New 2,8-Bis(Trifluoromethyl)Quinoline-4-Carboxamides As Potential Antimycobacterial Agents

Bacterial infections are the second leading cause of mortality worldwide and represent a major global health challenge. In 2023, approximately 1.25 million deaths were linked to tuberculosis, making it one of the deadliest infectious diseases in the world. In recent years, non-tuberculous mycobacteria (NTM) have also become a public health issue and are closely monitored by researchers. Currently, their incidence exceeds that of tuberculosis in North America and Europe, with 1.0 to 1.8 cases per 100,000 people. NTM are opportunistic bacteria and commonly found in natural or urban water sources. Some species are known as pulmonary pathogens and mainly infect people with compromised immune systems or pre-existing lung diseases such as cystic fibrosis, bronchiectasis, or chronic obstructive pulmonary disease. NTM are classified into two main groups : slow-growing species such as MAC complex (with M. avium, M. intracellulare, and M. chimaera mainly), M. xenopi and M. kansasii, and rapid-growing species such as M. abscessus complex (smooth and rough) and M. fortuitum. Current NTM infection treatments involve a long treatment (18 to 24 months) and rely on a combination of three antibiotics, generally including a macrolide. However, the effectiveness of these treatments remains limited, with a moderate cure rate, some side effects, and an increasing resistance to macrolides. Some developed or commercial antimicrobial agents, containing a quinoline ring, have shown potent antimycobacterial activity against NTM, such as bedaquiline (BQ), mefloquine (MQ), and Labio-17. Based on MQ’s pharmacophore, the main objective of this work was to develop new 2,8-bis(trifluoromethyl)quinoline-4-carboxamides as new antimycobacterial agents. Here, we present the design, synthesis, and first biological results of new MQ-based compounds.