Deprotonation of 1-(carbethoxyalkyl)pyridinium halides with strong N-bases

The rate constants were measured for deprotonation of 1-(carbethoxymethyl)p yridinium chloride and 1-(2-carbethoxyethyl)pyridinium bromide with strong bases (DBU, MTBD, TBD and P2-Et) in acetonitrile. The UV spectra and semiem pirical calculations are consistent with an ylide structure of the deproton ated species. The ylides obtained slowly decompose, and the reaction produc ts were identified by H-1 NMR spectroscopy; 1-(carbethoxymethyl)pyridinium chloride gives N-methylpyridinium cation and ethanol and 1-(2-carbethoxyeth yl)pyridinium bromide converts to pyridine and ethyl acrylate. Copyright (C ) 1999 John Wiley & Sons, Ltd.