Design and development of novel insect growth regulators: Synthesis, characterization and effect of benzoyl thymyl thioureas and ureas on total haemocyte count ofDysdercus koenigii

Abstract

Insect-growth regulators (IGRs) have been receiving foremost attention as potential means of selective insect control. Benzoyl phenyl urea (BPU) is a well-known IGR having chitin synthesis inhibitor activity. Mimics of BPU have been synthesized by suitable derivatization of a naturally occurring monoterpenoid, thymol (2-isopropyl-5-methyl phenol) to form a = series of substituted benzoyl thymyl thioureas (BTTUs) [IVa-f] and benzoyl thymyl ureas (BTUs) [Va-f]. The synthesized compounds have been characterized by (1)H and (13)C NMR, LC-MS and elemental analysis. These derivatives have been screened for their effect on total haemocyte count of Dysdercus koenigii. It has been observed that the introduction of substituted benzoyl thiourea and urea linkage into a thymol ring via an amino group results in higher activity than the parent compound thymol and a comparable pattern of results with the standard insect-growth regulators, Penfluron. Urea [Va-f] compounds exhibited greater effect on Total Haemocyte Count (THC) than thiourea [IVa-f]. Fluoro substitution enhanced the effect on THC more than chloro substituted compounds, while ortho-substitution resulted in a better effect than para-substitution. The results described in this paper are promising and provide new array of synthetic chemicals that may be utilized as insect growth regulators.

In Vitro Antimicrobial Screening of Benzoylthioureas: Synthesis, Antibacterial Activity toward Streptococcus agalactiae and Molecular Docking Study

“…N ‐(butylcarbamoyl)‐benzamide ( 3 ) was prepared as previously described [15] with some modifications. N ‐ (butylcarbamothioyl)‐benzamide ‐ 1 e was dissolved in 85 % formic acid.…”

“…N ‐( N ‐butylcarbamimidoyl)‐benzamide ( 4 ) was prepared as previously described [15] , with some modifications. Briefly, 40 % aqueous ammonium hydroxide, triethylamine, sodium bismuth and bismuth iodide were added to a solution of N ‐(butylcarbamothioyl)‐benzamide 1 e in acetonitrile under vigorous stirring.…”

“…This substitution was planned to verify the importance of thiourea as a pharmacophore group (Scheme 2B). The synthesis of benzoylurea derivative (3) occurred through sulfur oxidation using hydrogen peroxide as previously reported [15] , while the benzoylguanidine (4) was prepared through desulfurization using bismuth (Bi 3 + ) followed by the addition of ammonium leading to the respective guanidine. [16] The obtention of compounds (2 a-b), (3) and ( 4) was confirmed by melting point and 1H NMR data (Supporting Information), which are according to the literature.…”

“…[16] The obtention of compounds (2 a-b), (3) and ( 4) was confirmed by melting point and 1H NMR data (Supporting Information), which are according to the literature. [15][16][17][18][19] Table 1. Minimal inhibitory concentration (MIC) of benzoylthioureas (1 c, 1 e, 1 f, 1 p) for planktonic cells of microbial species.…”