Paliperidone-d4 (9-Hydroxy Risperidone-d4, Risperidone EP Impurity C-d4)

3-(2-(4-(6-fluorobenzo[d]isoxazol-3-yl)piperidin-1-yl)ethyl)-9-hydroxy-2-methyl-6,7,8,9-tetrahydro-4H-pyrido[1,2-a]pyrimidin-4-one-D4