Ethyl 1,6-dihydro-1,1-dioxo-5-methyl-1,2,6-thiadiazine-3-carboxylateEthyl 5-methyl-1,1-dioxo-1,6-dihydro-1lambda~6~,2,6-thiadiazine-3-carboxylateEthyl 5-methyl-1,1-dioxo-1,6-dihydro-1lambda~6~ 2,6-thiadiazine-3-carboxylateethyl 5-methyl-1,1-dioxo-1,6-dihydro-1lambda~6~,2,6-thiadiazine-3-carboxylate