Determining Essential Requirements for Fluorophore Selection in Various Fluorescence Applications Taking Advantage of Diverse Structure-Fluorescence Information of Chromone Derivatives.

Herein, we report our work exploring the essential requirements for fluorophore selection during the development of various fluorescence applications. We assembled a library of chromone-derived fluorophores with diverse structure-fluorescence properties, which allowed us to choose the fluorophore pairs with similar structures but differing fluorescence properties and compared the performance of the selected fluorophore pairs in three types of commonly used fluorescence applications. We found that the selection standard of a suitable fluorophore is variable depending on the application. (1) In fluorescence imaging, fluorophores with strong and constant fluorescence under various conditions, such as a large pH range, are preferred. Notably, (2) in the detection of bioactive species, fluorophores with relatively lower fluorescence quantum yield favor the detection sensitivity. Furthermore, (3) in enzymatic assays employing fluorescence, the key parameter is the binding affinity between the fluorophore and the enzyme.

Synthesis and antitumor activity of novel 2',3'-dideoxy-2',3'-diethanethionucleosides bearing 1,2,3-triazole residues.

A series of novel 2',3'-dideoxy-2',3'-diethanethioribonucleosides and those modified with a triazole ring were prepared in excellent yields and their antitumor activity was evaluated. Nucleosides with a triazole ring, 16a-16c, showed significantly improved activity towards a broad range of tumor cell lines.

Near-Infrared Light Irradiation Induced Mild Hyperthermia Enhances Glutathione Depletion and DNA Interstrand Cross-Link Formation for Efficient Chemotherapy.

DNA alkylating agents generally kill tumor cells by covalently binding with DNA to form interstrand or intrastrand cross-links. However, in the case of cisplatin, only a few DNA adducts (<1%) are highly toxic irreparable interstrand cross-links. Furthermore, cisplatin is rapidly detoxified by high levels of intracellular thiols such as glutathione (GSH). Since the discovery of its mechanism of action, people have been looking for ways to directly and efficiently remove intracellular GSH and increase interstrand cross-links to improve drug efficacy and overcome resistance, but there has been little breakthrough. Herein, we hypothesized that the anticancer efficiency of cisplatin can be enhanced through iodo-thiol click chemistry mediated GSH depletion and increased formation of DNA interstrand cross-links via mild hyperthermia triggered by near-infrared (NIR) light. This was achieved by preparing an amphiphilic polymer with platinum(IV) (Pt(IV)) prodrugs and pendant iodine atoms (iodides). The polymer was further used to encapsulate IR780 and assembled into Pt-I-IR780 nanoparticles. Induction of mild hyperthermia (43 °C) at the tumor site by NIR light irradiation had three effects: (1) it accelerated the GSH-mediated reduction of Pt(IV) in the polymer main chain to platinum(II) (Pt(II)); (2) it boosted the iodo-thiol substitution click reaction between GSH and iodide, thereby attenuating the GSH-mediated detoxification of cisplatin; (3) it increased the proportion of highly toxic and irreparable Pt-DNA interstrand cross-links. Therefore, we find that mild hyperthermia induced via NIR irradiation can enhance the killing of cancer cells and reduce the tumor burden, thus delivering efficient chemotherapy.

(R)-2-[(R)-2,2-Dimethyl-1,3-dioxolan-4-yl]-1,3-oxathio-lan-5-one.

In the title compound, C(8)H(12)O(4)S, the two five-membered rings both adopt envelope conformations. In the crystal, weak C-H⋯O inter-actions link neighbouring mol-ecules.

4,5,6-Tri-O-acetyl-2,3-di-S-ethyl-2,3-dithio-d-allose diethyl dithio-acetal.

The title compound, C(20)H(36)O(6)S(4), was obtained by ethanethiol-ysis of 3,5,6-tri-O-acetyl-1,2-O-isopropyl-idene-α-d-gluco-furan--ose. One of the ethyl groups is disordered over two sites with refined occupancies of 0.869 (6) and 0.131 (6). Compared with the precursor, the absolute configuration of the stereocenters at positions C-3 and C-2 are inverted and maintained, respectively.

