Viktoria Nasyrova, a 47-year-old Brooklyn woman, was sentenced to 21 years in prison on Wednesday for attempting to kill her lookalike friend with a poisoned cheesecake. The chemical used was phenazepam, a benzodiazepine developed by the Soviet Union, and the jury deliberated for two days before convicting Nasyrova of attempted murder and other counts. The Queens district attorney’s office said the case was a reminder that justice will be served no matter the circumstances.