ホウ酸塩によるPurine Nucleoside類の可溶化とその機構 : N-ヘテロ芳香族の電子的性状 第29報

抄録

Adenosine and inosine were found to be solubilized markedly in 1 : 1 mixed aqueous solution of boric acid and sodium hydroxide. Guanosine, when added in high concentration, was gelatinized in the same solution. 2', 3'-O-Isopropylideneadenosine was not solubilized. In the case of adenosine and inosine, formation of soluble complexes of 2 : 1 : 1 (nucleoside-H₃BO₃-NaOH) molar ratio was ascertained through solubility measurements. The results of electric conductance measurements indicated formation of 2 : 1 complexes of nucleoside (adenosine or inosine) and boric acid. The pH-titration curves revealed that chelate compounds in which boric acid is bound to the sugar moieties of nucleosides were formed. Overall formation constants of chelation in acid and alkaline solutions were determined. Ionization constant of adenosine-boric acid chelate was also determined, which was in good accord with that of D-ribose-boric acid chelate. Two crystalline chelates were separated from acid and alkaline mixed solutions of adenosine and boric acid. The infrared spectrum of acid crystalline chelate was quite similar to that of 2', 3'-O-isopropylideneadenosine. Other analytical data such as elemental analysis, ultraviolet absorption, and solubility data were also consistent with those obtained in solution.