Synthesis, characterization and antimicrobial activities of some quinoxaline-, naphthalene- and xylene-based macrocyclic compounds

Seven novel macrocyclic drug candidates having quinoxaline, naphthalene and xylene subunits were synthesized in order to investigate their antimicrobial suitability in combating drug resistance. The macrocycles and their intermediates were characterize using 1H NMR, 13C NMR, FT-IR and HRMS spectrometry. The intermediates were synthesized by reacting various derivatives of salicylaldehyde with 1,3-bis(aminomethyl)benzene (route I) or 2,4-bis(chloromethyl)-1,3,5-trimethylbenzene (route II), the intermediates were cyclized via [1 + 1] high dilution cyclization reaction into the seven macrocycles in approximately equal yield for both route I and II. Invitro antibacterial and antifungal susceptibility tests were carried out for each of the macrocycles on Staphylococcus aureus, Streptococcus pyogenes, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The macrocycles showed good antimicrobial potency when compare with standard antibiotics (Gentamycin, Tetracyclin, Fluconazole and Amphoteracin B).