Identification, synthesis and quantification of eutylone consumption markers in a chemsex context.

Eutylone is a cathinone-derived synthetic amphetamine scheduled by the World Health Organization and European Monitoring Centre for Drugs and Drug Addiction since 2022 due to its growing consumption. We report here an eutylone intoxication involving a 38-year-old man and a 29-year-old woman in a chemsex context. A bag containing a white crystalline powder labelled as a research product was found in their vehicle. Nuclear magnetic resonance and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analyses identified the powder as eutylone and confirmed purity superior to 99%. LC-HRMS data analysis using molecular networking allowed to propose new eutylone metabolites in blood samples in a graphical manner. We described 16 phase I (e.g. hydroxylated or demethylated) and phase II metabolites (glucuroconjugates and sulfoconjugates). The same metabolites were found both in male and female blood samples. Toxicological analyses measured eutylone concentration in blood samples at 1374 ng/mL and 1536 ng/mL for the man and the woman, respectively. A keto-reduced metabolite (m/z 238.144) was synthesized to permit its quantification at 67 ng/mL and 54 ng/mL in male and female blood samples, respectively. Overall, the identification of these metabolites will increase the knowledge of potential drug consumption markers and allow to implement mass spectrometry databases to better monitor future drug abuse or consumption.

Chemistry and biology of ent-morphinan alkaloids.

Morphinan alkaloids have attracted constant attention since the isolation of morphine by Sertürner in 1805. However, a group of 45 compounds possessing a complete ent-morphinan backbone can also be found in the literature. These compounds are related to the morphinandienone subgroup and display a substitution pattern which is different from the morphinans. In particular, these alkaloids could be substituted at position C-2 and C-8 either by a hydroxy function or a methoxy moiety. Four groups of ent-morphinan alkaloids can be proposed, the salutaridine, pallidine, cephasugine and erromangine series. Interestingly, the botanical distribution of the ent-morphinans is more widespread than for the morphinans and includes the Annonaceae, Berberidaceae, Euphorbiaceae, Fumariaceae, Hernandiaceae, Lauraceae, Menispermaceae, Monimiaceae, Papaveraceae, and Ranunculaceae families. To date, their exact mode of production remains elusive and their interplay with the biosynthetic pathway of other classes of benzyltetrahydroisoquinoline alkaloids, in particular aporphines, should be confirmed. Exploration of the biological and therapeutic potential of these compounds is limited to some areas, namely central nervous system (CNS), inflammation, cancer, malaria and viruses. Further studies should be conducted to identify the cellular/molecular targets in view of promoting these compounds as new scaffolds in medicinal chemistry.

Strategies to access the [5-8] bicyclic core encountered in the sesquiterpene, diterpene and sesterterpene series.

Terpene compounds probably represent the most diversified class of secondary metabolites. Some classes of terpenes, mainly diterpenes (C20) and sesterterpenes (C25) and to a lesser extent sesquiterpenes (C15), share a common bicyclo[3.6.0]undecane core which is characterized by the presence of a cyclooctane ring fused to a cyclopentane ring, i.e., a [5-8] bicyclic ring system. This review focuses on the different strategies elaborated to construct this [5-8] bicyclic ring system and their application in the total synthesis of terpenes over the last two decades. The overall approaches involve the construction of the 8-membered ring from an appropriate cyclopentane precursor. The proposed strategies include metathesis, Nozaki-Hiyama-Kishi (NHK) cyclization, Pd-mediated cyclization, radical cyclization, Pauson-Khand reaction, Lewis acid-promoted cyclization, rearrangement, cycloaddition and biocatalysis.

Potent Antiplasmodial Derivatives of Dextromethorphan Reveal the Ent-Morphinan Pharmacophore of Tazopsine-Type Alkaloids.

The alkaloid tazopsine 1 was introduced in the late 2000s as a novel antiplasmodial hit compound active against Plasmodium falciparum hepatic stages, with the potential to develop prophylactic drugs based on this novel chemical scaffold. However, the structural determinants of tazopsine 1 bioactivity, together with the exact definition of the pharmacophore, remained elusive, impeding further development. We found that the antitussive drug dextromethorphan (DXM) 3, although lacking the complex pattern of stereospecific functionalization of the natural hit, was harboring significant antiplasmodial activity in vitro despite suboptimal prophylactic activity in a murine model of malaria, precluding its direct repurposing against the disease. The targeted N-alkylation of nor-DXM 15 produced a small library of analogues with greatly improved activity over DXM 3 against P. falciparum asexual stages. Amongst these, N-2'-pyrrolylmethyl-nor-DXM 16i showed a 2- to 36-fold superior inhibitory potency compared to tazopsine 1 and DXM 3 against P. falciparum liver and blood stages, with respectively 760 ± 130 nM and 2.1 ± 0.4 µM IC50 values, as well as liver/blood phase selectivity of 2.8. Furthermore, cpd. 16i showed a 5- to 8-fold increase in activity relative to DXM 3 against P. falciparum stages I-II and V gametocytes, with 18.5 µM and 13.2 µM IC50 values, respectively. Cpd. 16i can thus be considered a promising novel hit compound against malaria in the ent-morphinan series with putative pan cycle activity, paving the way for further therapeutic development (e.g., investigation of its prophylactic activity in vivo).

Structure simplification of the Securinine skeleton reveals the importance of BCD ring system for the cytotoxic activity on HCT116 and HL60 cell lines.

