Highly Regioselective Halogenation of Pyridine <i>N</i>-Oxide: Practical Access to 2-Halo-Substituted Pyridines
作者:Ying Chen、Jinkun Huang、Tsang-Lin Hwang、Maosheng J. Chen、Jason S. Tedrow、Robert P. Farrell、Matthew M. Bio、Sheng Cui
DOI:10.1021/acs.orglett.5b01057
日期:2015.6.19
A highly efficient and regioselective halogenation reaction of unsymmetrical pyridine N-oxide under mild conditions is described. The methodology provides a practical access to various 2-halo-substituted pyridines, which are pharmaceutically important intermediates.
Application of 1,1-ADEQUATE, HMBC, and Density Functional Theory To Determine Regioselectivity in the Halogenation of Pyridine <i>N</i>-Oxides
作者:Tsang-Lin Hwang、Michael D. Bartberger、Ying Chen
DOI:10.1021/acs.orglett.6b00370
日期:2016.5.6
two-bond proton to carbon correlations to unequivocally distinguish the major and minor regioisomers of ortho-halogenated pyridines and to aid in assignment of the corresponding proton and carbon chemical shifts. M06-2X/6-31+G(d,p) free energies of the regioisomeric intermediates arising from deprotonation correctly predict the experimentally observed preference and thus can be used to tune the substituent
Mild, General, and Regioselective Synthesis of 2-Aminopyridines from Pyridine N-Oxides via N-(2-Pyridyl)pyridinium Salts
作者:Hui Xiong、Adam T. Hoye
DOI:10.1055/s-0040-1719865
日期:2022.3
2-aminopyridines frompyridine N-oxides via their corresponding N-(2-pyridyl)pyridinium salts has been demonstrated and investigated. The reaction sequence features a highly regioselective conversion of the N-oxide into its pyridinium salt followed by hydrolytic decomposition of the pyridinium moiety to furnish the 2-aminopyridine product. The method is compatible with a wide range of functional groups, is
An Efficient, Regioselective Amination of 3,5-Disubstituted Pyridine <i>N</i>-Oxides Using Saccharin as an Ammonium Surrogate
作者:Robert P. Farrell、Maria Victoria Silva Elipe、Michael D. Bartberger、Jason S. Tedrow、Filisaty Vounatsos
DOI:10.1021/ol303218p
日期:2013.1.4
A process for the regioselective amination of unsymmetrical 3,5-substituted pyridine N-oxides has been developed utilizing cheap, readily available saccharin as an ammonium surrogate. High conversions of the corresponding saccharin adducts have been achieved under mild reaction conditions. In situ deprotection under acidic conditions allows for a one-pot process to substituted aminopyridines. High regioselectivities were obtained from a variety of 3,5-disubstituted pyridine N-oxides.