Methyl 1-(2,2-dimethoxyethyl)-1,4-dihydro-3-methoxy-4-oxo-5-[[[(2,4,6-trifluorophenyl)methyl]amino]carbonyl]-2-pyridinecarboxylate,Methyl 1-(2,2-dimethoxyethyl)-1,4-dihydro-3-methoxy-4-oxo-5-[[[(2,4,6-trifluorophenyl)methyl]amino]carbonyl]-2-pyridinecarboxylate,Bictegravir Impurity