title: (R)-4-(4-Aminophenyl)-2,2,4-trimethylchroman and (S)-4-(4-aminophenyl)-2,2,4-trimethylthiachroman.
abstract: 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.
authors.affiliation: Pharmorphix Solid State Services, A Sigma-Aldrich Company, 250 Cambridge Science Park, Milton Road, Cambridge CB4 0WE, England. chris.frampton@sial.com
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Frampton
authors.forename: David D
authors.initials: DD
authors.lastname: MacNicol
authors.forename: Derek R
authors.initials: DR
authors.lastname: Wilson
mesh_terms: D002839:Chromans / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: C559653:(R)-4-(4-aminophenyl)-2,2,4-trimethylchroman; D002839:Chromans