STUDIES ON 1,2,4-BENZOTHIADIAZINE 1,1-DIOXIDES-VII AND QUINAZOLINONES-IV - SYNTHESIS OF NOVEL BUILT-IN HYDROXYGUANIDINE TRICYCLES AS POTENTIAL ANTICANCER AGENTS

Two representative built-in hydroxyguanidine tricycles containing 1,2, 4-benzothiadiazine 1,1-dioxides (3) and quinazolinones (4) were prepar ed by reductive cyclization of 2-nitrophenyl-sulfonyl)-2-benzylthio-2- imidazoline (9a), ulfonyl)-2-benzylthio-1,4,5,6-tetrahydropyrimidine ( 9b), 1-(2-nitrobenzoyl)-2-benzylthio-2-imidazolidine (10a) and enzoyl) -2-benzyl-thio-1,4,5,6-tetrahydropyrimidine hydrobromide respectively (10b) with zinc dust in acetic acid under ice-cooling. 0-hydroxy-3H-im idazo[1,2-b][1,2,4]benzothiadiazine 5,5-dioxide (3a) and o-11-hydroxyp yrimido[1,2-b][1,2,4]benzothiadiazine 6,6-dioxide (3b) were found to b e active against solid tumor cell lines such as KB, Colo 205, HeLa, an d Hepa-2.