Iwona E. Głowacka

Design, synthesis, antiviral and cytostatic activity of ω-(1H-1,2,3-triazol-1-yl)(polyhydroxy)alkylphosphonates as acyclic nucleotide analogues.

Abstract The efficient synthesis of a new series of polyhydroxylated dibenzyl ω-(1H-1,2,3-triazol-1-yl)alkylphosphonates as acyclic nucleotide analogues is described starting from dibenzyl ω-azido(polyhydroxy)alkylphosphonates and selected alkynes under microwave irradiation. Selected O,O-dibenzylphosphonate acyclonucleotides were transformed into the respective phosphonic acids. All compounds were evaluated in vitro for activity against a broad variety of DNA and RNA viruses and for cytostatic activity against murine leukemia L1210, human T-lymphocyte CEM and human cervix carcinoma HeLa cells. Compound (1S,2S)-16b exhibited antiviral activity against Influenza A H3N2 subtype (EC50 =20μM—visual CPE score; EC50 =18μM—MTS method; MCC >100μM, CC50 >100μM) in Madin Darby canine kidney cell cultures (MDCK), and (1S,2S)-16k was active against vesicular stomatitis virus and respiratory syncytial virus in HeLa cells (EC50 =9 and 12μM, respectively). Moreover, compound (1R,2S)-16l showed activity against both herpes simplex viruses (HSV-1, HSV-2) in HEL cell cultures (EC50 =2.9 and 4μM, respectively) and feline herpes virus in CRFK cells (EC50 =4μM) but at the same time it exhibited cytotoxicity toward uninfected cell (MCC⩾4μM). Several other compounds have been found to inhibit proliferation of L1210, CEM as well as HeLa cells with IC50 in the 4–50μM range. Among them compounds (1S,2S)- and (1R,2S)-16l were the most active (IC50 in the 4–7μM range).

Synthesis and Biological Evaluation of Novel 1,2,3-Triazolonucleotides

A general procedure for the preparation of 1,2,3‐triazole analogs of nucleosides from diethyl 2‐azidoethoxymethyl‐ and 2‐azidoethoxyethylphosphonates was elaborated. The application of microwave irradiation shortened the reaction time to 10 min in comparison to ca. 48 h when 1,3‐dipolar cycloadditions were performed under standard conditions. All compounds were evaluated in vitro for inhibitory activity against a broad variety of DNA and RNA viruses. None of the compounds were antivirally active at subtoxic concentrations. Compound 17k exhibited moderate inhibitory effects on the proliferation of human T‐lymphocyte cells (IC50 = 64 µM for CEM).

Design, synthesis, antiviral, and cytotoxic evaluation of novel phosphonylated 1,2,3-triazoles as acyclic nucleotide analogues.

The 1,3-dipolar cycloaddition of diethyl 2-azidoethyl-, 3-azidopropyl-, 2-azido-1-hydroxyethyl-, 3-azido-2-hydroxypropylphosphonates with selected N-propargyl nucleobases gave a series of the phosphonylated 1,2,3-triazole acyclonucleosides in which the phosphonate residue and nucleobases were linked by three- and four-carbon chains. Under standard conditions (TMSBr, ethanol), all synthesized O,O-diethylphosphonates were transformed into the respective phosphonic acids. All compounds were evaluated in vitro for activity against a broad variety of DNA and RNA viruses. Unfortunately, no antiviral activity was observed at 100 μM.

Synthesis of a new series of phosphonylated 1,2,3-triazoles as acyclic analogs of ribavirin.

A novel series of phosphonylated 1,2,3‐triazoles as structural acyclic analogs of ribavirin, in which the 1,2,3‐triazole ring was substituted at C4′ with COOMe, CONH2, CONHOH, and CH2NHBoc groups, were synthesized from diethyl azidomethyl‐, 2‐azidoethyl‐, 3‐azidopropyl‐, 4‐azidobutyl‐, 2‐azido‐1‐hydroxyethyl‐, 3‐azido‐2‐hydroxypropyl‐, 2‐azidoethoxymethyl‐ and 2‐azidoethoxyethylphosphonate. The efficient synthesis of diethyl azidomethylphosphonate from diethyl 4‐nitrobenzenesulfonylmethylphosphonate employing the in situ formed azides is described. All synthesized compounds were evaluated in vitro for their inhibitory activity against a broad variety of RNA and DNA viruses. No antiviral activity was observed at 100 µM. Only compound 13g exhibited inhibitory effects on the proliferation of HeLa cells (IC50 = 169 ± 45 µM).

Synthesis and the Biological Activity of Phosphonylated 1,2,3-Triazolenaphthalimide Conjugates

A novel series of diethyl {4-[(5-substituted-1,3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)-methyl]-1H-1,2,3-triazol-1-yl}alkylphosphonates designed as analogues of amonafide was synthesized. All phosphonates were assessed for antiviral activity against a broad range of DNA and RNA viruses and several of them showed potency against varicella-zoster virus (VZV) [EC50 (50% effective concentration) = 27.6–91.5 μM]. Compound 16b exhibited the highest activity against a thymidine kinase-deficient (TK−) VZV strain (EC50 = 27.59 μM), while 16d was the most potent towards TK+ VZV (EC50 = 29.91 μM). Cytostatic properties of the compounds 14a–i–17a–i were studied on L1210, CEM, HeLa and HMEC-1 cell lines and most of them were slightly cytostatic for HeLa [IC50 (50% inhibitory concentration) = 29–130 µM] and L1210 cells [IC50 (50% inhibitory concentration) = 14–142 µM].

