PREPARATION OF 2-CHLOROPYRIDINE

Abstract

Regiospecific chlorination of pyridine-N-oxide to give 2-chloropyridine was achieved in 90% yield with 99.2% selectivity by treatment with phosphorus oxychloride in the presence of a stoichiometric amount of triethylamine. Other chlorinating agents such as sulfuryl chloride, p-toluenesulfonyl chloride, trichloroacetyl chloride, benzenesulfonyl chloride and methanesulfonyl chloride produced 2-chloropyridine also under these conditions, albeit in moderate yield.