4-Benzyloxy-γ-Sultone Derivatives: Discovery of a Novel Family of Non-Nucleoside Inhibitors of Human Cytomegalovirus and Varicella Zoster Virus

Novel pyridine-containing sultones: Structure-activity relationship and biological evaluation as selective AChE inhibitors for the treatment of Alzheimer's disease

Novel pyridine-containing sultones were synthesized and evaluated for their cholinesterase (ChE) inhibitory activity. Most of compounds showed selective acetylcholinesterase (AChE) inhibitory activity. The structure-activity relationship (SAR) showed: (i) the fused pyridine-containing sultones increase AChE inhibition, series B>series A; (ii) for series A, the effect of the 4-substituent on AChE activity, p->m- or o-; (iii) for series B, a halophenyl group increase activity. Compound B4 (4-(4-chlorophenyl)-2,2-dioxide-3,4,5,6-tetrahydro-1,2-oxathiino[5,6-h]quinoline) was identified as a selective AChE inhibitor (IC₅₀ =8.93 μM), and molecular docking studies revealed a good fit into TcAChE via hydrogen interactions between the δ-pyridylsultone scaffold with Asp72, Ser122, Phe288, Phe290 and Trp84. Compound B4 showed reversible and non-competitive (K_i =7.67 μM) AChE inhibition, nontoxicity and neuroprotective activity. In vivo studies confirmed that compound B4 could ameliorate the cognitive performance of scopolamine-treated C57BL/6 J mice, suggesting a significant benefit of AChE inhibition for a disease-modifying treatment of AD.

Synthesis of Sultones from Chlorosulfates by a Complex Cascade Reaction Occurring under Mild Thermal Conditions

Chlorosulfate derivatives are interesting reagents that have been traditionally used to get other sulfur-containing compounds by formal nucleophilic substitution of the chlorine atom. This work describes a different mode of reactivity of alkyne-containing chlorosulfates to get sultones, the sulfur analogues of lactones. The complex skeletal rearrangement observed in this transformation is comparable to those intricate processes promoted or catalyzed by organometallic compounds. However, the reaction here described does not require any reagent or additive, being just a thermal process. Computational calculations support a mechanism based on a series of cascade reactions where almost every step is counterintuitive. Some of these steps include original processes related to classical reactions, thus adding complementary views to traditional organic chemistry.

Progress in the synthesis of δ-sultones

Abstract

Sultones, the cyclic esters of hydroxyl sulfonic acids, are a fascinating class of heterocycles and the recent years have witnessed an increasing interest in these molecules, especially in six-ring δ-sultones. The importance of these compounds is either because of their biological properties themselves or due to their versatility as intermediates in more complex target syntheses. Accordingly, the development of new synthesis methods to access δ-sultones is an important and rewarding task which we wish to highlight in this review.

Graphical abstract

A portal to a class of novel sultone-functionalized pyridines via an annulative SuFEx process employing earth abundant nickel catalysts

An efficient Ni²⁺ promoted process for the synthesis of a class of structurally unique heterocycles containing both pyridines and sultones was developed through a SuFEx annulation. This protocol serves as an irreplaceable asset for medicinal chemistry and drug discovery.

Identification of an indol-based derivative as potent and selective varicella zoster virus (VZV) inhibitor

We report the synthesis and antiviral activity of a new family of non-nucleoside antivirals, derived from the indole nucleus. Modifications of this template through Mannich and Friedel-Crafts reactions, coupled with nucleophilic displacement and reductive aminations led to 23 final derivatives, which were pharmacologically tested. Tryptamine derivative 17a was found to have a selective inhibitory activity against human varicella zoster virus (VZV) replication in vitro, being inactive against a variety of other DNA and RNA viruses. A structure-activity relationship (SAR) study showed that the presence of a biphenyl ethyl moiety and the acetylation at the amino group of tryptamine are a prerequisite for anti-VZV activity. The novel compound shows the same activity against thymidine kinase (TK)-competent (TK⁺) and TK-deficient (TK⁻) VZV strains, pointing to a novel mechanism of antiviral action.

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A library of indole-based derivatives has been designed and synthesized as potential antiviral agents.

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Friedel-Crafts and Mannich reactions were used for the synthesis of different indole derivatives.

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Tryptamine derivative 17a displays significant inhibitory activity against VZV replication.

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A mechanism of action independent from the virus-encoded thymidine kinase is suggested.

Sultones and Sultines via a Julia-Kocienski Reaction of Epoxides

The development of the homologous Julia–Kocienski reaction has led to the discovery of two new reaction modes of epoxides with sulfones. These pathways allow rapid and direct access to a range of γ-sultones and γ-sultines.

N-Heterocyclic Carbene Catalyzed Synthesis of δ-Sultones via α,β-Unsaturated Sulfonyl Azolium Intermediates

A limited array of reactive intermediates have enabled a wealth of discoveries in N-heterocyclic carbene organocatalysis. In this study, the viability of α,β-unsaturated sulfonyl azoliums as double electrophiles in new reactions is examined. Specifically, the (3+3) annulation of such species with the trimethylsilyl enol ethers of various 1,3-dicarbonyl compounds has been developed. This reaction provides access to a range of novel unsaturated δ-sultones (18 examples) in good yields (40-88 %) under mild reaction conditions. Mechanistic studies and the development of an enantioselective variant (55 % yield, 73:27 e.r.) support the intermediacy of an α,β-unsaturated sulfonyl azolium species.

