Synthesis of some pyridooxadiazine from pentaflouropyridine

Amidoximes compounds were synthesized from reaction of corresponding nitrile compound with hydroxyl amine [1]. Pentafluoropyridine is a very versatile ―building block‖ because, in principle, all five fluorine substituents in pentafluoropyridine could be substituted by nucleophiles. Therefore, potentially, a range of polysubstitiuted systems could be derived from this core molecule by nucleophilic aromatic substitution processes [2]. Furthermore, it is well established1 that, in general, the order of activation towards nucleophilic attack follows the sequence 4-fluorine 2-fluorine 3-fluorine [3]. In this project we firstly design an easy, efficient and simple approach for the synthesis of some amidoximes from nitriles under ultrasonic irradiation in short reaction times then the reaction of amidoximes with pentafluoropyridine were investigated. Reaction of some amidoximes with pentafluoropyridine in the presence of K2CO3 and in CH3CN as solvent gave corresponding pyridooxadiazines compounds in good yields. The structure of new heterocyclic compounds were confirmed by 1H NMR, 19F NMR and 13C NMR spectra.