthesis, structure, and contrasting chiroptical properties of large trianglimine macrocycles

We have synthesized a number of large trianglimine macrocycles (3a-3f) using our methodology of (3+3) cyclocondensation of (R,R)-trans-1,2-diaminocyclohexane (1) with rigid aromatic dialdehydes (2a-2f), having benzene, biphenyl, terphenyl, styrene, or divinylbenzene spacers. The structures of these chiral macrocycles have been analyzed using computational methods as well as CD spectroscopy. Whereas trianglimines 3a-3d gave uniformly negative exciton Cotton effects, as expected, styrene- and divinylbenzene-based trianglimines 3e and 3f gave opposite-sign exciton Cotton effects. Their contrasting CD behavior was traced by computational methods to subtle differences in the relative orientation of the electric dipole transition moments in the chromophores of the trianglimines. The presence of low-intensity long-wavelength electronic transitions having large rotational strengths in the electronic spectra of 3e and 3f can be accounted for by the symmetry properties of the trichromophoric macrocycles.

Enzymatic catalysis of the Diels–Alder reaction in the biosynthesis of natural products

Recent studies on enzymes catalyzing the Diels- Alder reaction. often named "Diels-Alderases", clearlydemonstrated the involvement of this synthetically useful reaction in the biosynthesis of natural products.This review covers natural Diels-Alder type cycloadducts. synthetic efforts on the chemical feasibility ofthe biosynthctic Diels - Alder reaction and a brief history of studies on Diels-Alderases. In addition,reaction mechanisms of artificial and natural Diels--Alderases are discussed.