Ultrasound Promoted Synthesis and Antimicrobial Evaluation of Novel Seven and Eight-Membered 1,3-Disubstituted Cyclic Amidinium Salts

Series of 1,3-dibenzyl-1H-4,5,6,7-tetrahydro-1,3-diazepinium and 1,4,5,6,7,8-hexahydro-1,3-diazocinium salts derivatives were efficiently synthesized in excellent yields by dehydrogenation of the corresponding N,N'-dibenzyl aminals employing N-bromosuccinimide (NBS) as dehydrogenating agent under ultrasound irradiation. The present methodology has proven to be simple, efficient and environmentally benign. All novel compounds were identified and characterized by 1H and 13C NMR spectra. The synthesized compounds were screened for their antimicrobial activities.