Synthesis and insecticidal activity of 4-perhaloalkoxy (or thioalkyl) benzophenonehydrazone derivatives

Abstract

from both ExpF-based treatments were almost identical.Not all xylem-mobile molecules behave in the same way and this is illustrated by a comparison between ExpF and¯uquinconazole when both were mixed with Adj1. Fluquinconazole was recovered only in very small quantities, the single greatest recovery being 0.17% over a 24 h period. These recoveries are considerably less than those already described for ExpF when mixed with the same adjuvant. That recovery in guttation¯uid is not solely related to the level of uptake into the plant is supported by data from other experiments (Harris RI unpublished) where the uptakes of both¯uquinconazole and ExpF were very similar when mixed with Adj1 (60 and 69%, respectively, 24 h after application).Using ExpF as a model compound it should be possible to investigate the behaviour of other formulation systems on target crops. A speci®c example of the use of this system is the evaluation of encapsulated formulations. It is possible to prepare capsules with a range of properties, one of these being ease of capsule breakdown, resulting in the release of the encapsulated compound. This can be monitored using arti®cial surfaces, but there is now the possibility of doing studies in vivo using the model described above.Information about the loss of fungicide, insecticide and herbicide molecules in guttation¯uid can also help explain biological performance against target species. For example, the activity of ExpF against Erysiphe graminis DC f sp tritici Marchal, (the causal organism of powdery mildew of wheat) was enhanced when mixed with Adj2 but not Adj1 (Moss, N A pers. comm.). From the results discussed above it is possible that a biologically signi®cant proportion of the applied dose of ExpF, when mixed with Adj1, was lost through guttation, resulting in an inferior performance compared with the mixture with Adj2. Life-cycle studies showed ExpF to be more effective as a protectant than curative fungicide and that the early stages of pathogen development were most affected. A formulation optimising surface retention rather than foliar uptake would, therefore, be more appropriate. Synthesis and insecticidal activity of 4-perhaloalkoxy (or thioalkyl) benzophenonehydrazone derivativesDieter Dürr, Laurenz Gsell, Roger G Hall, Friedrich Karrer, Alfons Pascual* and Alfred Rindlisbacher Novartis Crop Protection AG, PO Box, 4002 Basel, Switzerland Abstract: Benzophenonehydrazone derivatives containing a mesylate or tri¯ate substituent are known to exhibit insecticidal activity. In the present study, such substituents have been replaced by perhaloalkoxy groups. High levels of activity against lepidopteran pests were observed in greenhouse trials. For optimum activity, the substituents should be relatively small. In semi-®eld trials, however, none of the compounds tested showed suf®cient persistence to warrant further development.

Synthesis and structure-activity relationships of benzophenone hydrazone derivatives with insecticidal activity

“…Table 4 lists the biological activity of selected compounds 11 bearing perhaloalkoxy substituents. A detailed account of the influence of the substituents R 1 and R 2 as well as halogen substitution for chlorine where Y = OCF 3 and Y = OCF 2 Br upon the biological activity has already been given,16 so that an overview of representative Y‐substitutions suffices. Small groups R 1 and R 2 together with groups Y = OCF 2 Br and Y = OCF 2 Cl gave the best results.…”

“…Freonisation of 4‐chloro‐4′‐hydroxybenzophenone with CF 2 Br 2 ,15, 16, 30 BrCF 2 CF 2 Br,31 or CF 2 = CF 2 led to the intermediate benzophenones 30b , 30e and 30f ; treatment with ClCF 2 CONH 2 gave 30d in low yield. The introduction of the OCF 3 group was achieved via Grignard reaction of benzonitrile 29 ,15, 16 whereas a one‐pot procedure32 (fluorination in HF of 31 followed by Friedel–Crafts reaction in the presence of BF 3 ) allowed the preparation of intermediate 30c . Finally, compounds 11h and 11i were obtained through oxidation of 11g with m ‐CPBA.…”

“…In the course of our optimisation programme we discovered several modifications10–15 of the original structures with improved biological properties. A short summary of part of this work has been published recently 16…”

An Efficient Synthesis of N'',N'''-Bis[(E)-phenylmethylidene]carbonic Dihydrazide Derivatives and Their Evaluation as α-Chymotrypsin Inhibitors

“…e.g. triethylamine, sulfuric acid, hydrochloric acid, TiCl 2 , Mg(ClO 4 ) 2 and ZnCl 2 (Lefebvre et al, 2010;Durr et al, 1999;Starkov et al, 2017;White & Weingarten, 1967;Chakraborti et al, 2004;Billman & Tai, 1958). Some of these methods suffer from shortcomings such as tedious work-ups and low yields, use of special and costly catalysts.…”

Copper-Mediated Oxidative Chloro- and Bromodifluoromethylation of Phenols

“…Fluoroalkyl ethers are valuable structural motifs in the development of new pharmaceuticals, agrochemicals, and materials because the incorporation of fluoroalkoxy groups into organic compounds often alters their physical, chemical, and pharmacokinetic properties . Among these fluoroalkyl ethers, recently chloro- and bromodifluoromethyl aryl ethers (ArOCF 2 X, X: Cl, Br) are increasingly found as important moieties in biologically active compounds (Figure ) , because of the strength of their halogen bond interactions and their unconventional interaction geometries . For example, asciminib was approved by the FDA in 2021 as a BCR-ABL1 allosteric inhibitor .…”