Synthesis of 2-Prenylated Alkoxylated Benzopyrans by Horner-Wadsworth-Emmons Olefination with PPARα/γ Agonist Activity

We have synthesized series of 2-prenylated benzopyrans as analogues of the natural polycerasoidol, a dual PPARα/γ agonist with anti-inflammatory effects. The prenylated side chain consists of five or nine carbons with an α-alkoxy-α,β-unsaturated ester moiety. Prenylation was introduced via the Grignard reaction, followed by Johnson-Claisen rearrangement, and the α-alkoxy-α,β-unsaturated ester moiety was introduced by the Horner-Wadsworth-Emmons reaction. Synthetic derivatives showed high efficacy to activate both hPPARα and hPPARγ as dual PPARα/γ agonists. These prenylated benzopyrans emerge as lead compounds potentially useful for preventing cardiometabolic diseases.

Biosynthesis of azaphilones: a review

Covering up to 2020 Azaphilones are fungal polyketide pigments bearing a highly oxygenated pyranoquinone bicyclic core; they are receiving a great deal of increasing research interest for their applications in the agroalimentary, dyeing, cosmetic, printing and pharmaceutical industries. Their biosynthetic pathways are not fully elucidated; however, thanks to recent genomic approaches combined with the increasing genome sequencing of fungi, some of these pathways have been recently unveiled. This is the first review on the biosynthesis of azaphilonoids adressed from a genomic point of view.

New antibacterial cadiolide analogues active against antibiotic-resistant strains

The synthesis of new cadiolide analogues was carried out using a one-pot multi component synthesis. The antibacterial activity of these molecules was evaluated on standard and antibiotic resistant bacterial strains chosen for their involvement in human health or in food-born poisoning. Four molecules have shown good activities with MICs of 2 μg/mL^-1. The introduction of an indole group or the conversion of the lactone into lactam have highlighted two new families of molecules with promising antibacterial activity. In addition, most of these active molecules are devoid of cytotoxic activity against keratinocyte cells.

A Straightforward Synthesis of N-Substituted Ureas from Primary Amides

A direct and convenient method for the preparation of N-substituted ureas is achieved by treating primary amides with phenyliodine diacetate (PIDA) in the presence of an ammonia source (NH3 or ammonium carbamate) in MeOH. The use of 2,2,2-trifluoroethanol (TFE) as the solvent increases the electrophilicity of the hypervalent iodine species and allows the synthesis of electron-poor carboxamides. This transformation involves a nucleophilic addition of ammonia on the isocyanate intermediate generated in situ by a Hofmann rearrangement of the starting amide.

Iodonitrene in Action: Direct Transformation of Amino Acids into Terminal Diazirines and 15N2-Diazirines and Their Application as Hyperpolarized Markers

A one-pot metal-free conversion of unprotected amino acids to terminal diazirines has been developed using phenyliodonium diacetate (PIDA) and ammonia. This PIDA-mediated transformation occurs via three consecutive reactions and involves an iodonitrene intermediate. This method is tolerant to most functional groups found on the lateral chain of amino acids, it is operationally simple, and it can be scaled up to provide multigram quantities of diazirine. Interestingly, we also demonstrated that this transformation could be applied to dipeptides without racemization. Furthermore, ¹⁴N₂ and ¹⁵N₂ isotopomers can be obtained, emphasizing a key trans-imination step when using ¹⁵NH₃. In addition, we report the first experimental observation of ¹⁴N/¹⁵N isotopomers directly creating an asymmetric carbon. Finally, the ¹⁵N₂-diazirine from l-tyrosine was hyperpolarized by a parahydrogen-based method (SABRE-SHEATH), demonstrating the products' utility as hyperpolarized molecular tag.

