Synthesis of 11-bromo-9-methyl-6-methylene-3-methylthio-5,6,9,10-tetrahydro-8H-[1,2,4]triazolo[3′,4′;3,4]pyrazino[1,2-c]pyrimidine-8,10-dione from 4-allyl-1-(3-methyl-2,4-dioxo-1,2,3,4-tetrahydro-6-pyrimidinylcarbonyl)thiosemicarbazide
Synthesis of 11-bromo-9-methyl-6-methylene-3-methylthio-5,6,9,10-tetrahydro-8H-[1,2,4]triazolo[3′,4′;3,4]pyrazino[1,2-c]pyrimidine-8,10-dione from 4-allyl-1-(3-methyl-2,4-dioxo-1,2,3,4-tetrahydro-6-pyrimidinylcarbonyl)thiosemicarbazide