8-chloro-11-(4-nitrosopiperazin-1-yl)-5H-dibenzo[b,e][1,4]diazepine; N-Nitroso N-Demethyl Clozapine; Nitroso Compound of Clozapine Impurity C; 3-chloro-6-(4-nitrosopiperazin-1-yl)-11H-benzo[b][1,4]benzodiazepine