The selective C-N cross-coupling of 2-fluoro-4-iodopyridine with aromatic amines is reported. In contrast to conventional substitutions where C-N bond formation takes place at the 2-position (e.g., 2,4-dichloropyridine), the Buchwald-Hartwig cross-coupling was found to be complementary and exclusive for the 4-position. Reactions were carried out under microwave irradiation typically within 30 minutes. These conditions also allowed a decrease in the amount of base required to 3.5 equivalents compared to 20 equivalents in established protocols. Additionally, use of potassium carbonate as a mild base was sufficient, and good yields of the coupling products were obtained in all cases with the simple system Pd(OAc)2/BINAP.
The present invention relates to compounds suitable for modulating huntingtin protein processing and useful for treating or preventing huntingtin-related disorders. The invention provides pharmaceutical compositions comprising said compounds and methods of syntheses thereof.
Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries
作者:Rebecca J. Burton、Mandy L. Crowther、Neal J. Fazakerley、Shaun M. Fillery、Barry M. Hayter、Jason G. Kettle、Caroline A. McMillan、Paula Perkins、Peter Robins、Peter M. Smith、Emma J. Williams、Gail L. Wrigley
DOI:10.1016/j.tetlet.2013.10.035
日期:2013.12
The highly regioselective Buchwald-Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald-Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. (C) 2013 Elsevier Ltd. All rights reserved.