principal component analysis (PCA)
hydrogen bonding ability
solvation of carbamate phases
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Chromatographic resolution of 12 derivatives in the 4a-methyl-2,3,4,4a-tetrahydro-1H-fluorene and 4a-methyl-1,2,3,4,4a,9a-hexahydrofluoren-9-one series differing by the framework around position 9 and substitution in position 6, are reported on Chiralcel OD, Chiralpak AD, and Chiralpak AS under two elution conditions and according to the two classes of enantiomers. Results from principal component analysis (PCA) as well as hierarchical clustering show a clustering of the actual compounds depending on properties around position 9, the effect of the substituent in position 6 (methyl, chloro or fluoro) not being strong enough to intermesh the data. Carbamate phases show very different properties when they are used in the separation of a series of ketones C and α-chloroketones D, which differ in basicity and the steric requirement around the carbonyl. Analysis of the effect of 2-PrOH content in hexane on the retention is consistent with a large difference in solvation of the carbamate moiety by 2-PrOH, in the order Chiralcel OD 〉 Chiralpak AD 〉 Chiralpak AS. 4a-Methyl-2,3,4,4a-tetrahydro-1H-fluorene derivatives, which lack hydrogen bonding sites, are not discriminated on these CSPs and show identical k′ responses to 2-PrOH content changes on the three CSPs. Chirality 10:770-777, 1998. © 1998 Wiley-Liss, Inc.
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