Two-Photon Absorption and Cell Imaging of Fluorene-Functionalized Epicocconone Analogues

Epicocconone 1 is a natural chromophore isolated from the fungus Epicoccum nigrum that has shown applications in proteomics and fluorescent microscopy thanks to its unique pro-fluorescence properties. The modification of the skeleton of the natural product by replacing the triene side chain by a fluorenyl scaffold can noticeably increase the fluorophore's absorption coefficient. The synthesis of the analogues of the natural product has been made possible by the use of a palladium-catalyzed carbonylation reaction, allowing the construction of the β-keto-dioxinone key intermediate. Two-photon absorption cross-section measurements of the fluorenyl epicocconone analogues show a structure dependency with values ranging from 60 to 280 GM and live cell imaging show intense staining of intracellular vesicle-like structures around the nucleus.

Polycerasoidol, a Natural Prenylated Benzopyran with a Dual PPARα/PPARγ Agonist Activity and Anti-inflammatory Effect

Dual peroxisome proliferator-activated receptor-α/γ (PPARα/γ) agonists regulate both lipid and glucose homeostasis under different metabolic conditions and can exert anti-inflammatory activity. We investigated the potential dual PPARα/γ agonism of prenylated benzopyrans polycerasoidol (1) and polycerasoidin (2) and their derivatives for novel drug development. Nine semisynthetic derivatives were prepared from the natural polycerasoidol (1) and polycerasoidin (2), which were evaluated for PPARα, -γ, -δ and retinoid X receptor-α activity in transactivation assays. Polycerasoidol (1) exhibited potent dual PPARα/γ agonism and low cytotoxicity. Structure-activity relationship studies revealed that a free phenol group at C-6 and a carboxylic acid at C-9' were key features for dual PPARα/γ agonism activity. Molecular modeling indicated the relevance of these groups for optimal ligand binding to the PPARα and PPARγ domains. In addition, polycerasoidol (1) exhibited a potent anti-inflammatory effect by inhibiting mononuclear leukocyte adhesion to the dysfunctional endothelium in a concentration-dependent manner via RXRα/PPARγ interactions. Therefore, polycerasoidol (1) can be considered a hit-to-lead molecule for the further development of novel dual PPARα/γ agonists capable of preventing cardiovascular events associated with metabolic disorders.

Late-Stage Sulfoximination: Improved Synthesis of the Anticancer Drug Candidate Atuveciclib

An efficient synthesis of racemic atuveciclib was accomplished in five steps with an excellent 51% overall yield, using cheap reagents and mild reaction conditions. The key sulfoximination reaction was realized during the last step of the synthesis from the corresponding sulfide.

An optimized procedure for direct access to 1H-indazole-3-carboxaldehyde derivatives by nitrosation of indoles

The nitrosation of indoles under slightly acidic conditions and reverse addition conditions leads to the preparation of the corresponding indazole-3-carboxaldehydes in high yields and greatly minimizes side reactions.

Thermolysis of 1,3-dioxin-4-ones: fast generation of kinetic data using in-line analysis under flow

Rapid acquisition of kinetic data for thermolysis of 1,3-dioxin-4-ones is demonstrated with a commercial meso-scale flow reactor, using a step-change in flow rate or ‘push-out’ from the flow line.

Synthesis of pyrido[2,1-a]isoquinolin-4-ones and oxazino[2,3-a]isoquinolin-4-ones: new inhibitors of mitochondrial respiratory chain

Benzo[a]quinolizine is an important heterocyclic framework that can be found in numerous bioactive compounds. The general scheme for the synthesis of these compounds was based on the preparation of the appropriate dihydroisoquinolines by Bischler-Napieralski cyclization with good yields, followed by the Pemberton method to form the oxazinones or pyridones derivatives via acyl-ketene imine cyclocondensation. All the synthesized compounds were assayed in vitro for their ability to inhibit mitochondrial respiratory chain. Most of the tested compounds were able to inhibit the integrated electron transfer chain, measured as NADH oxidation, which includes complexes I, III and IV, in the low micromolar range. Oxazino[2,3-a]isoquinolin-4-ones displayed greater activity than their pyrido[2,1-a]isoquinolin-4-ones analogs. Indeed, the presence of a furan ring in C₂ position of oxazino[2,3-a]isoquinolin-4-ones provided the compound (1g) with the most potent biological activity. Therefore, these compounds and especially the oxazinone derivatives are in the tendency of the new less toxic antitumor agents that target mitochondrial electron transport chain in a middle range potency.

