Dolutegravir isopropyl analouge

: Dolutegravir -isopropylether impurity; (4R)-N-(2,4-difluorobenzyl)-7-isopropoxy-4-methyl-6,8-dioxo-3,4,6,8,12,12a-hexahydro-2H-[1,3]oxazino[3,2-a]pyrido[1,2-d]pyrazine-9 carboxamide; (4R,12aS)-N-(2,4-difluorobenzyl)-7-isopropoxy-4-methyl-6,8-dioxo-3,4,6,8,12,12a-hexahydro-2H-[1,3]oxazino[3,2-a]pyrido[1,2-d]pyrazine-9-carboxamide