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001-es BibID:	BIBFORM009027
Első szerző:	Polavarapu, Prasad L.
Cím:	Determination of the Absolute Configurations at Stereogenic Centers in the Presence of Axial Chirality / Prasad L. Polavarapu, Neha Jeirath, Tibor Kurtán, Gennaro Pescitelli, Karsten Krohn
Dátum:	2009
Megjegyzések:	In this review article we examine state-of-the-art techniques for the structural elucidation of organic compounds isolated from natural sources. In particular, we focus on the determination of absolute configuration (AC), perhaps the most challenging but inevitable step in the whole process, especially when newly isolated compounds are screened for biological activity. Among the many methods employed for AC assignment that we review, special attention is paid to electronic circular dichroism (CD) and to the modern tools available for quantum-mechanics CD predictions, including TDDFT. In this context, we stress that conformational flexibility often poses a limit to practical CD calculations of solution CD spectra. Many crystalline natural products suitable for X-ray analysis do not contain heavy atoms for a confidential AC assignment by resonant scattering. However, their CD spectra can be recorded in the solid state, for example with the KCl pellet technique, and analyzed possibly by nonempirical means to provide stereochemical information. In particular, solid-state CD spectra can be compared with those calculated with TDDFT or other high-level methods, using the X-ray geometry as input. The solid-state CD/TDDFT approach, described in detail, represents a quick and reliable tool for AC assignment of natural products.
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban absolute configuration conformational analysis X-ray diffractometry TDDFT calculations exciton-coupled CD KCl pellet
Megjelenés:	Chirality. - 21 (2009), p. E202-E207. -
További szerzők:	Jeirath, Neha Kurtán Tibor (1973-) (vegyész, angol szakfordító) Pescitelli, Gennaro (1972-) (vegyész) Krohn, Karsten
Internet cím:	DOI elektronikus változat
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