Facile and rapid access to linear and truncated microcystin analogues for the implementation of immunoassays

A series of simplified microcystin-LR analogues based on Adda [(2S,3S,8S,9S,4E,6E)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldecadienoic acid] or its corresponding aldol precursor linked to a polypeptide moiety have been synthesised and assessed for their binding affinity by the monoclonal antibody mAb MC159, an anti-microcystin-LR mAb recently selected by us for the detection of microcystins through various immunoassay formats. Some modifications have been brought to the enantiospecific synthesis of N-Boc-Adda developed by Pearson et al. (Org. Lett., 2000, 2, 2901) which enabled us to access in an economical and time-saving manner a small library of MC-LR linear analogues. Among which Adda was chosen to synthesise, as an illustrative example, a fluorescent probe derived from this beta-amino acid. This probe was subsequently solid-phase immobilised by means of oxime ligation in order to lead to biochips suitable for microcystin detection through the SPIT-FRI method.

Quinoline compounds decrease in vitro spontaneous proliferation of peripheral blood mononuclear cells (PBMC) from human T-cell lymphotropic virus (HTLV) type-1-infected patients

In vitro spontaneous proliferation is the immunological hallmark of peripheral blood mononuclear cells (PBMC) from HTLV-1-infected individuals. Quinoline compounds down regulate in vitro cell proliferation of HTLV-1 transformed cell lines. In the present study we assessed the capacity of quinolines to inhibit spontaneous cell proliferation of PBMC from HTLV-1-infected individuals. Twenty-two quinolines were evaluated. Toxicity was first assessed on PBMC from healthy donors by using both the Trypan blue technique and Tetrazolium Salt (XTT) method and then the antiproliferative effect was measured by a classic lymphoproliferative assay on PBMC from three HTLV-1-infected individuals, in the presence of decreasing concentrations of quinolines (from 100microM to 0.8microM), after 5 days of culture. We found that 14 out of 22 compounds were non-toxic to PBMC from uninfected individuals at 100, 50 and 10microM. Four compounds presented a capacity to inhibit more than 80% of the spontaneous proliferation: 7 at 25microM and 10, 20 and 23 at 100microM. Our results indicate that some quinolines block spontaneous proliferation of PBMC from HTLV-1-infected individuals.

In vitro and in vivo antileishmanial efficacy of a new nitrilquinoline against Leishmania donovani

The in vitro activity of a new analogue of 2-alkenylquinoline (2-nitrilquinoline or NQ) against Leishmania donovani was compared to oral reference drug miltefosine (HePC). IC(50) of NQ was found at 38.6 microM against promastigotes and 2.4 microM against intramacrophage amastigotes. In vivo evaluation in the L. donovani Balb/c mice model indicated that oral treatments at 12.5 and 25 mg/kg for 10 consecutive days significantly reduced the parasite burden in the liver by 68.9 and 68.5%, respectively. This activity was similar to those of HePC at 7.5 mg/kg for 10 days which reduced the parasite burden in liver by 72.5%. The present study shows the positive contribution of a nitril substitute being added into the alkenyl chain branched at the 2-position of the quinoline ring to the antileishmanial activity. In addition, any apparent toxicological disorder was observed during the experiments.

Acetogenins in Annona muricata L. (annonaceae) leaves are potent molluscicides

An ethanolic extract of the leaves of Annona muricata was shown to be toxic to adult forms of the snail Biomphalaria glabrata (LC50 9.32 microg mL(-1)) and to larvae of the brine shrimp Artemia salina (LC50 0.49 microg mL(-1)). Activity-guided fractionation of the extract gave rise to a sample with high molluscicidal activity that contained the acetogenins, annonacin (90%), isoannonacin (6%) and goniothalamicin (4%).

