Methylation of Deoxynucleotides with Trimethyl Phosphate in Aqueous Phase

Abstract

Abstract Action of trimethyl phosphate on thymidine 5′-phosphate, deoxycytidine 5′-phosphate, deoxyadenosine 5′-phosphate, and deoxyguanosine 5′-phosphate at 37–60 °C, and pH 7–10 gave their methyl esters and base-methylated derivatives. Esterification took place in all deoxyribonucleotides to the almost same extent and its rate was enhanced by the reaction temperature, while being independent of pH in the range 7–10. On the other hand, methylation of the base moieties was affected by both the reaction temperature and pH of the reaction medium. The reactivity order of the four kinds of base moieties w s; at pH 7, cytosine base (N-3)>guanine base (N-7)>adenine base (N-1)>>thymine base (N-3); at pH 10, thymine base (N-3)>guanine base (N-1>N-7)>cytosine base (N-3)>adenine base (N-1).