title: Aerial oxidation of the glucocorticoid side-chain under pH control.
abstract: The outcome of aerial oxidation of the glucocortico-steroid side-chain (as exemplified by dexamethasone) has been shown to be subject to strict pH control. At pH 7.4 the glyoxal is the only product; at pH values of 8 and 9.2 the etioacid is formed, and at pH values of 13 or above the epimeric glycolic acids are produced. The glycolic acid epimer that predominates by a factor of 2 and is more stable has been shown by an X-ray crystal structural analysis to be the 20R compound. The presence of arsenite changes the course of the reaction and only the glycolic acids are yielded at pH values of 8 and above.
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: Masatoshi
authors.initials: M
authors.lastname: Morita
authors.forename: Peter
authors.initials: P
authors.lastname: Turner
authors.forename: Brian W
authors.initials: BW
authors.lastname: Skelton
authors.forename: Allan H
authors.initials: AH
authors.lastname: White
mesh_terms: D018053:Arsenites / Q000494:pharmacology; D003907:Dexamethasone / Q000737:chemistry*; D006016:Glycolates / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008279:Magnetic Resonance Imaging; D008956:Models, Chemical; D010084:Oxidation-Reduction; D011965:Receptors, Glucocorticoid / Q000737:chemistry
chemical_list: D018053:Arsenites; D006016:Glycolates; D011965:Receptors, Glucocorticoid; C031149:glycolic acid; D003907:Dexamethasone; C015001:arsenite