A buddy of mine used to run a research chem. site that sold various chemicals for "experimentation". The business as a whole went on for roughly 4-5 years with only minor difficulties until the DEA finally found a way to shut everyone down though it was legal at the time.
It was an EXTREMELY profitable venture, however if you try it now you will be thrown in jail.
DEA Article -
http://www.dea.gov/pubs/pressrel/pr072204.html