Synthesis and Antiviral Activity of the Carbocyclic Analogue of the Highly Potent and Selective Anti-VZV Bicyclo Furano Pyrimidines

A Comprehensive Analysis of the Thrombin Binding Aptamer Containing Functionalized Pyrrolo-2'-deoxycytidines

Aptamers constitute an answer for the growing need for targeted therapy development. One of the most well-known representatives of this group of compounds is thrombin binding aptamers (TBA) targeted towards thrombin. The TBA inhibitory activity is determined by its spatial arrangement, which consists of two G-tetrads linked by two shorter TT loops and one longer TGT loop and folds into a unimolecular, antiparallel G-quadruplex structure. Interesting properties of the aptamer can be further improved via the introduction of a number of chemical modifications. Herein, a comprehensive analysis of the influence of pyrrolo-2’-deoxycytidine (Py-dC) and its derivatives on TBA physicochemical and biological properties has been presented. The studies have shown that the presence of modified residues at the T7 position of the TGT loop has only minor effects on TBA thermodynamic stability without affecting its folding topology. All analyzed oligomers exhibit anticoagulant properties, but only aptamer modified with a decyl derivative of Py-dC was able to inhibit thrombin activity more efficiently than unmodified, parental compounds. Importantly, the same compound also possessed the potential to effectively restrain HeLa cell line growth.

Access to 1'-Amino Carbocyclic Phosphoramidite to Enable Postsynthetic Functionalization of Oligonucleotides

We report a synthesis of a carbocyclic, abasic RNA phosphoramidite decorated with an amino functionality. The building block was efficiently incorporated into an RNA oligonucleotide in a site-specific manner, followed by deprotection to a free amino group. The amino moiety could be further derivatized as exemplified with fluorescein N-hydroxysuccinimide ester. Hence, this convertible building block may provide access to a variety of RNA oligonucleotides via postsynthetic amino group functionalization. In particular, providing a vector toward nucleobase replacements.

Synthesis, Structure and Antimicrobial Activity of Novel Metabolites from a Marine Actinomycete in Vietnam's East Sea

A naturally new ester, 2,4-dichlorophenyl 2,4-dichloro benzoate (1) and a new compound, 4,5-dihydroxy-7-methylphthalide (2), along with eight known compounds were isolated from the fermentation broth of the marine-derived actinomycete Streptomyces sp. (strain G212). The structures of these compounds were established by their spectral data analysis, including MS, and 2D-NMR. To confirm the structures of the two new compounds 1 and 2, their total syntheses were achieved. These syntheses also allow obtaining enough quantities of 1 and 2 for their biological screening. The isolated compounds and synthetic samples were evaluated for their antimicrobial activity against a panel of clinically significant microorganisms. Except for 8 and 10, the remaining compounds were active against at least one tested microbial strain with the MIC values in range of 32-256 μg/mL. Compounds 5, 6, 17 and 2a were found to have a broad-spectrum of antimicrobial activity.

Novel 5'-Norcarbocyclic Derivatives of Bicyclic Pyrrolo- and Furano[2,3-d]Pyrimidine Nucleosides

Here we report the synthesis and biological activity of new 5′-norcarbocyclic derivatives of bicyclic pyrrolo- and furano[2,3-d]pyrimidines with different substituents in the heterocyclic ring. Lead compound 3i, containing 6-pentylphenyl substituent, displays inhibitory activity with respect to a number of tumor cells with a moderate selectivity index value. Compound 3i induces cell death by the apoptosis pathway with the dissipation of mitochondrial potential.

Regio- and Stereoselective Synthesis of Functionalized Cyclopentene Derivatives via Mizoroki-Heck Reactions

Pd(0)-catalyzed Mizoroki-Heck alkenylations and arylations of protected aminocyclopentenes, prepared in a few steps from Vince lactam, afforded functionalized cyclopentenes in high yields and stereoselectivities. DFT calculations were performed to rationalize the high diastereoselectivities. Functionalized cyclopentene products were transformed into valuable chiral building blocks, such as cyclic γ-amino acids and carbocyclic nucleoside precursors.

Evaluation of Novel Phosphoramidate ProTides of the 2′-Fluoro Derivatives of a Potent Anti-Varicella Zoster Virus Bicyclic Nucleoside Analogue

Background:

Recently, the synthesis and antiviral activity of a series of 2′-fluoro derivatives of the most potent anti-varicella zoster virus (VZV) agent reported to date, the bicyclic nucleoside analogue Cf1743, have been reported.

Methods:

Here, we present molecular modelling studies for the interaction of these compounds with VZV-encoded thymidine kinase (TK) and we report the synthesis of a series of phosphoramidate ProTides of these compounds designed to bypass the nucleoside kinase dependence of the parent nucleoside analogues.

Results:

The phosphoramidate prodrugs were equally effective as their parent compounds against VZV in cell culture, but lost antiviral potency against TK-deficient VZV strains.

Conclusions:

ProTide-based kinase bypass is not successful in this case.

FV-100: The Most Potent and Selective Anti-Varicella Zoster Virus Agent Reported to Date

Bicyclic aryl furano pyrimidines represent the most potent anti-varicella zoster virus (VZV) agents reported to date. Lead compounds have 50% effective concentration (EC50) values in vitro that are in the subnanomolar range and selectivity index values that exceed 1 million. They have an absolute requirement for VZV thymidine kinase and most likely act as their phosphate forms. Some structural modification (such as aryl substitution in the base moiety) is tolerated, whereas little sugar modification is acceptable.

The Cf1743 compound has proved to be significantly more potent than all reference anti-VZV compounds, as measured either by inhibition of infectious virus particles and/or viral DNA production; however, the high lipophilicity and very low water solubility of this compound gives poor oral bioavailability (<14%). Use of the modified cyclodextrin captisol and the synthesis of the 5′-monophosphate prodrug of Cf1743 has significantly improved water solubility, but does not give any enhancement in oral bioavailability. By contrast, the synthesis of the ether series does not give any further improvement in terms of solubility. The most promising prodrug to emerge to date is the hydrochloric salt of the 5′-valyl-ester, designated as FV-100. Its uptake into cells has been studied using fluorescent microscopy and biological assays, which have indicated that the compound is efficiently taken up by the cells after a short period of incubation.

2'-Fluorosugar analogues of the highly potent anti-varicella-zoster virus bicyclic nucleoside analogue (BCNA) Cf 1743

We report the preparation of 2'-alpha-F, 2'-beta-F and 2',2'-difluoro analogues of the leading anti-varicella zoster virus (VZV) pentylphenyl BCNA Cf 1743. VZV thymidine kinase showed the highest phosphorylating capacity for the beta-fluoro derivative, that retained equal antiviral potency as the parent compound. In contrast, the alpha-fluoro- and 2',2'-difluoro BCNA derivatives were markedly less (approximately 100-fold) antivirally active.