The pyridine-catalysed reaction of methanol with phenyl isocyanate in tetrachloromethane

Abstract

The title reaction is first order in catalyst and each reactant. Several 3- and 4-substituted pyridine catalysts generate a Brönsted plot with slope β of 0.49. This, the steric effect of 2,4,6-trimethylpyridine, the deuterium isotope effect, and the solvent effect are consistent with the general base mechanism of catalysis. The nucleophilic mechanism is considered relatively unlikely. 2-Pyridylmethanol reacts with phenyl isocyanate faster than does 4-pyridylmethanol, indicating intramolecular general base catalysis in the former case.