Syntheses, silylation, characterization, and antimicrobial and antifertility activities of organoboron derivatives of some bioactive monofunctional bidentate semicarbazones

Abstract

Some new mononuclear organoboron derivatives of the type PhBL1–5(OH) (1a–1e) were synthesized by the reaction of PhB(OH)2 and LH (LH = OC(NH2)NH:NC(CH3)4C6H4R, where R = H (L1H); CH3(L2H); OCH3(L3H); Cl (L4H); Br (L5H)) in 1:1 molar ratio in refluxing tetrahydrofuran (THF). This was followed by the reactions of PhBL1–5(OH) with NH(SiMe3)2 in 2:1 molar ratio in THF to yield new heterodinuclear derivatives of the type PhBL1–5(OSiMe3) (2a–2e). All these newly synthesized complexes were characterized using elemental analyses and their probable structure was proposed on the basis of infrared, 1H NMR, 13C NMR, 11B NMR and 29Si NMR spectral data and mass spectrometry. Semicarbazone ligands and their corresponding mono‐ and heterodinuclear boron derivatives were screened against pathogenic bacteria (E. coli and P. aeruginosa) and fungi (A. niger and P. peniculosum) to examine their antimicrobial activities. Representative compounds of each series of mono‐ and heterodinuclear boron derivatives and a ligand were screened for their antifertility activity on male adult Wistar rats.