New synthesis method for sultone derivatives: synthesis, crystal structure and biological evaluation of S-CA

There has been no remarkable progress in the synthesis of sultones in recent years. To facilitate more detailed studies of this functional group, we found a new method to synthesize the sulfonic acid lactone derivatives and finish its ring-closing reaction. A new sultone derivative, (E)-ethyl 4-oxo-6-styryl-3,4-dihydro-1,2-oxathiine-5-carboxylate 2,2-dioxide (S-CA), was synthesized and structurally identified by ¹H-NMR, ¹³C-NMR, HMQC and X-ray single crystal diffraction analysis. The new rapid synthesis extended the method of ring-closing reaction of sulfonic acid lactone derivatives. The angiogenesis activities of S-CA were evaluated by the chick chorioallantoic membrane (CAM) model. It could selectively suppress small angiogenesis in CAM, without influencing either middle and large angiogenesis. In addition, anticancer efficacy of S-CA was evaluated in vivo using a murine sarcoma S180 model. Reduction of the tumor weight and tumor HE staining regions demonstrated that S-CA (10 mg/kg, intraperitoneal injection) had potent inhibition effects and a 44.71% inhibitory rate in S180 mice. Moreover, an acute toxicity test showed that the LD₅₀ value of S-CA via intraperitoneal injection was 25.624 mg/kg.

Optimization of xanthatin extraction from Xanthium spinosum L. and its cytotoxic, anti-angiogenesis and antiviral properties

The aqueous extraction of the sesquiterpene lactone xanthatin from Xanthium spinosum L. favours the conversion of xanthinin (1) to xanthatin (2) via the loss of acetic acid. The cytotoxic (Hep-G2 and L1210 human cell lines) and antiviral activities of isolated xanthatin are established. This natural compound shows significant cytotoxicity against the Hep-G2 cell line and our experimental results reveal its strong anti-angiogenesis capacity in vitro. The structure of xanthatin is determined by spectroscopic methods and for the first time confirmed by X-ray diffraction.

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A method to maximize extraction of xanthatin is proposed.

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X-ray crystal of xanthatin is contributed by the first time and confirms the structure.

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Antitumor, antiviral and antiangiogenesis activities of xanthatin are performed.

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Xanthatin exhibited potent antiangiogenic activity.

Anti-herpesvirus agents: a patent and literature review (2003 to present)

INTRODUCTION

The standard therapy used to treat herpesvirus infections is based on the application of DNA polymerase inhibitors such as ganciclovir or aciclovir. Unfortunately, all of these compounds exhibit relatively high toxicity and the mutation of herpesviruses results in the appearance of new drug-resistant strains. Consequently, there is a great need for the development of new, effective and safe anti-herpesvirus agents that employ different patterns of therapeutic action at various stages of the virus life cycle.

AREAS COVERED

Patents and patent applications concerning the development of anti-herpesvirus agents displaying different mechanisms of action that have been published since 2003 are reviewed. In addition, major discoveries in this field that have been published in academic papers have also been included.

EXPERT OPINION

Among all the anti-herpesvirus agents described in this article, the inhibitors of viral serine protease seem to present one of the most effective/promising therapeutics. Unfortunately, the practical application of these antiviral agents has not yet been proven in any clinical trials. Nevertheless, the dynamic and extensive work on this subject gives hope that a new class of anti-herpesvirus agents aimed at the enzymatic activity of herpesvirus serine protease may be developed.

Synthesis and anti-BVDV activity of novel δ-sultones in vitro: implications for HCV therapies

In this study we report the synthesis and activity against bovine viral diarrhea virus (BVDV) of a novel series of bicycle δ-sultones containing γ-lactones. BVDV is responsible for major losses in cattle. Some of the synthesized δ-sultones showed pronounced anti-BVDV activity with EC50 values of 0.12-1.0μM and no significant cytotoxicity. Among them, the ortho bromosubstituted derivative 4f (EC50=0.12μM) showed better antiviral activity than other derivatives and was 10 fold more that of than positive control ribavirin (EC50=1.3μM). BVDV is also considered to be a valuable surrogate for the hepatitis C virus (HCV) in antiviral drug studies. The above results provided a novel candidate for the development of anti-HCV agents.

Synthesis and SAR studies on azetidine-containing dipeptides as HCMV inhibitors

SAR studies on an azetidine-containing dipeptide prototype inhibitor of HCMV are described. Three series of structurally modified analogues, involving substitutions at the N- and C-terminus, and at the C-terminal side-chain were synthesized and evaluated for antiviral activity. Aliphatic or no substituents at the C-carboxamide group, an aliphatic C-terminal side-chain, as well as a benzyloxycarbonyl moiety at the N-terminus were absolute requirements for anti-HCMV activity. The conformational restriction induced by the 2-azetidine residue into the dipeptide derivatives, identified by ¹H NMR as a γ-type reverse turn, seems to have influence on the activity of these molecules.