Ivelina Tsacheva

Synthesis, antiproliferative activity and genotoxicity of novel anthracene-containing aminophosphonates and a new anthracene-derived Schiff base.

A new Schiff base, 9-anthrylidene-furfurylamine and three novel anthracene-containing α-aminophosphonates, [N-methyl(dimethoxyphosphonyl)-1-(9-anthryl)]-p-toluidine, [N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]-p-toluidine and [N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]furfurylamine were synthesized. The compounds have been characterized by elemental analysis, TLC, IR, NMR and fluorescent spectra. The aminophosphonates and their synthetic precursors were tested for in vitro antitumor activity on a panel of seven human epithelial cancer cell lines. Safety testing was performed both in vitro (3T3 NRU test) and in vivo on ICR mice for genotoxicity and antiproliferative activity. 9-Anthrylidene-furfurylamine and [N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]furfurylamine were most potent cytotoxic agents towards colon carcinoma cell line HT-29. The latter compound exhibited also antiproliferative activity to HBL-100, MDA-MB-231 and 647-V cells. The aminophosphonate [N-methyl(dimethoxyphosphonyl)-1-(9-anthryl)]-p-toluidine and its synthetic precursor 9-anthrylidene-p-toluidine were found to be cytotoxic to HBL-100 and HT-29 tumor cell lines, respectively. Moderate genotoxic and antiproliferative activity in vivo and low toxicity to Balb/c 3T3 (clone 31) mouse embryo cells were observed for all tested compounds. The subcellular distribution of two tested compounds in a tumor cell culture system was also studied.

Synthesis, characterization, antitumor activity and safety testing of novel polyphosphoesters bearing anthracene-derived aminophosphonate units

Novel polyphosphoesters containing anthracene-derived aminophosphonate units, poly(oxyethylene aminophosphonate)s (4 and 5) and poly[oxyethylene(aminophosphonate-co-H-phosphonate)]s (6 and 7), were synthesized via an addition of poly(oxyethylene H-phosphonate)s to 9-anthrylidene-p-toluidine. The IR, NMR ((1)H, (13)C and (31)P) and fluorescence emission spectral data of the polymers are presented. The copolymers 6 and 7 were tested for in vitro antitumor activity on a panel of seven human epithelial cancer cell lines. Safety testing was performed both in vitro (3T3 NRU test) and in vivo on ICR mice for genotoxicity and antiproliferative activity. The copolymer 7 showed excellent antiproliferative activity to HBL-100, MDA-MB-231, MCF-7 and HepG2 cell lines. However, the in vitro safety testing revealed significant toxicity to Balb/c 3T3 mouse embryo cells. In contrast, the copolymer 6 showed complete absence of cytotoxicity to Balb/c 3T3 cells, but inhibited the growth of breast cancer cells, cervical carcinoma cells (HeLa) and hepatocellular carcinoma cell cultures after prolonged (72h) exposure. The polymers (4-6) exhibited low (4 and 6) to moderate (5) clastogenicity in vivo and slightly inhibited bone marrow cell division, compared to Mitomycin C. The subcellular distribution of the copolymers 6 and 7 were studied in model cell culture systems. The tested polyphosphoesters are expected to act in vivo as prodrugs of aminophosphonates and could be valuable as a new class of biodegradable polymer drug carriers.

Anthracene-Derived Bis-Aminophosphonates: Crystal Structure, In Vitro Antitumor Activity, and Genotoxicity In Vivo

Abstract The X-ray crystal structures of the anthracene-derived bis-aminophosphonates 4.4′-bis[N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]diaminodiphenylmethane (1) and 1,3-bis [N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]diaminobenzene (3) are reported. The X-ray analyses demonstrated that both compounds crystallize in a centrosymmetric manner containing a meso-form (1) and a pair of enantiomers (3). The cytotoxic potential, genotoxicity, and antiproliferative activity of bis-aminophosphonates 1 and bis[N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]benzidine (2), as well as their subcellular distribution in a tumor cell culture system, are also discussed. Compounds 1 and 2 showed optimal antiproliferative activity to human tumor cells from colon carcinoma line HT-29. In vitro and in vivo safety testing revealed that the compounds exert lower toxicity to normal cells as compared with well-known anticancer and cytotoxic agents. Supplemental materials are available for this article. Go to the publishers online edition ofPhosphorus, Sulfur, and Silicon and the Related Elementsto view the free supplemental file. GRAPHICAL ABSTRACT

Polymer complex of WR 2721. Synthesis and radioprotective efficiency

Polymer complex constructed from WR 2721 and poly(hydroxyoxyethylene phosphate) was synthesized. The structure of complex formed was elucidated by (1)H-, (13)C, (31)P NMR and FT-IR spectroscopy. The radioprotector was immobilized via ionic bonds. Radioprotective efficacy was evaluated by clonal survival of stem cells in crypts of mouse small intestine, and incidence and latency of the acute radiation induced bone marrow syndrome. Protection factors were assessed for WR 2721 and for the polymer complex. Protection factors for the polymer complex ranged from 2.6 for intestinal stem cell survival to 1.35 for 30 day survival (LD50) following whole body radiation exposure. In all cases, the polymer complex was a significantly better radiation protector than the parent compound.