Novel acyclic phosphonylated 1,2,3-triazolonucleosides with an acetamidomethyl linker: synthesis and biological activity.

A new series of 4‐substituted [(1,2,3‐triazol‐1‐yl)acetamido]methylphosphonates as acyclic nucleotide analogs were synthesized from diethyl (2‐chloroacetamido)methylphosphonate via azidation followed by 1,3‐dipolar cycloaddition with selected alkynes derived from natural nucleobases or their mimetics. All compounds were tested for their antiviral activities against DNA and RNA viruses as well as for cytostatic activity or cytotoxicity. Among all tested compounds, [(1,2,3‐triazol‐1‐yl)acetamido]methylphosphonate 6e substituted with the N3‐Bz‐benzuracil moiety showed activity against the vesicular stomatitis virus (EC50 = 45 µM) in HeLa cell cultures.

Synthesis of Novel 1-Hydroxy-2-(1,2,3-triazol-1-yl)ethylphosphonates and 2-Hydroxy-3-(1,2,3-triazol-1-yl)propylphosphonates

Abstract Several new 1-hydroxy-2-(1,2,3-triazol-1-yl)ethylphosphonates and 2-hydroxy-3-(1,2,3-triazol-1-yl)propylphosphonates as well as the respective phosphonic acids were synthesized from diethyl 1,2-epoxyethylphosphonate and 2,3-epoxypropylphosphonate in the reaction sequence including the regioselective ring opening of the epoxide with azides followed by 1,3-dipolar cycloaddition of ω-azidophosphonates and selected alkynes and finally hydrolyses of the phosphonate esters. 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

1-Amino-3-(1H-1,2,3-triazol-1-yl)propylphosphonates as Acyclic Analogs of Nucleotides

A new series of 1‐amino‐3‐(1H‐1,2,3‐triazol‐1‐yl)propylphosphonates (R)‐ and (S)‐16 were obtained from enantiomerically pure (R)‐ and (S)‐1‐tert‐butoxycarbonyl (Boc)‐amino‐3‐azidopropylphosphonates and N‐propargylated nucleobases in good yields. All 1,2,3‐triazolylphosphonates (R)‐ and (S)‐16 were evaluated for their activities against a broad range of DNA and RNA viruses. Compound (R)‐16g (B = 3‐acetylindole) was moderately active against vesicular stomatitis virus in HeLa cell cultures (EC50 = 45 µM). In addition, (S)‐16c (B = adenine), (R)‐16f (B = N3‐Bz‐benzuracil), (R)‐16g (B = 3‐acetylindole), and (R)‐16h (B = 5,6‐dimethylbenzimidazole) were cytotoxic toward Crandell‐Rees feline kidney (CRFK) cells (CC50 = 2.9, 45, 72, and 96 µM, respectively). Compounds (R)‐16g, (S)‐16g, and (S)‐16h were slightly cytostatic to different tumor cell lines.

Phosphonylated acyclic guanosine analogues with the 1,2,3-triazole linker

A novel series of {4-[(2-amino-6-chloro-9H-purin-9-yl)methyl]-1H-1,2,3-triazol-1-yl}alkylphosphonates and {4-[(2-amino-6-oxo-1,6-dihydro-9H-purin-9-yl)methyl]-1H-1,2,3-triazol-1-yl}alkylphosphonates as acyclic analogues of guanosine were synthesized and assessed for antiviral activity against a broad range of DNA and RNA viruses and for their cytostatic activity toward three cancerous cell lines (HeLa, L1210 and CEM). They were devoid of antiviral activity; however, several phosphonates were found slightly cytostatic against HeLa cells at an IC50 in the 80–210 µM range. Compounds (1R,2S)-17k and (1S,2S)-17k showed the highest inhibitory effects (IC50 = 15–30 µM) against the proliferation of murine leukemia (L1210) and human T-lymphocyte (CEM) cell lines.

Design, Synthesis, and the Biological Evaluation of a New Series of Acyclic 1,2,3-Triazole Nucleosides

A new strategy for the synthesis of N3‐benzoylated‐ and N3‐benzylated N1‐propargylquinazoline‐2,4‐diones 30a−d and 31a−d from isatoic anhydride 41 is reported. The alkynes 30a−d and 31a−d were applied in the 1,3‐dipolar cycloadditions with azides 27 and 28 to synthesize acyclic 1,2,3‐triazole nucleosides. The obtained alkynes and 1,2,3‐triazole were evaluated for antiviral activity against a broad range of DNA and RNA viruses. The alkyne 30d showed activity against adenovirus‐2 (EC50 = 8.3 μM), while compounds 37a and 37d were also active toward herpes simplex virus‐1 wild‐type and thymidine kinase deficient (HSV‐1 TK−) strains (EC50 values in the range of 4.6–13.8 μM). In addition, compounds 30a, 30b, 37b, and 37c exhibited activity toward varicella‐zoster virus (VZV) TK+ and TK− strains (EC50 = 2.1–9.5 μM). The compound 30b proved to be the most selective against VZV and displayed marginal activity against human cytomegalovirus (HCMV). Although the compound 30a had improved anti‐HCMV activity, the increase in anti‐HCMV activity was accompanied by significant toxicity. Compounds 37a and 37d showed inhibitory effects toward the human T lymphocyte (CEM) cell line (IC50 = 21 ± 7 and 22 ± 1 μM, respectively), while compound 35 exhibited cytostatic activity toward HMEC‐1 cells (IC50 = 28 ± 2 μM).