Survey reactivity of some 1,3- dicarbonyl with pentachloropyridine

Perhalogenated aromatic and heteroaromatic compounds are important starting materials for the synthesis of other heterocyclic [1].Pentachloropyridine reacted with bulky nucleophiles at 2-position of pyridine ring and with small nucleophiles at 4-position of pyridine ring [2]. In this work we investigated the reaction of pentachloropyridinewith anion derived from1,3- dicarbonylcompounds in the presence of potassium carbonate in DMSO as solvent.Our study indicated that the initial substitution occurs atthe 4-position of pyridine ring followed by cyclization at the 3-position of pyridine ring(Figure 1). The structure of compounds was confirmedby 1H-NMR and 13C-NMR spectroscopy data In conclusion, we demonstrated that the reaction of 1,3- dicarbonyl compounds with pentachloropyridine proceeded firstly from carbonsite of nucleophile and subsequence from oxygen site of nucleophile in two products and in 3bcyclisation occurred with oxygen site to 3 position of pyridine ring..