synthesizer prototype. All measured radiochemicalyields exceeded 37%, and the 11CO trapping efficiency was generally above 90%, except for the Suzukicoupling where the trapping efficiency was 80%. This high‐pressure synthesizer using [11C]carbon monoxide as the labeling precursor is easy to operate allowing for 11C‐carbonylation reactions to be performed in a high yield and in a routinely fashion.
Aryl triflates, methyl- or arylboronic acids, and a low concentration of [11C]carbon monoxide were employed on small scale in the syntheses of fifteen 11C-labelled ketones using palladium-mediated ...
palladium-catalyzed [11C]carbonylation of aryl halides and triflates was achieved at atmosphericpressure by employing xantphos as the supportingligand. Aryl halides were converted into their corresponding [11C]amides in good to excellent yields. The conditions were also successfully employed in the radiolabeling of an [11C]ester, a [11C]carboxylic acid, an [11C]aldehyde, and a [11C]ketone.
[11C]Carbon monoxide in the palladium-mediated synthesis of 11C-labelled ketones
作者:Pelle Lidström、Tor Kihlberg、Bengt Långström
DOI:10.1039/a703062b
日期:——
[11C]Carbon monoxide has been used in the
palladium-mediated synthesis of
[carbonyl-11C]ketones. Methyl iodide, vinylic and
arylic halides and trifluoromethanesulfonates (triflates) have been
coupled with tin reagents with insertion of [11C]carbon
monoxide at very low concentrations (10–100 nmol
[11C]CO in a total volume of 10 ml). The labelled products
are obtained in 36–62% isolated decay-corrected radiochemical
yields within 30 min of the end of radionuclide production. In order to
use [11C]carbon monoxide efficiently, a gas handling system
has been developed which allows the radioactive gas to recirculate
through the reaction media. The reactions are performed using a one pot
procedure. The best results are achieved with mixed tin reagents
containing an unsaturated transferable substituent and
Pd(AsPh3)4. In a typical experiment starting from
25 GBq of [11C]carbon dioxide, 4.2 GBq (47%) of
[carbonyl-11C]acetophenone 1 is obtained 30 min
after the end of radionuclide production. The specific radioactivity of
1 is 91 GBq µmol-1.
[carbonyl-13C]Benzophenone 6 has been synthesised
using the same approach to verify the position of the label.
Palladium(II)-mediated 11C-carbonylative coupling of diaryliodonium salts with organostannanes—a new, mild and rapid synthesis of aryl [11C]ketones
作者:Mohammed H. Al-Qahtani、Victor W. Pike
DOI:10.1039/a907803g
日期:——
[11C]carbonylative coupling of diaryliodoniumsalts with aryltributylstannanes for 1 min in DME–water (4∶1 v/v) at RT gives a new mild and rapid route to aryl [11C]ketones. Substituted aryltributylstannanes couple with diphenyliodonium bromide to give substituted [11C]benzophenones in generally very high radiochemical yield (>98%, decay-corrected), while diphenyliodonium tosylates, bearing one or two