the treatment equimolar quantities of carboxylic acids with acid chlorides in the presence of zno brings abouthighly efficient unsymmetrical anhydrides at room temperature in solvent-free condition. reactivity trendsfavored formation of the product using both electron deficient and rich aryl acids and acid chlorides.

Unsymmetrical dispiro- and spirotetraoxanes have been designed and synthesized via acid-catalyzed cyclocondensation of bis(hydroperoxides) with ketones. Incorporation of water-soluble and polar functionalities, via reductive amination and amide bond formation, produces several analogues with low nanomolar in vitro antimalarial activity. Several analogues display an unprecedented level of oral a...

This paper describes an enantioselective intermolecular allylic amination catalyzed by a chiral Brønsted acid via a possible chiral contact ion pair intermediate. A variety of symmetrical or unsymmetrical allylic alcohols can be smoothly aminated to afford the desired products in moderate to high yields with good enantioselectivities and/or regioselectivities.

Three new unsymmetrical anthracenyl-pentacene derivatives have been synthesized, characterized using X-ray crystallography, and used as semiconductors in OTFTs. For one derivative, ambipolar charge carrier transport was observed with a hole mobility of 0.2 cm(2) V(-1) s(-1) and an electron mobility of 0.03 cm(2) V(-1) s(-1).

In the title compound, C(21)H(16)N(4)O, the central tetra-zine ring adopts an unsymmetrical boat conformation with the two N atoms as the bow and stern. The crystal packing is stabilized by inter-molecular N-H-O hydrogen bonds.

The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C₂-symmetric a...