Synthesis and Evaluation of cis-1-[4-(Hydroxymethyl)-2-cyclopenten-1-yl]-5-[124I]iodouracil: A New Potential PET Imaging Agent for HSV1-tk Expression

Synthesis of functionalized cyclopentenes through allenic ketone-based multicomponent reactions

A novel and efficient synthesis of diversely functionalized cyclopentene derivatives through the multicomponent reactions of 1,2-allenic ketones with 4-chloroacetoacetate and malononitrile/cyanoacetate under mild and metal-free conditions is presented. Mechanistically, the formation of title compounds involves a cascade process including nucleophilic substitution, Michael addition and intramolecular aldol type reaction. Interestingly, when 1-phenyl allenic ketones bearing electron-donating groups on the phenyl ring were reacted with 4-chloroacetoacetate and cyanoacetate, methylenecyclo-pentanes, the regioisomer of cyclopentenes, were formed with good selectivity and high efficiency.

Nucleobase azide-ethynylribose click chemistry contributes to stabilizing oligonucleotide duplexes and stem-loop structures

The formation of 1,4-disubstituted 1,2,3-triazoles through copper-catalyzed azide-alkyne cycloaddition (CuAAC) in oligonucleotides bearing 1-deoxy-1-ethynyl-β-d-ribofuranose (R^E) can have a positive impact on the stability of oligonucleotide duplexes and stem-loop structures.

Direct Regioselective [3 + 2]-Cyclization Reactions of Ambivalent Electrophilic/Nucleophilic β-Chlorovinyl Dithianes: Access to Cyclopentene Derivatives

The highly regioselective and operationally straightforward [3 + 2] cyclizations of β-chlorovinyl dithianes with α,β-unsaturated carbonyl compounds have been developed. This protocol provides direct access to highly functionalized cyclopentenes with perfect chemo- and regioselectivities under extremely mild reaction conditions. In particular, the unprecedented cyclization allows for the selective preparation of hydroxylated cyclopentenes.

Thymidine kinase enzyme selective imaging radiopharmaceutical: 99mTc(CO)3-Ganciclovir

The aim of this study is to radiolabel ganciclovir, known as having selective antiviral properties against thymidine kinase, with technetium tricarbonylcore (99mTc(CO)3 +) and to investigate the biological behavior of this complex in vitro and in vivo. Commercially provided Ganciclovir (GCV) was radiolabeled with 99mTc(CO)3 +. Initially, optimum radiolabeling conditions were determined by analyzing factors such as temperature, pH and time. Quality control of the radiolabeled compound was performed. The radiolabeling yield was found to be 97%. The 99mTc(CO)3-GCV complex also displayed good in vitro stability during the 24 h period. In vitro cell uptake studies showed that the 99mTc(CO)3-GCV complex is highly uptaken in A-549, PC-3, HeLa cell lines according to the control group 99mTc(I)-tricarbonyl core. The knowledge gained from in vivo and in vitro studies of 99mTc(CO)3-GCV could contribute to the development of a new HSV1-tk gene imaging agent.

1,2,3-Triazole-containing uracil derivatives with excellent pharmacokinetics as a novel class of potent human deoxyuridine triphosphatase inhibitors

Deoxyuridine triphosphatase (dUTPase) has emerged as a potential target for drug development as a 5-fluorouracil-based combination chemotherapy. We describe the design and synthesis of a novel class of human dUTPase inhibitors, 1,2,3-triazole-containing uracil derivatives. Compound 45a, which possesses 1,5-disubstituted 1,2,3-triazole moiety that mimics the amide bond of tert-amide-containing inhibitor 6b locked in a cis conformation showed potent inhibitory activity, and its structure-activity relationship studies led us to the discovery of highly potent inhibitors 48c and 50c (IC(50) = ~0.029 μM). These derivatives dramatically enhanced the growth inhibition activity of 5-fluoro-2'-deoxyuridine against HeLa S3 cells in vitro (EC(50) = ~0.05 μM). In addition, compound 50c exhibited a markedly improved pharmacokinetic profile as a result of the introduction of a benzylic hydroxy group and significantly enhanced the antitumor activity of 5-fluorouracil against human breast cancer MX-1 xenograft model in mice. These data indicate that 50c is a promising candidate for combination cancer chemotherapies with TS inhibitors.

Enantioselective synthesis of homo-N-nucleosides containing a 1,4-dioxane sugar analog

A dioxane homo-sugar analog, (2S,5S)-and (2R,5S)-5-[(4S)-2,2-dimethyl-1,3-dioxolan-4-yl]-2-iodomethyl-1,4-dioxane was prepared from (2R,3R)-dimethyl tartrate, and further elaborated into the corresponding homo-N-nucleoside analogs by its reactions with uracil and adenine, respectively.