290297-34-6Relevant articles and documents
Research and development of an efficient process for the construction of the 2,4,5-substituted pyridines of NK-1 receptor antagonists
Harrington, Peter J.,Johnston, Dave,Moorlag, Henk,Wong, Jim-Wah,Hodges, L. Mark,Harris, Les,McEwen, Gerald K.,Smallwood, Blair
, p. 1157 - 1166 (2012/12/23)
Roche has identified a 2,4,5-trisubstituted pyridine template for a new class of potent NK1 receptor antagonists. Previous strategies for construction of the pyridine core of these NK-1 receptor antagonists involved functionalization of a 2,5-disubstituted pyridine. We now report on construction of the pyridine core from commodity components. Shestopalov reported the synthesis of trans-4′-aryl-5′-cyano-1′,2′,3′, 4′-tetrahydro-6′-hydroxy-2′-oxo-1,3′-bipyridinium inner salts from 1-(2-amino-2-oxo-ethyl)pyridinium chloride, aromatic aldehydes, and ethyl cyanoacetate in the presence of a base. Reaction of these salts with phosphorus oxychloride affords 4-aryl-3-cyano-2,6-dichloropyridines. These are efficiently converted to nicotinamide precursors of the Roche NK-1 receptor antagonists by regioselective displacement of one chlorine by an amine, hydrogenolysis of the remaining chlorine, and nitrile hydrolysis.
