Combined phase transfer catalysis and ultrasound to enhance tandem alkylation of azo dyes

Ultrasound has been found to enhance N-substitution against elimination in the reaction of carbazole-containing bromides with a Disperse Orange 3 derivative under PTC condition. Upon using combined PTC and ultrasound conditions, a series of bifunctional molecules have been prepared to possess charge-transporting agents and nonlinear optical chromophores in 2:1 ratio.