Isocyanide addition to pyridinium salts. Efficient entry into substituted nicotinonitrile derivatives.
The addition of isocyanides to pyridinium salts is studied. The process takes place efficiently when a carboxamido group is present in the 3 position of the pyridine ring. The outcome of the reaction involves the stabilization of the nitrilium intermediate by the amide, which suffers a mild dehydration, leading regioselectively to beta-cyano-gamma-carbamoyl-1,4-dihydropyridines. In this way, a variety of nicotinamide derivatives were carbamoylated. Extension to quinolinium, isoquinolinium, and N-acylpyridinium salts is also reported. [reaction: see text]
Williams
Nana Aba O
NA
Institute for Research in Biomedicine, Barcelona Science Park, Josep Samitier 1-5, 08028 Barcelona, Spain.
Masdeu
Carme
C
Díaz
José Luis
JL
Lavilla
Rodolfo
R
D000577:Amides / Q000737:chemistry; D003486:Cyanides / Q000737:chemistry*; D009536:Niacinamide / Q000737:chemistry; D009539:Nicotinic Acids / Q000138:chemical synthesis*; D009570:Nitriles / Q000138:chemical synthesis*; D011726:Pyridinium Compounds / Q000138:chemical synthesis*; D011806:Quinolinium Compounds / Q000138:chemical synthesis; D013237:Stereoisomerism
D000577:Amides; D003486:Cyanides; D009539:Nicotinic Acids; D009570:Nitriles; D011726:Pyridinium Compounds; D011806:Quinolinium Compounds; D009536:Niacinamide