Aytuğ Okumuş

Phosphorus–nitrogen compounds part 27. Syntheses, structural characterizations, antimicrobial and cytotoxic activities, and DNA interactions of new phosphazenes bearing secondary amino and pendant (4-fluorobenzyl)spiro groups

A number of partly (7-9) and fully (10a-12d, Scheme 1) substituted mono(4-fluorobenzyl)spiro cyclotriphosphazenes was prepared. The structures of the compounds were determined by MS, FTIR, 1D and 2D NMR techniques. The crystal structures of 9, 11b and 12b were verified by X-ray diffraction analysis. In vitro cytotoxic activity of the phosphazenes (10a-12d) against HeLa cervical cancer cell lines was evaluated. Compound 12c was found to be the most effective, as it is a cytotoxic reagent that might activate apoptosis by altering mitochondrial membrane potential. Compounds 10b, 11b and 12b showed very good activity against yeast strains Candida tropicalis and Candida albicans. BamHI and HindIII digestion results demonstrate that the compounds (10a-12a, 10b-12b, 10d-12d), and (9, 10c-12c) bind with G/G and A/A nucleotides, respectively.

Syntheses, structural characterization and biological activities of spiro-ansa-spiro-cyclotriphosphazenes

The replacement reactions of the Cl-atoms in partly substituted spiro-ansa-spiro-cyclotriphosphazenes (7 and 8) with excess pyrrolidine, 4-(2-aminoethyl)morpholine, and 1,4-dioxa-8-azaspiro[4,5]decane in dry THF led to the formation of heterocyclic amine substituted cyclotriphosphazenes (9a–c and 10a–c). All cyclotriphosphazene derivatives were characterized by elemental analysis, FTIR, MS, 1D 1H, 13C and 31P NMR and 2D HSQC, and HMBC techniques, and the crystal structure of partly substituted cyclotriphosphazene 8 was verified by X-ray diffraction analysis. Cyclotriphosphazene derivatives (5–8, 9a–c, and 10a–c) were subjected to antimicrobial activity against seven clinic bacteria and one yeast strain, and the interactions of the phosphazenes with plasmid pBR322 DNA were investigated. Phosphazene derivatives [(5, 7, 8, 9b and 9c) and (10a and 10b)] caused a slight increase and substantial decrease in the mobility of form I DNA, respectively, while 9a caused retardation on gel. Cytotoxic, apoptotic and necrotic effects against L929 fibroblast and A549 lung cancer cells were also evaluated. While the highest toxic effect was obtained for 9a in L929 fibroblast cells and for 9c in A549 lung cancer cells at 100 μg mL−1 concentration, the highest apoptotic effect was determined for 10a in L929 fibroblast cells and for 9a in A549 lung cancer cells at the same concentration. It was found that 9a and 10b exhibited the most necrotic effects against L929 fibroblast and A549 lung cancer cells, respectively. The toxic and necrotic effects of the phosphazenes against A549 lung cancer cells were greater than those against L929 fibroblast cells, whereas, the apoptotic effect of the compounds was greater in L929 fibroblast cells than in A549 lung cancer cells.

Phosphorus–nitrogen compounds. Part 35. Syntheses, spectroscopic and electrochemical properties, and antituberculosis, antimicrobial and cytotoxic activities of mono-ferrocenyl-spirocyclotetraphosphazenes

The reactions of octachlorocyclotetraphosphazene, N4P4Cl8, with N-alkyl-N-mono-ferrocenyldiamines, FcCH2NH(CH2)nNHR1 [n = 2, Fc = ferrocene, R1 = Me (1); n = 2, R1 = Et (2) and n = 3, R1 = Me (3)], led to the formation of monoferrocenyl-spirocyclotetraphosphazenes (4–6). When the reactions were carried out with excess pyrrolidine, morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD), the fully substituted products (4a–6c) were obtained in high yields. The structures of all the phosphazene derivatives were characterized by MS, FTIR, 1H, 13C and 31P NMR, HSQC and HMBC techniques. The crystal structures of 4a and 5a were determined by X-ray crystallography. The electrochemically reversible one-electron oxidation of Fc redox centers was observed for cyclotetraphosphazenes. The fully substituted phosphazenes (4a–6c) were evaluated for their antituberculosis activity against reference strain Mycobacterium tuberculosis H37Rv, and compounds 4a–6a and 5c were found to be active. The antibacterial activities of phosphazenes 4a–6c against G(+) and G(−) bacteria and their antifungal activities against yeast strains were carefully scrutinized. The results indicate that compounds 4a–6a, 6b, 4c and 5c are very effective against yeast strains. The anticandidal activities of 6a and 6b make them promising anticandidal agents. The interactions of these compounds with plasmid DNA and their cytotoxic activity against L929 fibroblast and DLD-1 colon cancer cell lines were also investigated.

Phosphorus–nitrogen compounds. Part 37. Syntheses and structural characterizations, biological activities of mono and bis(4-fluorobenzyl)spirocyclotetraphosphazenes

The Cl substitution reactions of octachlorocyclotetraphosphazene, N4P4Cl8, with one equimolar amount of (4-fluorobenzyl)diamines (1–3) affords mono(4-fluorobenzyl)spirocyclotetraphosphazenes (4–6) as minor products. However, the reactions of N4P4Cl8 with two equimolar amounts of (4-fluorobenzyl)diamines (1–3) leads to the formation of mono (4–6), 2-trans-6-bis (7–9, as major products) and 2-cis-6-bis (4-fluorobenzyl)spirocyclotetraphosphazenes (10–12). The 2-cis-6-bis compounds (10 and 12) were separated and purified using column chromatography as minor products, whereas compound 11 could not be isolated. The mono-spiro (4–6) and 2-trans-6-bis-spiro (7–9) cyclotetraphosphazenes were reacted with excess pyrrolidine in THF to afford the fully substituted hexapyrrolidino (4a-6a) and tetrapyrrolidino (7a-9a) products in high yield. Compound 9 was also reacted with piperidine, morpholine and 1,4-dioxa-8-azaspiro[4,5]decane (DASD) to obtain the tetraamino products (9b, 9c and 9d), respectively, due to its very high yield. The elemental analyses, mass spectra (ESI-MS), Fourier transform infrared (FTIR) spectra, and 1H, 13C{1H}, and 31P{1H} NMR data of the cyclotetraphosphazenes were in agreement with the suggested structures. The molecular structures of 7, 9 and 12 were established by X-ray crystallography. The antibacterial activities of the compounds against G(+) and G(−) bacteria and their antifungal activities against yeast strains were scrutinized. The results indicated that 4a and 5a were the most active compounds, especially to yeast strains. In addition, it was found that the most active compound toward DNA was 8. The cytotoxic activities of the cyclotetraphosphazenes against L929 fibroblast and MCF-7 breast cancer cell lines were elucidated. Compound 8a exhibited the most toxic effects against both types of cells.