Linked Life Data

15099099

Source:http://linkedlifedata.com/resource/pubmed/id/15099099

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2004-4-21
pubmed:abstractText
The deprotonation of the alpha-CH3 and alpha-CH2OD groups of hydroxyacetone and the alpha-CH3 groups of acetone in the presence of acetate buffer and zinc chloride in D2O at 25 degrees C was followed by monitoring the incorporation of deuterium by 1H NMR spectroscopy, and the rate laws for catalysis of these reactions by acetate anion and zinc dication were evaluated. Relative to solvent water at a common standard state of 1 M, Zn2+ provides 6.3 and 4.4 kcal/mol stabilizations, respectively, of the transition states for deprotonation of the alpha-CH2OD and alpha-CH3 groups of hydroxyacetone by acetate anion, and a smaller 3.3 kcal/mol stabilization of the transition state for deprotonation of the alpha-CH3 group of acetone. There is only a 1.4 kcal/mol smaller stabilization of the transition state for the acetate-ion-promoted deprotonation of acetone by the Brønsted acid acetic acid than by Zn2+, which shows that, in the absence of a chelate effect, there is no large advantage to the use of a metal dication rather than a Brønsted acid to stabilize the transition state for deprotonation of alpha-carbonyl carbon.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0002-7863
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
126
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5164-73
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
A comparison of the electrophilic reactivities of Zn2+ and acetic acid as catalysts of enolization: imperatives for enzymatic catalysis of proton transfer at carbon.
pubmed:affiliation
Departamento de Química Física, Facultad de Química, Universidad de Santiago, 15706 Santiago de Compostela, Spain.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't