773-01-3Relevant articles and documents
N -aminopyridinium salts as precursors for N-centered radicals - Direct amidation of arenes and heteroarenes
Greulich, Tobias W.,Daniliuc, Constantin G.,Studer, Armido
supporting information, p. 254 - 257 (2015/03/05)
Readily prepared N-aminopyridinium salts are valuable precursors for the generation of N-centered radicals. Reduction of these salts by single electron transfer allows for clean generation of amidyl radicals. It is shown that direct radical C-H amination of heteroarenes and arenes can be achieved with N-aminopyridinium salts under mild conditions by using photoredox catalysis.
No-caririeir-added 11C-labelling of benzenoid compounds in ring positions by condensation of nitro-[11C]methane with pyrylium salts
Maeding,Steinbach,Johannsen
, p. 565 - 583 (2007/10/03)
A new synthesis is described for three no-carrier-added nitro-[1-11C] benzenes 3a-c by condensation of nitro-[11C]methane (1) with the appropriate pyrylium salts 2a-c in the presence of a base such as t-BuOK in t-BuOH. For synthesizing 4-nitro-[4-11C]anisole (3a), tetrabutylammonium fluoride was successfully used as an auxiliary base. The best results were obtained in the synthesis of 3a. The conversion of 1 with 4-methoxypyrylium perchlorate (2a) yielded 3a of a radiochemical purity of up to 82% and a mean specific radioactivity of 30 GBq/μmol (0.8 Ci/μmol) within 20 min. Related to 1, the reproducible radiochemical yields of 3a are in the range of 77 ± 5% (decay-corrected). 2,6-Dimethyl-4-methoxy-nitro[1-11C]benzene (3b) was prepared by reaction of 1 with 2,6-dimethyl-4-methoxypyrylium perchlorate (2b) in radiochemical yields of about 37% (decay-corrected) within 10 min. 2-Nitro-[2-11C]mesitylene (3c) was obtained by condensation of 1 with 2,4,6-trimethylpyrylium tetrafluoroborate (2c) in radiochemical yields of about 29% (decay-corrected) within 20 min. 13C/11C Co-labelling experiments were carried out in order to confirm the identity of 3a-c and the position of the label.
SYNTHESE DE N,N-DIALKYL-3,5-DIALKYL-ANILINES A PARTIR DES SELS DE TRIALKYL-2,4,6-PYRYLIUM
Vernaudon, Pascal,Rajoharison, Harivelo G.,Roussel, Chritian
, p. 205 - 211 (2007/10/02)
We have optimized through an experimental design the synthesis of N,N-diethyl-3,5-dimethylaniline from 2,4,6-trimethylpyrylium terafluoroborate (I) and diethylamine in a new reaction medium (acetonitrile/triethylamine).Optimal conditions have been applied with high yields to the synthesis of various 3,5-dimethylanilines derived from I and dimethylamine, morpholine, N-methylpiperazine, piperazine, dihexylamine, piperidine, and pyrrolidine respectively. 2-Alkyl-4,6-dimethylpyrylium tetrafluoroborates react regioselectively with diethylamine to afford N,N-diethyl-3-alkyl-5-methyl anilines under these conditions.
FORMATION OF PYRYLIUM SALTS IN THE ACYLATION OF STERICALLY HINDERED QUINONES
Ukhin, L. Yu.,Dolgopolova, N. A.,Morkovnik, Z. S.,Kuz'mina, L. G.,Struchkov, Yu. T.
, p. 364 - 368 (2007/10/02)
The reaction of 3,5-di-tert-butyl-o-benzoquinone and 2,6-di-tert-butyl-p-benzoquinone with solutions of 70percent HClO4 in acetic and propionic anhydrides and with boron trifluoride etherate in acetic anhydride leads to the formation of pyrylium salts in high yields.
