Synthesis and Anti-HIV Profile of a Novel Tetrahydroindazolylbenzamide Derivative Obtained by Oxazolone Chemistry

A new tetrahydroindazolylbenzamide derivative has been synthesized, characterized, and evaluated as HIV-inhibitor. The biological data revealed the ability to inhibit HIV proliferation with low cytotoxicity allowing for significant selectivity (EC₅₀ 2.77 μM; CC₅₀ 118.7 μM; SI = 68). The compound did not inhibit the viral integrase as demonstrated by in vitro studies. QPCR experiments showed that the block of viral replication occurred at early replication steps, prior to integration, profiling it as a late reverse transcription inhibitor. An efficient multistep strategy was adopted for the synthesis of the scaffold, consisting of a sequential ring-opening reaction of oxazol-5-(4H)-one with 1,3-diketone, followed by cyclocondensation with hydrazine and hydrolysis of the nitrile to the desired carboxamide.

Alterations in Red Blood Cell Functionality Induced by an Indole Scaffold Containing a Y-Iminodiketo Moiety: Potential Antiproliferative Conditions

We have recently proposed a new erythrocyte-based model of study to predict the antiproliferative effects of selected heterocyclic scaffolds. Starting from the metabolic similarity between erythrocytes and cancer cells, we have demonstrated how the metabolic derangement induced by an indolone-based compound (DPIT) could be related to its antiproliferative effects. In order to prove the validity of our biochemical approach, in the present study the effects on erythrocyte functionality of its chemical precursor (PID), whose synthesis we reported, were investigated. The influence of the tested compound on band 3 protein (B3), oxidative state, ATP efflux, caspase 3, metabolism, intracellular pH, and Ca²⁺ homeostasis has been evaluated. PID crosses the membrane localizing into the cytosol, increases anion exchange, induces direct caspase activation, shifts the erythrocytes towards an oxidative state, and releases less ATP than in normal conditions. Analysis of phosphatidylserine externalization shows that PID slightly induces apoptosis. Our findings indicate that, due to its unique features, erythrocyte responses to exogenous molecular stimuli can be fruitfully correlated at structurally more complex cells, such as cancer cells. Overall, our work indicates that erythrocyte is a powerful study tool to elucidate the biochemical/biological effects of selected heterocycles opening considerable perspectives in the field of drug discovery.

Electrical release of dopamine and levodopa mediated by amphiphilic β-cyclodextrins immobilized on polycrystalline gold

Vesicles of cationic amphiphilic β-cyclodextrins have been immobilized on polycrystalline gold by exploiting the chemical affinity between their amino groups and Au atoms. The presence of cyclodextrins has been widely investigated by means of AFM, XPS, kelvin probe and electrochemical measurements. This multi-functional coating confers distinct electrochemical features such as pH-dependent behavior and partial/total blocking properties towards electro-active species. The host-guest properties of β-cyclodextrins have been successfully exploited in order to trap drugs, like dopamine and levodopa. The further release of these drugs was successfully achieved by providing specific electrical stimuli. This proof-of-concept led us to fabricate an electronic device (i.e. an organic transistor) capable of dispensing both dopamine and levodopa in aqueous solution.

Efficient synthesis of highly substituted tetrahydroindazolone derivatives

A straightforward and efficient method for the synthesis of novel highly substituted and diversely functionalized indazolone derivatives has been developed. The transformation consists of a cyclocondensation of selected 1,3,3'-tricarbonyls with monosubstituted hydrazines. The starting β-triketones were prepared by an efficient chemo- and regioselective method under MW irradiation, exploiting the oxazolone chemistry. The reaction is easily accomplished under mild conditions and appears versatile, providing a synthetic diversification method with potential for drug-like compounds preparation.

Decorated 6,6′,7,7′-tetrahydro-1H,1′H-2,3′-biindole scaffold as promising candidate for recognition of the CDK2 allosteric site

Decorated 6,6′,7,7′-tetrahydro-1H,1′H-2,3′-biindoles, such as DPIT, targeting CDK2 seem to be an attractive scaffold for development of useful anticancer drugs.

A new erythrocyte-based biochemical approach to predict the antiproliferative effects of heterocyclic scaffolds: The case of indolone

BACKGROUND

The indole core is a key structural feature of many natural products and biomolecules with broad spectrum chemotherapeutic properties. Some of us have recently synthesized a library of biologically promising indolone-based compounds. The present study focuses on the effects of one of them, namely DPIT, on human erythrocytes.

