title: Synthesis and reactivity of (benzoxazol-2-ylmethyl)phosphonic acid.
abstract: An efficient three step synthesis of (benzoxazol-2-ylmethyl)phosphonic acid (6-H(2)) is described along with IR, mass spectrometry (MS), and (1)H, (13)C, and (31)P NMR spectroscopic characterization data, and a single crystal X-ray diffraction structure determination. 6-H(2) is unstable in acidic aqueous solutions (pH < 4) undergoing ring-opening to give [(2-hydroxyphenylcarbamoyl)methyl] phosphonic acid (7-H(2)) that is characterized by IR, MS, and NMR methods. The protonation constants (pK(a)) for 7-H(2) have been measured, and crystal structure determinations for (NH(4))(7-H) and K(7-H)·DMF are described. Reactions of NaOH and KOH with 6-H(2) in MeOH/H(2)O solutions led to isolation and crystal structure determinations of the salts [Na(6-H)·H(2)O](2), K(6-H), Na(3)(6)(6-H)·H(2)O, and [K(2)(6)](2)·3H(2)O. The complexation reactions of 7-H(2) with La(III), Nd(III), and Gd(III), as a function of pH, were also examined by titrametric methods, and a model for the 1:1 anion binding with Ln(III) cations is proposed.
authors.affiliation: Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, USA.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Pailloux
authors.forename: Cornel Edicome
authors.initials: CE
authors.lastname: Shirima
authors.forename: Karen Ann
authors.initials: KA
authors.lastname: Smith
authors.forename: Eileen N
authors.initials: EN
authors.lastname: Duesler
authors.forename: Robert T
authors.initials: RT
authors.lastname: Paine
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Williams
authors.forename: Robert D
authors.initials: RD
authors.lastname: Hancock
mesh_terms: D000042:Absorption; D001583:Benzoxazoles / Q000138:chemical synthesis* / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000737:chemistry; D063065:Organophosphonates / Q000138:chemical synthesis* / Q000737:chemistry*; D012996:Solutions
chemical_list: C555445:(benzoxazol-2-ylmethyl)phosphonic acid; D001583:Benzoxazoles; D008670:Metals; D063065:Organophosphonates; D012996:Solutions