Bisbenzamidine and Bisbenzguanidine Ureas Act as Antibacterial Agents against Pseudomonas aeruginosa

Abstract

Due to the global rise in the number of antibiotic resistant bacterial infections over the past 20 years, there is a dire need for the development of small molecule antibiotics capable of overcoming resistance mechanisms in pathogenic bacteria. Antibiotic development against Gram-negative pathogens, such as Pseudomonas aeruginosa, is especially challenging due to their additional outer membrane which reduces antibiotic entry. Recently, it has been shown that a broad range of nitrogen functionality, including guanidines, amidines, primary amines, imidazolines, and imidazoles, promote antibiotic and adjuvant activity in Gram-negative bacteria, but few of these have been targeted towards Pseudomonas aeruginosa specifically despite this pathogen being deemed a critical threat by the United States Centers for Disease Control and Prevention. Herein, we examined a small series of known and unknown nitrogenous dimers, with guanidine, amidine, dimethyl amine, and pyridine functionality, for antibacterial activity against multidrug resistant Pseudomonas aeruginosa. We found that two, with bisbenzguanidine and bisbenzamidine functionality, are potent against clinical isolates of multidrug resistant and biofilm forming Pseudomonas aeruginosa.

Keywords: amines; antibiotics; dimerization; pseudomonas aeruginosa.

Scheme 1.

Synthesis of bisbenzguanidine ureas 10, 11, and 12.

Scheme 2.

Synthesis of bisbenzamidine urea 16.

Scheme 3.

Synthesis of bisdimethylamino urea 18 and bispyridine urea 20.

Scheme 4.

Synthesis of bisbenzguanidine 23.

Scheme 5.

Synthesis of fluorinated bisbenzguanidine urea 27.