I came to think this matter while browsing the DEA's drug scheduling page. There are couple of chemicals called synthetic heroin and then "normal" heroin:
other names: PEPAP, synthetic heroin
other names: MPPP, synthetic heroin
other names: Diacetylmorphine, diamorphine
I thought there were just one type of heroin and that the basic heroin is a synthetic opiate. I'm a bit confused... could someone explain me this?