Partially dissolved 1.28 g (7.0 mmol) 4-dipropylamino-2-butynoic acid in 100 ml THF and chilled to 0° C. under N2. Added 974 μl (8.85 mmol) N-methylmorpholine 768 μl (5.90 mmol) isobutyl chloroformate and stirred for 30 minutes. Added a solution of 1.00 g (2.95 mmol) ) 6-amino-4-[(3-bromophenyl)amino]-3-quinolinecarbonitrile in 8 ml pyridine. At two hours, quenched with ice water and extracted with ethyl acetate. Dried organic layer with magnesium sulfate, reduced solvent to a small volume and loaded onto a column of silica gel. Eluted with ethyl acetate, stripped solvent from desired fractions and dried in vacuo, giving 764 mg of yellow solid: mass spectrum (electrospray m/e): M+H=504, 506.4.
