title: Conformationally defined cyclohexyl carnitine analogs.
abstract: Three diastereoisomers of racemic (3-carboxy-2-hydroxy-1-cyclohexyl)trimethylammonium chloride [C10H20NO3+.Cl-; (1S,2S,3S) (2), (1R,2S,3S) (3) and (1S,2R,3S) (4)] were designed as rigid analogs for different low-energy conformational states of carnitine [(1), (3-carboxy-2-hydroxy-1-propyl)trimethylammonium chloride]. Structures (2)-(4) all assume a chair conformation in the solid state, in which the bulky trimethylammonio group occupies the equatorial position. As such, the orientations about C2-C3 in (2), (3) and (4) are all essentially the same as that found for (1) in the solid state (torsion angles for C1-C2-C3-N1 near 180 degrees), while the orientations about C1-C2 in (2)-(4) are such that each diastereoisomer contains a different one of the three possible low-energy staggered conformations predicted for (1) in solution. Comparisons between (1) and (2)-(4) in the solid state revealed that diastereoisomers (2), (3) and (4) provide rigid models for the major low-energy conformations of carnitine.
authors.affiliation: Department of Chemistry, University of Alabama at Birmingham 35294-1240, USA.
authors.forename: W J
authors.initials: WJ
authors.lastname: Brouillette
authors.forename: G M
authors.initials: GM
authors.lastname: Gray
authors.forename: A
authors.initials: A
authors.lastname: Saeed
mesh_terms: D002331:Carnitine / Q000031:analogs & derivatives* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D002331:Carnitine