The synthesis of a series of 4-(7,7-dimethyl-4-[4-{N-aroyl/(het)aroyl/ benzyl}1-piperazinyl]-5,6,7,8- tetrahydroquinazolin-2-yl)morpholine derivatives has been described. The antiviral activity of these compounds against avian paramyxovirus (APMV-1), which is a Newcastle disease virus has also been screened.