title: Intramolecular hydrogen bonding (proton transfer) of 1-phenyl-1,3-butanedione.
abstract: Through the (1)H and (13)C NMR measurements for the symmetrical beta-diketones such as 2,4-pentanedione and 1,3-diphenyl-1,3-propanedione and unsymmetrical one such as 1-phenyl-1,3-butanedione at various concentrations and temperatures, we confirmed that 1-phenyl-1,3-butanedione in CDCl(3) exists as monomers in its relatively low concentration. In addition, the 1-phenyl-1,3-butanedione in CDCl(3) exists not as a keto-form but as two kinds of cis-enol forms. The proton transfer between the two kinds of cis-enols for 1-phenyl-1,3-butanedione was discussed thermodynamically; it is concluded that the OH proton of enol of 1-phenyl-1,3-butanedione is considerably located near the oxygen atom attached to the carbon atom linking to a phenyl group.
authors.affiliation: School of Science, Kitasato University, Kitasato, Sagamihara, Japan. matsu@sci.kitasato-u.ac.jp
authors.forename: Hideyo
authors.initials: H
authors.lastname: Matsuzawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakagaki
authors.forename: Makio
authors.initials: M
authors.lastname: Iwahashi
mesh_terms: D002074:Butanones / Q000032:analysis / Q000737:chemistry*; D006860:Hydrogen Bonding; D011522:Protons
chemical_list: D002074:Butanones; D011522:Protons; C035851:benzoylacetone