Efficacy of orally administered 2-substituted quinolines in experimental murine cutaneous and visceral leishmaniases

We report in this study the in vivo efficacy of nine 2-substituted quinolines on the Leishmania amazonensis cutaneous infection murine model and on the Leishmania infantum and Leishmania donovani visceral infection murine models. In the case of the L. amazonensis model, quinolines were administered orally at 25 mg/kg twice daily for 15 days. Quinolines 1, 2, 3, and 7 reduced by 80 to 90% the parasite burdens in the lesion, whereas N-methylglucamine antimoniate (Glucantime), administered by subcutaneous injections at 100 mg [28 mg Sb(V)] per kg of body weight daily, reduced the parasite burdens by 98%. In visceral leishmaniasis due to L. infantum, mice treated orally at 25 mg/kg daily for 10 days with quinolines 1, 4, 5, and 6 showed a significant reduction of parasite burdens in the liver and spleen. These quinolines were significantly more effective than meglumine antimoniate to reduce the parasite burden in both the liver and spleen. Also, the oral in vivo activity of three quinolines (quinolines 4, 5, and 2-n-propylquinoline) were determined against L. donovani (LV 9) at 12.5 and 25 mg/kg for 10 days. Their activity was compared with that of miltefosine at 7.5 mg/kg. Miltefosine, 2-n-propylquinoline, and quinoline 5 at 12.5 mg/kg significantly reduced the parasite burdens in the liver by 72, 66, and 61%, respectively. From the present study, quinoline 5 is the most promising compound against both cutaneous and visceral leishmaniasis. The double antileishmanial and antiviral activities of these compounds suggest that this series could be a potential treatment for coinfection of Leishmania-human immunodeficiency virus.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]

INTRODUCTION

Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3- substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9).

PATIENTS AND METHODS

The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-dimethylthiazol-2,5-diphényl)-tétrazolium bromide.

RESULTS

Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the enyne group had no influence in the antileishmanial activity.

CONCLUSION

Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference product, and to consider the use of these quinolines in the treament of the leishmaniasis.

Synthesis and antiprotozoal activity of some new synthetic substituted quinoxalines

A series of 29 new quinoxalines was synthesized and evaluated in vitro against several parasites (Leishmania donovani, Trypanosoma brucei brucei, and Trichomonas vaginalis). Several of them displayed interesting activities, and particularly four quinoxaline amides showed in vitro antileishmanial properties (IC50 less than 20 microM).

Nematocidal and trichomonacidal activities of 2-substituted quinolines

Several quinolines were synthesized and evaluated in vitro and in vivo against the nematodes Caenorhabditis elegans, Heligmosomoides polygyrus and the protozoa Trichomonas vaginalis. If some of them have shown in vitro nematocide activity (at 10 microM), however, their trichomonacidal activity reached 50% reduction at only 100 microM. The in vivo activity on Trichinella spiralis model was evaluated for some of the most in vitro active quinolines.

Biological evaluation of substituted quinolines

Several quinolines were synthesized and evaluated in vitro against several parasites (Trypanosoma brucei, T. cruzi, Leishmania infantum, L. amazonensis, Plasmodium falciparum). Then, they were evaluated in vitro (at 10 microM), against HTLV-1 transformed cells. A few of them displayed interesting activities, comparable to the reference drugs.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]

INTRODUCTION

Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3-substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9).

PATIENTS AND METHODS

The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-diméthylthiazol-2,5-diphényl)-tetrazolium bromide.

RESULTS

Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the e nyne group h ad no influence in the antileishmanial activity.

CONCLUSION

Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference p roduct, and to consider the use of these quinolines in the treament of the leishmaniasis.