Some 1,3-dipolar cycloaddition reactions of perfluoro-(2-azido-4-isopropylpyridine) and 2-azido-3,5,6-trifluoro-4-methoxypyridine

Abstract

Abstract In continuation with studies on perfluorinated aryl [1] and hetaryl [2] azides some 1,3-dipolar cycloaddition reactions of perfluoro-(2-azido-4-isopropylpyridine) are summarized in Scheme 1. The azide reacts with styrene under forcing thermal conditions to give a mixture of perfluoro-(2-amino-4-isopropylpyridine) and benzaldehyde involving a more unusal type of cleavage of the triazoline formed initially [2]. Perfluoro-(2-azido-4-isopropyl-pyridine) does not react with cyclopentene or cyclohexene upto 110 °C but when the reaction is carried out at the decomposition temperature of the azide i.e. 160 °C, a mixture of the amino compound and the corresponding cyclic ketone is obtained. It is believed that at 160 °C the reaction still proceeds via 1,3-cycloaddition because no evidence of nitrene formation was found when the azide was decomposed thermally or photochemically in the presence of conventional nitrene traps e.g. dimethyl sulphoxide, cyclohexane etc. [2] and only polymeric material was obtained. Perfluoro-(2-azido-4-isopropylpridine) reacts smoothly with norbornene at room temperature with evolution of nitrogen and only the products of decomposition of initially formed triazoline are obtained.