Cyclotriphosphazenes having stereogenic phosphorus atoms: Synthesis, characterization and their stereogenic properties

Abstract

Cyclotriphosphazene derivatives (4-6) with stereogenic phosphorus atoms were synthesized to investigate their stereogenic properties. The unsymmetrical reagents 3-amino-1-propanol and N-methyl-1,3propanediamine were used to provide two equivalent stereogenic centers on phosphorus atoms and an unsymmetrical substituted phosphorus atom, respectively. The compounds N3P3[O(CH2)(3)NH](2) [O(CH2)(2)NMe] (4-6) (diastereoisomers) were separated by column chromatography on silica gel and analyzed by elemental analysis, mass spectrometry, and P-31 and H-1 NMR spectroscopies. In addition, the structure of compound 5 was determined by X-ray crystallography. All the compounds (4-6) were analyzed by the changes in the P-31 NMR spectra on addition of the chiral solvating agent (CSA), (R)-(+)-2,2, 2-trifluoro-1-(9'-anthryl)ethariol to investigate their stereogenic properties. The results support that compounds 4-6 are three different diastereoisomers with chiral centres, and whilst compound 4 is racemic, compounds 5 and 6 are meso. (C) 2014 Elsevier Ltd. All rights reserved.