METHODS

We have examined the influence of DPIT on band 3 protein, intracellular ATP concentration and transport, caspase 3 activation, metabolic adaptation and membrane stability.

RESULTS

Our study elucidates that DPIT, intercalated into the phospholipid bilayer, decreases the anion transport, the intracellular ATP concentration and the cytosolic pH, inducing a direct activation of caspase 3.

CONCLUSIONS

Starting from the metabolic similarity between erythrocytes and cancer cells, we investigate how the metabolic derangements and membrane alterations induced by selected heterocycles could be related to the antiproliferative effects.

GENERAL SIGNIFICANCE

Our work aims to propose a new model of study to predict the antiproliferative effects of heterocyclic scaffolds, pointing out that only one of the listed conditions would be unfavorable to the life cycle of neoplastic cells.

A porphyrin/β-cyclodextrin conjugated nano-system having a pan-lid molecular structure for smart drug carrier applications

In this study, 5,10,15-tri[p(9-methoxy-triethyleneoxy)phenyl]-20-[p-phenylisophthalate-β-cyclodextrin]porphyrin, a compound containing a porphyrin and a β-cyclodextrin unit covalently linked by means of an isophthalic bridge, was synthesized and characterized by NMR, MALDI-TOF mass spectrometry and UV-vis and circular dichroism spectroscopies. This porphyrin/β-cyclodextrin system, with the porphyrin unit connected to the lower rim (OH-2) of the cyclodextrin structure, is water-soluble and no evidence of a self-assembly arrangement between the porphyrin and cyclodextrin units appears. In this way, the β-cyclodextrin cavities remain free, retaining their potential ability of drug-delivery, with the spectroscopic advantage induced by the high absorbance of the porphyrin unit. Furthermore, the porphyrin unit, interacting with the guest and acting as a lid, could have a role in the controlled release process of the drug.

Direct synthesis of C3-mono-functionalized oxindoles from N-unprotected 2-oxindole and their antileishmanial activity

A novel approach for the synthesis of unprecedented C3-mono-functionalized indolin-2-ones is reported, starting from 2-oxindole and chalcones. The reactions proceed regioselectively under mild conditions, without di- and tri-alkylated side products. The new compounds have been evaluated in vitro for their antiproliferative effects against the protozoan Leishmania infantum. Interestingly, they appear able to kill L. infantum promastigotes and amastigotes, without significant cytotoxic effects.

Aldol-type compounds from water-soluble indole-3,4-diones: synthesis, kinetics, and antiviral properties

A straightforward transformation of indole-3,4-diones is reported. The reaction feasibility is evidenced by kinetic studies on a model substrate, revealing a double phase process with a first faster pseudo-first-order step (i.e., deprotonation of the dione and self-nucleophilic attack of the anion) and a subsequent slower dehydration of the intermediate. The overall process is faster at pH higher than the pK value of the investigated substrate. The biological relevance of new compounds has been assessed in vitro against herpes simplex virus type-1 (HSV-1), showing a more promising biological profile with respect to their precursors.

Self-catalyzed Mannich-type reaction of enolizable cyclic 1,3-dicarbonyls to acyclic nitrones: an entry to functionalized β-enamino diones

A new method for the preparation of highly functionalized β-enamino diones has been developed. The protocol involves an initial self-catalyzed Mannich-type reaction of enolizable cyclic 1,3-dicarbonyls to nitrones, followed by a spontaneous intramolecular reorganization of the resulting nonisolated hydroxylamine to enamino derivatives. These compounds retain the features of unnatural α-amino acids. The ease of preparation makes them attractive intermediates for the synthesis of peptidomimetics, polyheterocycles, and other multifunctional compounds. All experimental results have been efficiently rationalized by in silico studies at the M06-2X level of theory, and a valid mechanistic pathway has been proposed.

Diastereoselective multicomponent synthesis and anti-HSV-1 evaluation of dihydrofuran-fused derivatives

Enolizable 6-membered cyclic 1,3-dicarbonyls undergo an efficient and diastereoselective domino condensation/addition/heterocyclization reaction with arylaldehydes and phenacyl chloride, producing highly substituted dihydrofuran-fused derivatives. Ring size of the cyclic 1,3-dicarbonyls and the presence of at least one keto group are crucial to the reaction's success. The new compounds were evaluated in vitro for antiviral activity against herpes simplex virus type-1 (HSV-1). Interestingly, some of them appeared able to interfere with HSV-1 replication, without detection of cytotoxic effects.