Synthesis and NMR Characterization of Two Novel Anthracene-Derived BIS-Aminophosphonates. Basic Hydrolysis of Some Aminophosphonate Derivatives

Abstract The synthesis of two novel bis-aminophosphonates bearing anthracene rings – bis[N- methyl(diethoxyphosphonyl)-1-(9-anthryl)]benzidine (3) and 4,4′-bis[N-methyl(diethoxy-phosphonyl)-1-(9-anthryl)]diaminodiphenylmethane (4) – via the Kabachnik–Fields reaction is reported. The compounds have been characterized by elemental analysis, TLC, IR, NMR (1H, 13C, 31P) and fluorescent spectra. The reaction leads to a mixture of the two possible forms (meso and racemic), with predominant formation of one of the diastereomers. The recrystallized compounds 3 and 4 consist of only one diastereomer. A racemization at the chiral centers and a cleavage of the C-P bond are observed in the alkaline hydrolysis of the new compound 4 and three previously described aminophosphonate derivatives 5–7. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Diethyl [(9-anthr­yl)(4-methyl­anilino)meth­yl]phospho­nate

The title compound, C26H28NO3P, crystallized with two independent molecules in the asymmetric unit. The structural features (bond lengths and angles) of the two molecules are almost identical. The interplanar angle between the anthracene and toluidine rings is similar in the two molecules, with values of 82.92 (5) and 80.70 (5)°. In the crystal, both molecules form inversion dimers linked by pairs of N—H⋯O hydrogen bonds. Three of the four ethyl groups are disordered over two sets of sites, the major components having occupancies of 0.748 (15), 0.77 (4) and 0.518 (19).

Microwave assisted synthesis and X-ray structure of a novel anthracene-derived aminophosphonate. Enantioseparation of two α-aminophosphonates and genotoxicity in vivo

GRAPHICAL ABSTRACT ABSTRACT A novel anthracene-derived α-aminophosphonate has been synthesized through a classical addition reaction of dimethyl phosphite to a Schiff base and via a microwave assisted Kabachnik–Fields reaction. The compound has been characterized by elemental analysis, TLC, IR, NMR, and fluorescent spectra. The X-ray analysis showed that the compound crystallizes in the orthorhombic space group Pbca (N° 61) with one molecule per asymmetric unit. The enantioseparation of two racemic aminophosphonates (5 and 6) into enantiomers (5a, 5b and 6a, 6b, respectively) has been performed. Data about genotoxicity and antiproliferative activity in vivo of the racemic compounds and their enantiomeric forms is also presented. The studied racemic α-aminophosphonates 5 and 6 and their enantiomers have weak genotoxic effect. Both pairs of enantiomers did not show a significant inhibition of cell dividing processes in the bone marrow cells compared to 5 and 6. The hematopoietic function of the bone marrow will not be discontinued after exposure of the tested compounds.

Low cytotoxicity and clastogenicity of some polymeric aminophosphonate derivatives

Poly(oxyethylene aminophosphonate)s synthesized on the basis of biodegradable poly(phosphorester)s and Schiff bases were tested in vitro for antitumor activity against a panel of six human epithelial cancer cell lines, for cytotoxicity to mouse fibroblast cells and in vivo for clastogenicity and antiproliferative effects. The polymers showed lower cytotoxicity, both in vivo and in vitro and lower clastogenicity in vivo than the corresponding low-molecular aminophosphonates. The biological activities of the tested polymers correlate with their low in vitro antitumor activity.

In vitro antitumour activity, genotoxicity, and antiproliferative effects of aminophosphonic acid diesters and their synthetic precursors.

The Schiff bases N-furfurylidene-p-toluidine and N-(4-dimethylaminobenzilidene)- p-toluidine, and the recently synthesized aminophosphonic acid diesters p-[N-methyl- (diethoxyphosphonyl)-(2-furyl)]toluidine and p-[N-methyl(diethoxyphosphonyl)-(4-dimethylaminophenyl)] toluidine were tested for in vitro antitumour activity on six human epithelial cancer cell lines. The genotoxicity and antiproliferative activity of these compounds were tested in mice. The aminophosphonates showed high in vitro antitumour activity towards the breast cancer-derived cell lines (MCF-7 and MDA-MB-231), the cervical carcinoma cell line (HeLa), and the human colon adenocarcinoma cell line (HT-29). In addition, the Schiff base N-furfurylidene-p-toluidine significantly inhibited the growth of bladder carcinoma cells (647-V) and the hepatocellular carcinoma line HepG2, and U-shaped dose-response curves were observed after treatment of 647-V and MCF-7 cells. All studied compounds had a moderate genotoxic and antiproliferative activity in vivo

Synthesis of Two Novel Homologous Polyphosphoesters Containing Aminophosphonate Units and Cytotoxicity of Some Low-Molecular and Polymeric Aminophosphonate Derivatives

Two novel polyphosphoesters containing anthracene- and furan-derived aminophosphonate moieties, namely, poly[oxyethylene(aminophosphonate-co-H-phosphonate)]s P-12 and P-13, were synthesized through an addition of poly(oxyethylene H-phosphonate) to 9-anthrylidene-furfurylamine and characterized. The novel polyphosphoester P-12 and a series of previously described anthracene-derived compounds including Schiff bases S-1 and S-2, α-aminophosphonates A-3–A-6, bis-aminophosphonate B-6, two enantiomers A-5a and A-5b, and polyphosphoesters P-8–P-11 containing aminophosphonate units were screened for antitumor activity against a panel of human leukemic cell lines, using cisplatin as a reference cytotoxic agent. As concluded from the cytotoxicity assays, both precursors S-1 and S-2 presented similar cytotoxicity profiles that are cisplatin-like only in the REH cell line. Leader compound of the α-aminophosphonates is A-4 with cell death-inducing properties fully equaling those of the referent drug in all of the screened leukemic cell lines with the only exception being the AML histological subtype HL-60. Some of the polymeric analogues elicited moderate (P-10 and P-12) to low (P-11) cytotoxic activity, whereas the polyphosphoesters P-8 and P-9 produced in vitro antitumor effects largely surpassing cisplatin’s. The compounds P-8, P-9, and A-4 could be potential new materials for anticancer therapeutic purposed.