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Absolute Configurations of L-Ascorbic Acid Derivatives: Circular Dichroism and X-Ray Crystal Structure Studies


Wittine, Karlo; Gazivoda, Tatjana; Markuš, Marko; Mrvoš-Sermek, Draginja; Hergold-Brundić, Antonija; Nagl, Ante; Žiher, Dinko; Gabelica, Vesna; Mintas, Mladen; Raić-Malić, Silvana
Absolute Configurations of L-Ascorbic Acid Derivatives: Circular Dichroism and X-Ray Crystal Structure Studies // 2nd Chemical European Chemical Meeting
Varaždin, Hrvatska, 2003. (poster, nije recenziran, sažetak, znanstveni)


Naslov
Absolute Configurations of L-Ascorbic Acid Derivatives: Circular Dichroism and X-Ray Crystal Structure Studies

Autori
Wittine, Karlo ; Gazivoda, Tatjana ; Markuš, Marko ; Mrvoš-Sermek, Draginja ; Hergold-Brundić, Antonija ; Nagl, Ante ; Žiher, Dinko ; Gabelica, Vesna ; Mintas, Mladen ; Raić-Malić, Silvana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
2nd Chemical European Chemical Meeting / - , 2003

Skup
2nd Chemical European Chemical Meeting

Mjesto i datum
Varaždin, Hrvatska, 19-21.06.2003

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
L-ascorbic acid derivatives; Single crystal X-ray diffraction; Circular dichroism spectroscopy; Cotton effect

Sažetak
The present study deals with the chiral 2, 3-O, O-dibenzyl derivatives of L-ascorbic acid containing 4-(5, 6-epoxy)- (4), 6-O-tosyl- (8) and 5, 6-O, O-ditosyl- (9) functional groups and it was undertaken to determine the absolute configuration of these compounds which is of importance for elucidation of stereochemical course of their condensation reaction with nucleoside bases and evaluation of their biological properties. X-ray crystal structure analysis using anomalous dispersion gave the exact stereostructures of 2, 3-O, O-dibenzyl-5, 6-isopropylidene-L-ascorbic acid (6) and 8. The comparison of the CD spectra of 4, 8 and 9 with the CD spectra of their synthetic precursors (2-3, 5-7) and L-ascorbic acid (1) itself, as well as crystal structures of 6 and 8 permitted the assignment of the absolute configurations of 4 and 9. Thus, it was found that C-4 and C-5 in 4 and 9 have R- and S- configurations. This means that the syntheses of 4, 8 and 9 proceeded from the starting L-ascorbic acid by retention of configuration.

Izvorni jezik
Engleski

Znanstvena područja
Kemija