Hydrogen bond assisted reactivity of Ylidineketonitriles with 1° amines: A chemoselective synthesis of 2-pyridone and 2-aminopyridine derivatives

Ylidineketonitrile 2 with chlorodifluoromethyl (A = Cl) demonstrated a strong solvent dependence reaction with primary amines to form either 1-N-alkylated-3,5-disubstituted-2-pyridones or 2-N-alkylated-3, 5-trisubstituted pyridines. The methodology was tested for its scope with primary amines and synthesized 29 derivatives in good to excellent yield. Ylidineketonitrile 2e preferrentially forms pyridone derivatives in the majority of the solvents screened except trifluoroethanol, where chemoselective formation of 2-aminopyridine derivatives was observed.