Novel triazolo[4,3-a]quinazolinone and bis-triazolo[4,3-a : 4,3 '-c]quinazolines: synthesis and antitoxoplasmosis effect

Several quinazoline derivatives containing substituted thiosemicarbazido an d S-methylisothiosemicarbazido groups at the 2-position and at both the 2- and 4-positions have been synthesized. Treatment of the S-methylthiosemicar bazides with morpholine or diethylamine did not give the corresponding guan idines. Instead, they underwent cyclodesulfurization into the condensed rin g systems, [1,2,4]triazolo[4,3-a]quinazolinones and bis-[1,2,4]triazolo[4,3 -a :4',3'-c]quinazolines. Evaluation of the products for antitoxoplasmosis effect by studying the ultrastructure morphology of the organisms using sca nning electron microscopy (SEM) indicated their efficacy in causing structu ral deformity of Toxoplasma gondii. Such a deformity plays an important rol e in obstructing the entry of the organisms into host cells. (C) 1999 Elsev ier Science S.A. All rights reserved.