Physico-chemical properties of barbituric acid derivatives: IV. Solubilities of 5,5-disubstituted barbituric acids in water

Abstract

Solubilities at 25°C in 0.001 M HC1 were determined for a series of 29 barbituric acid derivatives with aliphatic or aromatic substituents. The range of solubilities spanned more than four orders of magnitude. Relationships between these solubilities and other structural and physico-chemical properties were investigated. The data were fitted to a predictive relationship between solubility (as dependent variable) and the melting points and partition coefficients first proposed by Yalkowsky. The predicted solubilities from this relationship were in very good agreement with the measured values for some derivatives. A few solubilities deviated significantly. Data for several 5-methyl substituted barbituric acid derivatives suggested that they are more hydrated in aqueous solution than the corresponding 5-ethyl derivatives. © 1994.