US EPA

7422701 

Journal Article 

5-Position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives 

Kuninobu, Y; Nishi, M; Kanai, M; , 

2016 

1 

Organic and Biomolecular Chemistry
ISSN: 1477-0520
EISSN: 1477-0539 

ROYAL SOC CHEMISTRY 

CAMBRIDGE 

14 

34 

8092-8100 

English 

27506919 

10.1039/c6ob01325b 

WOS:000382058000015 

http://xlink.rsc.org/?DOI=C6OB01325B
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We developed a copper-catalyzed 5-position-selective C-H trifluoromethylation of 8-aminoquinoline derivatives. The reaction proceeded with high functional group tolerance under mild conditions. In the case of quinolines with an amide, carbamate, urea, or sulfonamide group at the 8-position of quinoline moieties, a radical scavenger experiment indicated that the reaction proceeded via a radical pathway. The protecting group of an 8-amidoquinoline derivative could be removed by hydrolysis. On the other hand, the trifluoromethylation of 8-aminoquinolines was also promoted by other Lewis acids as well as a copper catalyst and proceeded even in the presence of a radical scavenger. These results indicated that the trifluoromethylation of 8-aminoquinolines proceeded via a Friedel-Crafts-type reaction. Interestingly, the copper salt works as either a catalyst for the formation of a CF3 radical or a Lewis acid to promote a Friedel-Crafts-type reaction, depending on the substrate. 

Copper; Sulfur compounds; Urea; 8-aminoquinoline; Copper catalyst; Copper catalyzed; Protecting group; Quinoline moiety; Radical pathway; Radical scavengers; Trifluoromethylation; Catalysts