Successive substitution of halogen atoms in 4, 6-dihaloquinolines in palladium-catalyzed reactions with amines and arylboronic acids

Acid-Promoted Cascade Reaction of N-(4-Chloroquinolin-3-yl)carbamates with Amines: One-Pot Assembly of Imidazo[4,5-c]quinolin-2-one

An acid-promoted cascade reaction of 4-chloroquinolin-3-yl carbamates with amines is described. This method achieves the formation of two new C-N bonds through an intermolecular amination/intramolecular cyclization reaction sequence. In combination with subsequent Suzuki coupling, this three-component telescopic procedure provides rapid access to various bioactive imidazo[4,5-c]quinolin-2-one derivatives.

Studies of one-pot double couplings on dibromoquinolines

In a series of studies, the regioselectivity of Suzuki couplings of dibromoquinolines has been investigated. In general, it is much harder to achieve high levels of regioselectivity in these systems compared to many of the other dibromoheteroaromatics that have been studied. Useful levels of selectivity could be achieved for both a 5,7-dibromoquinoline as well as 3,4-dibromoquinoline. Double Suzuki couplings could also be achieved on these two compounds.

Regioselective double Suzuki couplings of 4,5-dibromothiophene-2-carboxaldehyde

Conditions have been identified that enable the one-pot double Suzuki coupling of 4,5-dibromothiophene-2-carboxaldehyde to proceed in good yield. The key to success in these reactions is the use of minimal amounts of water to avoid significant amounts of dehalogenation during the first coupling.