Chemical Name: ethyl 1-(4-methoxyphenyl)-7-oxo-6-(4-(2-oxopiperidin-1-yl)phenyl)-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-c]pyridine-3-carboxylate
Synonym: Mirtazapine EP Impurity E ; (2RS)-4-Methyl-1-(3-methylpyridin-2-yl)-2-phenylpiperazine ; Acyclomirtazapine methyl derivative