The reactions of N3P3Cl6 with monodentate and bidentate ligands: the syntheses and structural characterizations, in vitro antimicrobial activities, and DNA interactions of 4-fluorobenzyl (N/O) spirocyclotriphosphazenes

Abstract

The Cl replacement reactions of 4-fluorobenzyl(N/O)spirocyclotriphosphazene (2) with excess monoamines led to the formation of 4-fluorobenzylspiro(N/O)tetraaminocyclotriphosphazenes (2a-2d). The partly substituted \textbf{dispiro 3b and dispiro 3c and fully substituted trispirocyclotriphosphazenes (trans 4a, cis 4c, 4d, and 4e) were obtained, respectively, from the reactions of 2 with one equimolar and two equimolar amounts of diamines, aminoalcohol, and diols. Although efforts were made for the separation of the cis/trans and optical isomers of the dispiro phosphazenes, only one set of diastereomers (RR/RS or SS/SR) of dispiro 3b and dispiro 3c was isolated, respectively. The $^{31}$P NMR spectral data of the other dispiro phosphazenes were evaluated from the $^{31}$P NMR spectra of the reaction mixtures. The reactions of 2 with excess N-methylethylenediamine gave trans 4a as a racemic mixture. While trans 4b (racemic) and cis 4b (meso) occurred from the reaction of 2 with excess N-methyl-1,3-propanediamine, they were not isolated separately. Some of the phosphazenes were screened against bacteria and fungi. The activities of the compounds against anaerobic and microaerophilic gram-negative bacteria were evaluated. It was found that compounds 2, 2b, and trans 4a exhibited tolerable toxic effects on fibroblast cells and had the highest toxicity against MCF-7 cells.