Darstellung von 6‐(Ethoxymethylenimino)‐1,2,4‐triazolo[3′,4′:5,1] [1,2,4]triazolo[4,3‐ a ]chinazolin‐7(6 H )‐one

As a progressive continuation of our study in the condensed quinazolinone series 1, 2) , we recently described the synthesis and antihypertensive activity of some 4‐amino[1,2,4]triazolo[4,3‐a]quinazolin‐5(4H)‐one derivatives ( 1a‐c , R=H, OH, SH). Now, we wish to report the conversion of one of these derivatives, namely 4‐amino‐1‐mercapto‐[1,2,4]‐triazolo[4,3‐a]quinazolin‐5(4H)‐one (1c) into a more complicate condensed quinazolinone system.