The Synthesis and Reactions of 1‐(2‐Propynyl)pyidinium Salts

Abstract The synthesis of 1‐(2‐propynyl)pyridinium salts 3 described. Compounds 3 react with a second pyridine molecule, in the presence of the corresponding hydrochloride, to form products of type 4 , Certain bases cause the 1‐(2‐propynyl)pyridinium salts 3 to rearrange into 1‐propadienylpyridinium salts. 5 . Diethylamine converts compounds 3 into 1‐acetonylpyridinium salts 8 . Moreover, treatment of 3 or 5 with sodium methoxide gives enol ether sof type 9, which can be hydrolyzed to teh ketones 8 . Addition of bromine to some of teh unsaturated compounds is also reported.