No abstract

Quantitative structure‐activity relationship (QSAR) studies have been carried out on oral rat LD50 values, for 129 herbicidal (trifluoromethyl)benzimidazoles, by multiple regression analyses, using computer‐generated descriptors to represent chemical structure, at several levels of specificity. The results permit rationalisation of the structure‐toxicity relationship, particularly the effect of substituent interactions, and allows reliable ‘rough estimate’ prediction of toxicity. However, reliable predictions of high accuracy are not feasible, even from analysis of this large, consistent, congeneric set of data, thus casting doubt on the suitability of the LD50 as a biological end‐point for a QSAR.

No abstract

The two criteria which a pesticide screening programme should satisfy are firstly to select economically active compounds for full scale field trials and secondly to provide guidance for the planning of future chemical synthesis. In order to fulfill the second of these functions it is necessary to analyse in depth the relationships between chemical structure and biological activity. This procedure which may involve the correlation of large volumes of data can be facilitated considerably by the use of computer based techniques which are described and discussed.

A series of trialkyland triarykin heterocyclic sulphides were prepared and tested for pesticidal activity . In general the tripropyl-and tributyltin derivatives possessed the highest potencies but the heterocyclic moiety had little effect on activities. a Distilled yield b Slight decomposition Crystallised from ethanol I( 7 0Thiol hydrochloride used as reactant