Synthesis, Anti-Varicella-Zoster Virus and Anti-Cytomegalovirus Activity of 4,5-Disubstituted 1,2,3-(1H)-Triazoles.

BACKGROUND: Clinical drugs for herpesvirus exhibit high toxicity and suffer from significant drug resistance. The development of new, effective, and safe anti-herpesvirus agents with different mechanisms of action is greatly required. OBJECTIVE: Novel inhibitors against herpesvirus with different mechanisms of action from that of clinical drugs. METHODS: A series of novel 5-(benzylamino)-1H-1,2,3-triazole-4-carboxamides were efficiently synthesized and EC50 values against Human Cytomegalovirus (HCMV), Varicella-Zoster Virus (VZV) and Herpes Simplex Virus (HSV) were evaluated in vitro. RESULTS: Some compounds present antiviral activity. Compounds 5s and 5t are potent against both HCMV and VZV. Compounds 5m, 5n, 5s, and 5t show similar EC50 values against both TK+ and TK- VZV strains. CONCLUSION: 5-(Benzylamino)-1H-1, 2,3-triazole-4-carboxamides are active against herpesviruses and their activity is remarkably affected by the nature and the position of substituents in the benzene ring. The results indicate that these derivatives are independent of the viral thymidine kinase (TK) for activation, which is indispensable for current drugs. Their mechanisms of action may differ from those of the clinic anti-herpesvirus drugs.

Synthesis and Ativiral Activity of 5-(Benzylthio)-4-carbamyl-1,2,3-triazoles Against Human Cytomegalovirus (CMV) and Varicella-zoster Virus (VZV).

BACKGROUND: All of the clinical drugs for herpesvirus infections exhibit high toxicity and suffer from significant drug-resistantance. There is a great need for the development of new, effective, and safe anti-herpesvirus agents with different mechanisms of action. METHODS: A series of novel 5-(benzylthio)-1H-1,2,3-triazole-4-carboxamides were efficiently synthesized and EC50 values against human cytomegalovirus (HCMV), varicella-zoster virus (VZV) and herpes simplex virus (HSV) were evaluated in vitro. RESULTS: Some compounds possess antiviral activity. Compound 7f exhibits promising inhibitory activity against both HCMV and VZV. Our results also indicate that these derivatives are independent of the viral thymidine kinase (TK) for activation, which is indispensable for current drugs. CONCLUSION: 4,5-Bissubstiuted triazoles are active against herpesviruses and the nature and the position of substituents in the benzene ring remarkably affect their activity, such as bromo, cyano and cyanovynil substituents. Future studies should be undertaken to investigate the mechanism of action of these compounds.

Synthesis and Bioactivity of Novel Trisubstituted Triazole Nucleosides.

A series of novel trisubstituted 1,2,3-triazole purine nucleosides were efficiently synthesized via Huisgen 1,3-dipolar cycloaddition in good yields. Bioactivity against cytomegalovirus (CMV) and varicella-zoster virus (VZV) in human embryonic lung cell cultures was evaluated and all compounds show low antiviral activity.

Synthesis and antitumor activity of novel 2',3'-diethanethio-2',3',5'-trideoxy-5'-triazolonucleoside analogues.

A series of novel 2',3'-diethanethio-2',3',5'-trideoxy-5'-triazoloribonucleosides was synthesized in excellent yields and their antitumor activity was evaluated. These nucleoside analogues with aromatic substituted triazole rings showed significantly improved activity towards a broad range of tumor cell lines and those without arene substitutes were inactive.

A mild, efficient, and selective procedure for transprotection of acetonides to acetates catalyzed with HClO4-SiO2.

The transformation of acetonides into acetates is frequently required in synthetic chemistry. An efficient procedure for direct conversion of acetonides into acetates in the presence of HClO(4)-SiO(2) under mild conditions was developed. The acetonides of primary hydroxy groups are directly converted to diacetates, and the anomeric acetonides of furanosides are stereoselectively transformed into the corresponding acetyl beta-d-furanosides with a 2-acetoxyisopropyl group.