title: Diastereoisomerism of thiol complexes of arsenic acids and pseudoasymmetry of arsenic: a 1H and 13C NMR study.
abstract: Diastereoisomeric complexes of methylphenylarsinic acid and (L)-glutathione could be partially separated by HPLC, but the separated compounds rapidly racemized, presumably by pyramidal inversion at the arsenic atom. Hydrolysis of the diastereoisomeric complexes yielded methylphenylarsinous acid as a pair of enantiomers revealed by a 1H NMR study with an asymmetric lanthanide shift reagent. Methylphenylarsinous acid was also synthesized as an enantiomeric pair, shown by an asymmetric shift reagent experiment, by the hydrolysis of iodomethylphenylarsine. 1H and 13C NMR spectroscopy were used to demonstrate that complexing of phenylarsonic acid with (R,S)-3-mercapto-1,2-propanediol and with (R,S)-1-mercapto-2-propanol yielded, in each case, a pair of enantiomers, PhAs[(R)-ligand)]2, PhAs[(S)-ligand)]2, in which the homomorphic ligands were diastereotopic, and a pair of diastereoisomers, PhAs[(R)-ligand][(S)-ligand], which differed from each other in the configuration about the pseudoasymmetric arsenic atom.
authors.affiliation: Endocrine Disrupter Research Laboratory, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan. edmonds.john.s@nies.go.jp
authors.forename: John S
authors.initials: JS
authors.lastname: Edmonds
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakayama
authors.forename: Takuya
authors.initials: T
authors.lastname: Kondo
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Morita
mesh_terms: D001149:Arsenates / Q000737:chemistry*; D001151:Arsenic / Q000737:chemistry*; D002247:Carbon Isotopes; D002851:Chromatography, High Pressure Liquid; D005978:Glutathione / Q000737:chemistry; D005990:Glycerol / Q000031:analogs & derivatives / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D015394:Molecular Structure; D020005:Propanols / Q000737:chemistry; D011522:Protons; D013237:Stereoisomerism; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry
chemical_list: D001149:Arsenates; D002247:Carbon Isotopes; D008024:Ligands; D020005:Propanols; D011522:Protons; D013438:Sulfhydryl Compounds; D013455:Sulfur; C009465:thioglycerol; D005978:Glutathione; D001151:Arsenic; C025657:arsenic acid; D005990:Glycerol