Synonyms: 4H-Pyrano[4',3':4,5]thieno[2,3-d]pyrimidin-4-one, 6-ethyl-1,2,3,5,6,8-hexahydro-6-methyl-3-(2-methyl-2-propen-1-yl)-2-thioxo-;6-ethyl-6-methyl-3-(2-methyl-2-propenyl)-2-thioxo-1,2,3,5,6,8-hexahydro-4H-pyrano[4',3':4,5]thieno[2,3-d]pyrimidin-4-one;6-Ethyl-6-methyl-3-(2-methylprop-2-en-1-yl)-2-thioxo-1,2,3,5,6,8-hexahydro-4H-pyrano[4',3':4,5]thieno[2,3-d]pyrimidin-4-one