The Pistoia Alliance Controlled Substance Compliance Service Project: from start to finish.

Pharmaceutical companies and other life science R&D organizations routinely work with controlled substances, and must have adequate controls in place to meet the legislative requirements of the countries in which they operate. Controlled substances include a range of narcotics and psychotropic drugs, which are covered by increasingly complex legislation as legislators attempt to keep up with a rapidly changing environment. This legislation must be interpreted and transformed from legal wording into chemical structures to be used effectively.

(R)-4-(4-Aminophenyl)-2,2,4-trimethylchroman and (S)-4-(4-aminophenyl)-2,2,4-trimethylthiachroman.

The title compounds, C(18)H(21)NO and C(18)H(21)NS, in their enantiomerically pure forms are isostructural with the enantiomerically pure 4-(4-hydroxyphenyl)-2,2,4-trimethylchroman and 4-(2,4-dihydroxyphenyl)-2,2,4-trimethylchroman analogues and form extended linear chains via N-H···O or N-H···S hydrogen bonding along the [100] direction. The absolute configuration for both compounds was determined by anomalous dispersion methods with reference to both the Flack parameter and, for the light-atom compound, Bayesian statistics on Bijvoet differences.