3-(2-Chloroethyl)-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one; 3-(2-Chloroethyl)-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one; 9-Hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one; 3-(2-Chloroethyl)-9-hydroxy-2-methyl-4H-pyrido[1,2-a]pyrimidine-4-one; 3-(2-Chloroethyl)-2-methyl-9-hydroxy-4H-pyrido[1,2-a]pyrimidine-4-one;,Paliperidone Impurity