Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities

The acceptorless dehydrogenative coupling (ADC) reaction is an efficient method for synthesizing quinoline and its derivatives. In this paper, various substituted quinolines were synthesized from 2-aminobenzyl alcohols and aryl/heteroaryl/alkyl secondary alcohols in one pot via a cyclometalated iridium-catalyzed ADC reaction. This method has some advantages, such as easy availability of raw materials, mild reaction conditions, wide range of substrates, and environmental friendliness which conforms to the principles of green chemistry. Furthermore, a gram-scale experiment with low catalyst loading offers the potential to access the aryl/heteroaryl quinolones in suitable amounts. In addition, the antibacterial and antifungal activities of the synthesized quinolines were evaluated in vitro, and the experimental results showed that the antibacterial activities of compounds 3ab, 3ad, and 3ah against Gram-positive bacteria and compound 3ck against C. albicans were better than the reference drug norfloxacin.