Synthesis and Kinetic Study of the Deamination of the Cis Diastereomers of 5,6-Dihydroxy-5,6-dihydro-5-methyl-2‘-deoxycytidine
摘要:
The main objectives of the present work were the synthesis of the two cis diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine and the kinetic study of their hydrolytic deamination. The preparation of the two glycols, two main (OH)-O-.-mediated oxidation products of 5-methyl-2'-deoxycytidine, was achieved in two steps. The first one involved the synthesis of the two trans-(5R,6S)- and (5S,6R)-5-bromo-6-hydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine. In a subsequent step, the bromohydrins were specifically converted into the cis-(5S,6S) and (5R,6R) diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine, respectively, under slightly alkaline conditions. The resulting glycols were purified by reverse phase high performance liquid chromatography and characterized by extensive spectroscopy measurements including C-13- and H-1-NMR analyses. Exact mass determination was Inferred from high resolution fast atom bombardment mass spectrometry measurements. Circular dichroism spectroscopy confirmed the diastereomeric relationship existing between the pair of glycols. Kinetic study of the deamination of the above glycols was carried out in phosphate buffer solutions (pH 7) at two different temperatures (37 degrees C and 25 degrees C) in order to determine the thermodynamic and kinetic parameters of the reaction.
Synthesis and Kinetic Study of the Deamination of the <i>Cis</i> Diastereomers of 5,6-Dihydroxy-5,6-dihydro-5-methyl-2‘-deoxycytidine
作者:Carine Bienvenu、Jean Cadet
DOI:10.1021/jo951900e
日期:1996.1.1
The main objectives of the present work were the synthesis of the two cis diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine and the kinetic study of their hydrolytic deamination. The preparation of the two glycols, two main (OH)-O-.-mediated oxidation products of 5-methyl-2'-deoxycytidine, was achieved in two steps. The first one involved the synthesis of the two trans-(5R,6S)- and (5S,6R)-5-bromo-6-hydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine. In a subsequent step, the bromohydrins were specifically converted into the cis-(5S,6S) and (5R,6R) diastereomers of 5,6-dihydroxy-5,6-dihydro-5-methyl-2'-deoxycytidine, respectively, under slightly alkaline conditions. The resulting glycols were purified by reverse phase high performance liquid chromatography and characterized by extensive spectroscopy measurements including C-13- and H-1-NMR analyses. Exact mass determination was Inferred from high resolution fast atom bombardment mass spectrometry measurements. Circular dichroism spectroscopy confirmed the diastereomeric relationship existing between the pair of glycols. Kinetic study of the deamination of the above glycols was carried out in phosphate buffer solutions (pH 7) at two different temperatures (37 degrees C and 25 degrees C) in order to determine the thermodynamic and kinetic parameters of the reaction.
Photo-sensitized formation of the cis-(5R, 6R) diastereomer of 5,6-dihydroxy-5,6-dihydro-5-methyl-2’-deoxycytidine
作者:C Bienvenu、C Lebrun、J Cadet
DOI:10.1051/jcp/1997940300
日期:——
The 5,6-dihydroxy-5,6-dihydro-5-methyl-2’-deoxycytidine is an oxidation product formed by hydroxyl radical (•OH). The same product has been obtained by menadione photosensitization of 5-methyl-2’-deoxycytidine (m5dCyd). 18O labeling experiments led us to suggest a mechanism for the photosensitized formation of 5,6-dihydroxy-5,6-dihydro-5-methyl-2’-deoxycytidine involving initial generation of the m5dCyd radical cation.