Chemo-, regio- and stereospecific non-catalytic addition of isonicotinic acid to, -acetylenic -hydroxy nitriles

Isonicotinic acid is readily added to α,β-acetylenic γ-hydroxy nitriles through its nitrogen atom under mild non-catalytic conditions in water (50–55°C, 45–50h) to afford chemo-, regio- and stereospecifically 1-[(Z)-2-cyano-1-(1-hydroxy-1-alkylethyl)ethenyl]-pyridinium-4-carboxylates, densely functionalized derivatives of isonicotinic acid (45–90% yields). The structure and zwitterionic character of the adducts are proved by X-ray analysis.