Ab initio calculations of the optical rotatory power of the natural cytokine modulator cytoxazone 1 and its trans-diastereomer 2, as well as the structural isomers cis-3 and trans-4 isocytoxazones, have been performed at four different wavelengths (589, 546, 435, and 405 nm) by Density Functional Theory. The calculation of ORD curves provides a reliable method for the assignment of absolute configuration of these conformationally flexible molecules. The absolute configurations of isocytoxazones has been established as (+)-(4R,5S)-cis-3 and (+)-(4S,5S)-trans-4.

New series of dimeric molecules with flexible spacers are described in which the mesogenic salicylaldimine group is linked to the alkylene spacer via an imino group. To study the structure−property relations, the lengths of the alkylene spacers (m = 5−8) as well as those of the terminal alkoxy chains (n = 4−14) have been varied. The compounds with even-numbered spacers behave as classic rodlike mesogens displaying nematic and/or smectic C phases, while those with odd-numbered spacers show nematic, columnar nematic, and columnar rectangular phases, behaving as bent-core mesogens. The effect on the liquid-crystalline behavior of the effective geometric change arising from the spacer parity and the imino linkage is discussed.

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Poly[2-methoxy-5(2′-ethylhexoxy)-p-phenylenevinylene] (MEH-PPV) has been for the first time prepared and fully characterized in enantiopure (R) form. If the polymer molecular weight is sufficiently low, (R)-MEH-PPV assumes a helical supramolecular structure in the solution aggregates, with consequences on the tendency to aggregation and on the fluorescence quenching, both of which are reduced with respect to the racemic analogue.

An efficient dynamic kinetic resolution protocolu sing as ingle enzyme is described. Both the kinetic resolution and substrate racemization are catalyzed by halohydrin dehalogenase from Agrobacterium radiobacter AD1 (HheC). The HheC-catalyzed reactiono fe pibromohydrin and 2bromomethyl-2-methyloxirane with sodium cyanate afforded 5-substituted 2-oxazolidinones in high yields (97% and 87%) and high optical purity( 89% and > 99% ee)i nt he presence of catalytic amounts of bromide ion. Thesec ompounds are valuable building blocks with diverse synthetic applications.

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