title: Determination of the absolute configuration of flexible molecules by ab initio ORD calculations: a case study with cytoxazones and isocytoxazones.
abstract: 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.
authors.affiliation: Dipartimento di Chimica, Università della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy.
authors.forename: Egidio
authors.initials: E
authors.lastname: Giorgio
authors.forename: Marin
authors.initials: M
authors.lastname: Roje
authors.forename: Katsunori
authors.initials: K
authors.lastname: Tanaka
authors.forename: Zdenko
authors.initials: Z
authors.lastname: Hamersak
authors.forename: Vitomir
authors.initials: V
authors.lastname: Sunjic
authors.forename: Koji
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Carlo
authors.initials: C
authors.lastname: Rosini
authors.forename: Nina
authors.initials: N
authors.lastname: Berova
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D010080:Oxazoles; C117832:cytoxazone