Purdue sales representatives were instructed to encourage doctors to write prescriptions for larger 12-hour doses instead of more frequent dosing. An August 1996 memo to Purdue sales representatives in Tennessee entitled "$$$$$$$$$$$$$ It’s Bonus Time in the Neighborhood!" reminded the representatives that their commissions would dramatically increase if they were successful in convincing doctors to prescribe larger doses. "Los Angeles Times" journalists argue using interviews from opioid addiction experts that such high doses of OxyContin spaced 12 hours apart create a combination of agony during opiate withdrawal (lower lows) and a schedule of reinforcement that relieves this agony, fostering addiction. Oxycodone's chemical name is derived from codeine. The chemical structures are very similar, differing only in that   It is also similar to hydrocodone, differing only in that it has a hydroxyl group at carbon-14. Oxycodone is marketed as various salts, most commonly as the hydrochloride salt. The free base conversion ratios of different salts are: hydrochloride (0.896), bitartrate (0.667), tartrate (0.750), camphosulfonate (0.576), pectinate (0.588), phenylpriopionate (0.678), sulfate (0.887), phosphate (0.763), and terephthalate (0.792). The hydrochloride salt is the basis of most American oxycodone products whilst bitartrate, tartrate, pectinate, terephthalate and phosphate salts are also available in European Union products. Methyiodide and hydroiodide are mentioned in older European Union publications. In terms of biosynthesis, oxycodone has been found naturally in nectar extracts from the orchid family "Epipactis helleborine"; together along with another opioid: 3-{2-{3-{3-benzyloxypropyl}-3-indol, 7,8-didehydro- 4,5-epoxy-3,6-d-morphinan. Oxycodone and/or its major metabolites may be measured in blood or urine to monitor for clearance, abuse, confirm a diagnosis of poisoning, or assist in a medicolegal death investigation. Many commercial opiate screening tests cross-react appreciably with oxycodone and its metabolites, but chromatographic techniques can easily distinguish oxycodone from other opiates.   and (Jakob) of the University of Frankfurt in Germany published the first synthesis of oxycodone from thebaine in 1916.