Mono-substituted p-tert-butylthiacalix[4]arene: Regioselective Synthesis and Toxicological Activity Against Cowpea Aphid, Aphis craccivora (Koch)

Abstract

Tetraethylamonium bromide (TEAB) in dry benzene has been utilized as the base enabling Phase Transfer Catalysis PTC for the synthesis of some novel mono-substituted thiacalix[4]arene 2 and 3 at the lower rim from 2-chloro(p-tolyl)acetamide and 2-chloro(p-acetylphenyl)acetamide, respectively. Bromine and mono-p-acetylphenylacetamide-p-tert-butylthiacalix[4]arene 3 were reacted in chloroform under solar radiation to give mono-p-phenacylbromideacetamide-p-tert-butylthiacalix[4]arene 4. Derivatives of mono-substituted thiacalix[4]arenes 2-4 were reacted with Lawesson reagent (LR) affording mono-substituted thiacalix[4]arene derivatives 5-7, respectively. The temple of the novel compounds was illustrated based on elemental analyses, 1H-, 13C-, and Dept-NMR spectroscopy. Synthesized derivatives have been tested against adult and nymph Cowpea Aphid (Aphis craccivora) in laboratory conditions as insecticidal agents. to calculate the LC50 values for each one of them. Bioassay experiments showed that synthesized compounds 4 and 7 possess the highest insecticidal bio-efficacy, with LC50 values of 1.16 and 2.08 ppm, respectively against nymphs, and 11.96 and 13.52 ppm, respectively, against adults of Aphis craccivora.