Structure–activity relationship (SAR) study of some aliphatic and aromatics carboxyl– and α–amino–C–phosphonates congeneric esters and Schiff derivatives using a developed Köln–model (Hydractinia echinata Toxicity Screening Test System. VI.)

Abstract

The toxicity development process of the studied Carboxylic− (R1–[C(O)–OR2]n) (n = 1–4), and α–Amino–C–Phosphonates ({R1–CH[(O)P(OR2)2]}n–R3) (n = 1–2) esters is based on the Congenericity Principle and is quantified by the measured values (Mes) using the scientifically developed Köln–Model and Hydractinia echinata Toxicity Screening Test System (HeTSTS). The process consists of two successive steps: i) hydrolysis of the esters in the seawater alkaline medium (pH 8.2) with the formation of the xenobiotic substrate (SbX) consisting of the binary acid–alcohol mixture and ii) their interaction with the cellular receptors (R). In both series of esters, the results indicate, within the combination of the electronic effects, the steric effects, the possible hydrogen bonds, and so on, the clear and well–defined influence of the number of alcoholic carbon atoms (R2) on the Mes values as Class Regulated Increased Toxicity. The approach was also successfully applied and confirmed by published data in what concerns the similarly carboxylic esters for the ciliate protozoan Tetrahymena pyriformis (T. pyriformis) and the freshwater fish Pimephales promelas (P. promelas) as Toxicity Screening Tests Systems (Tp–PpTSTS’s). Based on this research model, there is a possibility of making predictions of toxicity values with respect to these systems for substances not tested yet. Since the hydrolysis of natural or anthropogenic esters requires an important solvation of the formed ions, its importance to its aquatic surrounding environment is directly due to the action of the reaction products.