N-Substituted 3-amino-4-halopyridines are valuable synthetic intermediates, as they readily provide access to imidazopyridines and similar heterocyclic systems. The direct synthesis of N-substituted 3-amino-4-halopyridines is problematic, as reductive aminations and base-promoted alkylations are difficult in these systems. A high yielding deprotection/alkylation protocol mediated by trifluoroacetic acid and trimethylsilyl trifluoromethanesulfonate is described, providing access to a wide scope of N-substituted 3-amino-4-halopyridines. This protocol furnishes many reaction products in high purity without chromatography. Similar reductive amination conditions were also established for deactivated anilines.
N-Substituted 3-amino-4-halopyridines are valuable synthetic intermediates, as they readily provide access to n class="Chemical">imidazopyridines and similar heterocyclic systems. The direct synthesis of N-substituted 3-amino-4-halopyridines is problematic, as reductive aminations and base-promoted alkylations are difficult in these systems. A high yielding deprotection/alkylation protocol mediated by trifluoroacetic acid and trimethylsilyl trifluoromethanesulfonate is described, providing access to a wide scope of N-substituted 3-amino-4-halopyridines. This protocol furnishes many reaction products in high purity without chromatography. Similar reductive amination conditions were also established for deactivated anilines.
Authors: Ahmed F. Abdel-Magid; Kenneth G. Carson; Bruce D. Harris; Cynthia A. Maryanoff; Rekha D. Shah Journal: J Org Chem Date: 1996-05-31 Impact factor: 4.354
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Authors: Curt A Dvorak; Richard Apodaca; Ann J Barbier; Craig W Berridge; Sandy J Wilson; Jamin D Boggs; Wei Xiao; Timothy W Lovenberg; Nicholas I Carruthers Journal: J Med Chem Date: 2005-03-24 Impact factor: 7.446