If morphine is treated with the chemical acetic anhydride, it can be converted into another powerful analgesic called

Heroin

Heroin has the chemical formula  and has the chemical name (IUPAC), (5α,6α)-7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol diacetate. 

Heroin is also known as diamorphine. It can be produced from morphine reacting with a powerful acetic anhydride, or it can be obtained naturally from seed pods of certain opium poppy plants. Heroin is commonly used as a recreational drug as it induces euphoric effects. Medically, it can be used to relieve pain or used in an opioid replacement therapy.