Studies on the synthesis and in vitro antitumor activity of the isoquinolone derivatives

3-Arylisoquinolin-1(2H)-ones (2) are possible bioisosteres of the 5-[4'-(pi peridinomethyl)pheny]-2,3-dihydroimidazo[2,1-a]isoquinoline (1) which is in clinical evaluation for the treatment of cancer. Structure-activity relati onship studies of 3-arylisoquinolin-1(2H)-ones (2) led to the synthesis of 3-arylquinolin-2(1H)-ones (3). A number of 3-phenyl substituted quinolin-2( 1H)-ones were synthesized and tested for their in vitro antitumor activity against four different human tumor cell lines and 3-phenyl-N-benzyl-3,4-dih ydroquinolin-2(1H)-one (12) showed the most potent activity.