Linked Life Data

19572583

Source:http://linkedlifedata.com/resource/pubmed/id/19572583

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2009-9-3
pubmed:abstractText
A series of arylsulfonate nucleophile assisting leaving groups (NALGs) were prepared in which the metal chelating unit is attached to the aryl ring via an ether linker. These NALGs exhibited significant rate enhancements in halogenation reactions using metal halides. Studies with a NALG containing a macrocyclic ether unit suggest that rate enhancements of these nucleophilic halogenation reactions are facilitated by stabilization of charge in the transition state rather than through strong precomplexation with metal cation. In several cases, a primary substrate containing one of the new leaving groups rivaled or surpassed the reactivity of triflates when exposed to nucleophile but was otherwise highly stable and isolable. These and previously disclosed chelating leaving groups were used in (18)F-fluorination reactions using no-carrier-added [18F]fluoride ion (t(1/2) = 109.7 min, beta+ = 97%) in CH3CN. Under microwave irradiation and without the assistance of a cryptand, such as K2.2.2, primary substrates with select NALGs led to a substantial improvement (2-3-fold) in radiofluorination yields over traditional leaving groups.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-10419855, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-11818465, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-12032292, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-12197720, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-14980627, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-15161306, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-15713075, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-16277337, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-16599631, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-17165796, http://linkedlifedata.com/resource/pubmed/commentcorrection/19572583-1849557
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1520-6904
pubmed:author
pubmed:issnType
Electronic
pubmed:day
7
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5290-6
pubmed:dateRevised
2010-9-27
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Nucleophile assisting leaving groups: a strategy for aliphatic 18F-fluorination.
pubmed:affiliation
Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892-1003, USA. shuiyu.lu@mail.nih.gov
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural