Selectfluor-promoted regioselective chlorination/bromination of 2-aminopyridines and 2-aminodiazines using LiCl/LiBr
Using LiCl as a chlorine source, the chlorination of 2-aminopyridines or 2-aminodiazines in the presence of Selectfluor and DMF is established under mild conditions. This method gives chlorinated pyridines or diazines in good to high yields with high regioselectivities. Also, this method is extended to the bromination of 2-aminopyridines or 2-aminodiazines by using LiBr. The regioselectivity of the chlorination reaction is strongly dependent upon the substituent pattern in either the 2-aminopyridines or 2-aminodiazines. The synthesis of Buparlisib from chlorinated pyridines was explored. A study of the mechanism revealed that this chlorination occurs via either a pyridine or diazine radical process.
Hu, Jiao,Zhou, Gang,Tian, Yawei,Zhao, Xiaoming
supporting information
p. 6342 - 6345
(2019/07/10)
N-heterocyclyl sulphonamide derivatives and their use as endothelin antagonists
The invention concerns pharmaceutically useful N-heterocyclyl sulphonamide derivatives, their pharmaceutically acceptable salts, processes for their manufacture, their use for antagonising one or more actions of endothelin in a human or other warm-blooded animal, their use in methods of treatment of diseases or medical conditions in which elevated or abnormal levels of endothelin play a significant causative role.
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(2008/06/13)
Studies on Pyrazines. 6. A Facile Separation Method for a Mixture of the Isomeric 2-Amino-3,5, and 6-methylpyrazines
This paper describes a facile separation method for a mixture of the isomeric aminomethylpyrazines by two-stage processes.Thus the mixture of aminomethylpyrazines was converted into that of the aminobromomethylpyrazines, which could be separated by chromatography on silica gel.Each of the bromopyrazines was hydrogenated to regenerate the original aminopyrazine as a pure form.
Sato, Nobuhiro
p. 143 - 147
(2007/10/02)
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