Comparison of symptomatic and neurophysiological activities of enantiomers of the insecticide 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropane‐1‐carboxylate

Abstract

The insecticidal activities of optical isomers of 3‐phenoxybenzyl 1‐(4‐ethoxyphenyl)‐2,2‐dichlorocyclopropanecarboxylate and related compounds were measured with American cockroaches and their knockdown activities were evaluated with house flies. The activities of the S(−)‐isomer of the dichlorocyclopropanecarboxylate were higher than those of the R(+)‐isomer. The effects of the compounds on the inward membrane currents induced by a stepdepolarizing pulse in crayfish axonal membranes were examined under voltage clamp conditions by the sucrose gap method. The compounds induced a tail current upon step repolarization of the membrane. The tail current decayed to zero in each record, but developed with time after the start of application of the compound until a steady level was reached. The rate of decay of the tail current observed in axonal membranes treated with the S(−)‐isomer was slower than with the R(+)‐isomer. The rates of development of the tail current induced by the two isomers were not very different.

Three-Dimensional Structure-Activity Relationships of Synthetic Pyrethroids: 1. Similarity in Bioactive Conformations and Their Structure-Activity Pattern

“…Relat., 19 (2000) diastereomers IV H and VI H , respectively. The 1S-enantiomer VIII of Cl 2 -cyclopropne-ester is more active than its 1R-isomers [9]. For the F 4 -cyclobutane-ester, the 1S form VII was assumed to be more active than the R form [9].…”

“…The 1S-enantiomer VIII of Cl 2 -cyclopropne-ester is more active than its 1R-isomers [9]. For the F 4 -cyclobutane-ester, the 1S form VII was assumed to be more active than the R form [9]. The activity of phenothrin diastereomers V and V H is, however, nearly equivalent [10,11].…”

Three-Dimensional Structure-Activity Relationships of Synthetic Pyrethroids: 2. Three-Dimensional and Classical QSAR Studies

“…For Series III and IV, the log(1yMLD) value is that measured with the racemic compounds. Because the 1S isomers are believed much more active than the 1R form [9], the activity indices could be corrected by adding 0.3 ( log 2).…”