4-(3-Methylphenyl)-2H-pyrido[4,3-e]-1,2,4-thiadiazin-3(4H)-one 1,1-dioxide; 4-m-Tolyl-2H-pyrido[4,3-e][1,2,4]thiadiazin-3(4H)-one 1,1-dioxide; 4-(3-tolyl)-2H-pyrido[4,3-e][1,2,4]thiadiazin-3(4H)-one 1,1-dioxide