Separation of rotamers of 5-nitrosopyrimidines and estimation of binding constants of their complexes with beta-cyclodextrin by capillary electrophoresis

0495254 - ÚOCHB 2019 RIV NL eng J - Článek v odborném periodiku
Štěpánová, Sille - Procházková, Eliška - Čechová, Lucie - Žurek, Jiří - Janeba, Zlatko - Dračínský, Martin - Kašička, Václav
Separation of rotamers of 5-nitrosopyrimidines and estimation of binding constants of their complexes with beta-cyclodextrin by capillary electrophoresis.
Journal of Chromatography A. Roč. 1570, Oct 5 (2018), s. 164-171. ISSN 0021-9673. E-ISSN 1873-3778
Grant CEP: GA ČR(CZ) GA17-10832S; GA ČR(CZ) GA18-02597S
Institucionální podpora: RVO:61388963
Klíčová slova: affinity capillary electrophoresis * binding constant * capillary electrophoresis * cyclodextrins * 5-nitrosopyrimidines * planar rotamers
Obor OECD: Analytical chemistry
Impakt faktor: 3.858, rok: 2018

For the first time, capillary electrophoresis has been successfully employed for the fast and highly efficient separations of a novel type of stereoisomers - planar rotamers (planamers) of four newly synthesized 5-nitrosopyrimidine derivatives. These derivatives can form two rotamers differing in the orientation of nitroso group due to strong intramolecular hydrogen bonds. Partial separation of rotamers of two 5-nitrosopyrimidines was achieved in alkaline 50 mM sodium tetraborate, pH 9.3, and in acidic 18.5/42 mM Tris/phosphate, pH 2.3, background electrolytes (BGEs) free of stereoselectors. To improve the separation of these rotamers and to attain the baseline or better separation of rotamers of other two 5-nitrosopyrimidines, various BGEs and different cyclodextrins-based stereoselectors were tested. The most effective, i.e. the fastest and baseline or better separations of rotamers of all analyzed 5-nitrosopyrimidines were achieved within a short time, 3.7-9.3 min, in the above alkaline or acidic BGEs using beta-cyclodextrin (beta-CD) or carboxymethyl-beta-CD as stereoselectors. Moreover, since the experiments with beta-CD resulted in good separations of rotamers of all the investigated 5-nitrosopyrimidines, the apparent binding constants of their complexes with this selector were determined from the dependence of their effective mobilities on the beta-CD concentration in the BGEs. The examined complexes were found to be relatively weak, with the apparent binding constants in the range 11.3-153.0 L/mol.
Trvalý link: http://hdl.handle.net/11104/0288255