キサンチン誘導体の分子化合物形成に関する研究 (第1報)

カフェインに対する置換安息香酸ナトリウム塩類の溶解補助作用

抄録

Solubilizing action of the sodium salt of benzoic acid, o-, m-, and p-hydroxy-, methoxy-, amino-, nitro-, and chloro-benzoic acid, and nicotinic acid on caffeine was determined and the effect of the kind and position on the solubilization was examined. The solubilizing action was found to be in the descending order, in molar equivalent of the salt, of salicylate≅m-chloro-, p-chloro-, m-hydroxy-≅p-hydroxy-≅m-methoxy-≅p-methoxy-, m-nitro-, p-nitro-, o-amino-, and p-amino-benzoate, benzoate, m-aminobenzoate, nicotinate, and o-chloro-, o-methoxy-, and o-nitro-benzoate. The solubilizing action of these benzoates is assumed to be not due to formation of a complex of established composition but due to the formation of a hydrogen bond between caffeine and benzoate, with the water molecule of the solvent acting as the hydrogen-bond donor.