A convenient synthesis of 2‐Arylidene‐5 H ‐thiazolo[2,3‐ b ]quinazo‐line‐3,5[2 H ]‐diones and their benzoquinazoline derivatives

Various 5 H ‐thiazolo[2,3‐ b ]quinazoline‐3,5[2 H ]‐diones (7a,b), 2‐arylidene‐5 H ‐thiazolo[2,3– b ]quin‐azoline‐3,5[2 H ]‐diones ( 9a‐o ) and 2‐arylidene‐5 H ‐thiazolo[2,3‐ b ]benzoquinazoline‐3,5[2 H ]‐diones ( 12a,b ) have been synthesized via simple and efficient methods.