Regional selectivity of 1,2-ethanediol in the reactions with cyclotriphosphazene derivatives bearing mono-amino groups

Abstract

In the present work, the reactions of mono primary and secondary amino substituted cyclotriphosphazene derivatives (1a–c) with 1,2-ethanediol were investigated to determine the effects of the amino groups substituted to cyclotriphosphazene [P3N3Cl5(NHR/NR′2); R = i-propyl (1a), tert-butyl (1b), R′ = dimethyl (1c)] on the reaction pathway. These reactions led to five new cyclotriphosphazene compounds: single-bridged, (2a, 2b), mono-ansa (3a, 3b) and mono-spiro (4c). The all products were characterized by elemental analysis, mass spectrometry, 1H and 31P NMR spectroscopy. In addition, the structures of 2a and 4c were characterized by X-Ray crystallography. Although there are different reaction pathways (intramolecular and intermolecular interaction) for the reactions of primary amino substituted cyclotriphosphazene compounds (1a–b) with 1,2-ethanediol, secondary amino substituted cyclotriphosphazene derivative (1c) follows only one reaction pathway (intramolecular interaction). Compounds 2a, 2b, 3a and 3b could be constituted with proton abstraction/chloride elimination whereas 4c may be formed by the both SN2 and SN1 reaction mechanisms.