Further studies on ethenyl and ethynyl-4-phenylamino-3-quinolinecarbonitriles: identification of a subnanomolar Src kinase inhibitor

New ethynyl and ethenyl-4-phenylamino-3-quinolinecarbonitrile derivatives were synthesized and tested for Src inhibition. The N-oxide derivative 20b is the first 3-quinolinecarbonitrile to show subnanomolar inhibitory activity in a Src enzyme assay.