Substituted Quinazolines, Part 2. Synthesis and In‐Vitro Anticancer Evaluation of New 2‐Substituted Mercapto‐3 H ‐quinazoline Analogs

A new series of 2‐substituted mercapto‐3 H ‐quinozolines bearing 6‐iodo and 2‐heteroarylthio functions was synthesized and screened for their in vitro antitumor activity. Eighteen compounds were identified as active anticancer agents. N ′‐[(3‐Benzyl‐4‐oxo‐6‐iodo‐3 H ‐quinazoline‐2‐yl)thioacetyl]‐ N 3 ‐ethylthiosemicarbazide ( 10 ), N ‐benzoyl‐ N ′‐[2‐(3‐benzyl‐4‐oxo‐6‐iodo‐3 H ‐quinozolin‐2‐yl)thioacetyl]hydrazine ( 12 ), and 2‐[(3, 6‐dioxo‐pyridazin‐4‐yl)thio]‐3‐benzyl‐4‐oxo‐6‐iodo‐3 H ‐quinazoline ( 20 ) proved to be the most active members in this study. They showed MG‐MID, GI 50 values of 12.8, 11.3, and 13.8 μM, respectively. The detailed synthesis and biological screening data are reported.