Investigation of nucleophilic substitution pathway for the reactions of 1,4-benzodioxan-6-amine with chlorocyclophosphazenes

•The reactions of cyclophosphazenes with 1,4-benzodioxan-6-amine were investigated.•All new compounds were fully characterization by spectroscopic techniques.•The reaction mechanisms have been investigated by NMR and X-ray.•Cyclotriphosphazenes could be formed by a proton abstraction-chloride elimination mechanism.•Cyclotetraphophazes might be constituted by the SN2 mechanism.

In the present work, a series of 1,4-benzodioxan-6-amino substituted cyclophosphazenes (1–8) were synthesized in order to provide insight into the reaction mechanism for nucleophilic substitution. All compounds were fully characterized by elemental and mass analyses, 1H and 31P NMR spectroscopies. Molecular and crystal structures of 1, 2, 4, 7a and 7c were characterized by X-ray crystallography. While compounds 2 and 4 could be formed by a proton abstraction/chloride elimination mechanism, 1, 6, 7a and 7c could be formed by SN2 mechanism. Compound 3 might be formed by both SN1 and SN2 reaction mechanisms, respectively. These mechanisms were supported by 31P NMR and X-ray crystallography results.

Graphical abstractIn this paper synthesis and characterization of a series of 1,4-benzodioxan-6-amino substituted cyclophosphazene derivatives have been reported.Figure optionsDownload full-size imageDownload as PowerPoint slide