160893-94-7 5H-1,3,4-Thiadiazolo(2,3-b)quinazoline-5-thione, 6,7,8,9-tetrahydro-2-(2-ethoxyphenyl)- 6,7,8,9-Tetrahydro-2-(2-ethoxyphenyl)-5H-1,3,4-thiadiazolo(2,3-b)quinazoline-5-thione