Linked Life Data

20361793

Source:http://linkedlifedata.com/resource/pubmed/id/20361793

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2010-5-14
pubmed:abstractText
A microreactor was applied to produce ortho-substituted [(18)F]fluoroarenes from the reactions of cyclotron-produced [(18)F]fluoride ion (t(1/2) = 109.7 min) with diaryliodonium salts. The microreactor provided a very convenient means for running sequential reactions rapidly with small amounts of reagents under well-controlled conditions, thereby allowing reaction kinetics to be followed and Arrhenius activation energies (E(a)) to be measured. Prepared symmetrical iodonium chlorides (Ar(2)I(+)Cl(-)) rapidly (<4 min) gave moderate (Ar = 2-MeOC(6)H(4), 51%) to high (Ar = Ph or 2-MeC(6)H(4), 85%) decay-corrected radiochemical yields (RCYs) of a single radioactive product (Ar(18)F). Reaction velocity with respect to Ar group was 2-MeOC(6)H(4) < Ph < 2-MeC(6)H(4). Activation energies were in the range 18-28 kcal/mol. Prepared unsymmetrical salts (e.g., 2-RC(6)H(4)I(+)2'-R'C(6)H(4)X(-); X = Cl or OTs) also rapidly gave two products (2-RC(6)H(4)(18)F and 2-R'C(6)H(4)(18)F) in generally high total RCYs (79-93%). Selectivity for product [(18)F]fluoroarene was controlled by the nature of the ortho substituents. The power of ortho substituents to impart an ortho-effect was in the following order:, 2,6-di-Me > 2,4,6-tri-Me > Br > Me > Et approximately (i)Pr >> H > OMe. For (2-methyphenyl)(phenyl)iodonium chloride, the time-course of reaction product selectivity was constant and consistent with the operation of the Curtin-Hammett principle. These results will aid in the design of diaryliodonium salt precursors to (18)F-labeled tracers for molecular imaging.
pubmed:grant
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-6904
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
75
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3332-8
pubmed:dateRevised
2011-7-28
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Fast and high-yield microreactor syntheses of ortho-substituted [(18)F]fluoroarenes from reactions of [(18)F]fluoride ion with diaryliodonium salts.
pubmed:affiliation
PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, Rm. B3 C346A, Building 10, 10 Center Drive, Bethesda, Maryland 20892-1003, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Intramural