Function-oriented molecular editing of the polycyclic scaffold of securinine led to the preparation of a library of simplified analogs that have been evaluated for their cytotoxicity potential against HCT116 and HL60 human cell lines. Chemical diversity at the C14 position (securinine numbering) was generated through the site-selective γ-iodination followed by Pd-catalyzed Sonogashira and Suzuki-Miyaura reactions. To explain the selectivity in the iodination step, a reaction mechanism has been proposed. Surprisingly, the piperidine ring (ring A) of the securinine skeleton has been found to be irrelevant for the cytotoxic activity. Based on this finding, the pharmacophoric core of securinine could be simplified to the key BCD motif. The nature of the substituent at the nitrogen can vary from a methyl or an isobutyl group to a benzyl or a carbamate moiety. Interestingly, the N-benzyl substituted simplified analog exhibited the same cytotoxic activity as the parent compound securinine. This functional group tolerance paves the way for the installation of reactive handles for the synthesis of molecular probes for target identification.

Functional Characterization of the GATA-Type Transcription Factor PaNsdD in the Filamentous Fungus Podospora anserina and Its Interplay with the Sterigmatocystin Pathway.

The model ascomycete Podospora anserina, distinguished by its strict sexual development, is a prolific but yet unexploited reservoir of natural products. The GATA-type transcription factor NsdD has been characterized by the role in balancing asexual and sexual reproduction and governing secondary metabolism in filamentous fungi. In the present study, we functionally investigated the NsdD ortholog PaNsdD in P. anserina. Compared to the wild-type strain, vegetative growth, ageing processes, sexual reproduction, stress tolerance, and interspecific confrontations in the mutant were drastically impaired, owing to the loss of function of PaNsdD. In addition, the production of 3-acetyl-4-methylpyrrole, a new metabolite identified in P. anserina in this study, was significantly inhibited in the ΔPaNsdD mutant. We also demonstrated the interplay of PaNsdD with the sterigmatocystin biosynthetic gene pathway, especially as the deletion of PaNsdD triggered the enhanced red-pink pigment biosynthesis that occurs only in the presence of the core polyketide synthase-encoding gene PaStcA of the sterigmatocystin pathway. Taken together, these results contribute to a better understanding of the global regulation mediated by PaNsdD in P. anserina, especially with regard to its unexpected involvement in the fungal ageing process and its interplay with the sterigmatocystin pathway. IMPORTANCE Fungal transcription factors play an essential role in coordinating multiple physiological processes. However, little is known about the functional characterization of transcription factors in the filamentous fungus Podospora anserina. In this study, a GATA-type regulator PaNsdD was investigated in P. anserina. The results showed that PaNsdD was a key factor that can control the fungal ageing process, vegetative growth, pigmentation, stress response, and interspecific confrontations and positively regulate the production of 3-acetyl-4-methylpyrrole. Meanwhile, a molecular interaction was implied between PaNsdD and the sterigmatocystin pathway. Overall, loss of function of PaNsdD seems to be highly disadvantageous for P. anserina, which relies on pure sexual reproduction in a limited life span. Therefore, PaNsdD is clearly indispensable for the survival and propagation of P. anserina in its complex ecological niches.

Complementary Strategies to Unlock Biosynthesis Gene Clusters Encoding Secondary Metabolites in the Filamentous Fungus Podospora anserina.

The coprophilous ascomycete Podospora anserina is known to have a high potential to synthesize a wide array of secondary metabolites (SMs). However, to date, the characterization of SMs in this species, as in other filamentous fungal species, is far less than expected by the functional prediction through genome mining, likely due to the inactivity of most SMs biosynthesis gene clusters (BGCs) under standard conditions. In this work, our main objective was to compare the global strategies usually used to deregulate SM gene clusters in P. anserina, including the variation of culture conditions and the modification of the chromatin state either by genetic manipulation or by chemical treatment, and to show the complementarity of the approaches between them. In this way, we showed that the metabolomics-driven comparative analysis unveils the unexpected diversity of metabolic changes in P. anserina and that the integrated strategies have a mutual complementary effect on the expression of the fungal metabolome. Then, our results demonstrate that metabolite production is significantly influenced by varied cultivation states and epigenetic modifications. We believe that the strategy described in this study will facilitate the discovery of fungal metabolites of interest and will improve the ability to prioritize the production of specific fungal SMs with an optimized treatment.

Functional characterization of the sterigmatocystin secondary metabolite gene cluster in the filamentous fungus Podospora anserina: involvement in oxidative stress response, sexual development, pigmentation and interspecific competitions.

Filamentous fungi are known as prolific untapped reservoirs of diverse secondary metabolites, where genes required for their synthesis are organized in clusters. The bioactive properties of these compounds are closely related to their functions in fungal biology, which are not well understood. In this study, we focused on the Podospora anserina gene cluster responsible for the biosynthesis of sterigmatocystin (ST). Deletion of the PaStcA gene encoding the polyketide synthase and overexpression (OE) of the PaAflR gene encoding the ST-specific transcription factor in P. anserina were performed. We showed that growth of PaStcAΔ was inhibited in the presence of methylglyoxal, while OE-PaAflR showed a little inhibition, indicating that ST production may enhance oxidative stress tolerance in P. anserina. We also showed that the OE-PaAflR strain displayed an overpigmented thallus mediated by the melanin pathway. Overexpression of PaAflR also led to sterility. Interspecific confrontation assays showed that ST-overexpressed strains produced a high level of peroxides and possessed a higher competitiveness against other fungi. Comparative metabolite profiling demonstrated that PaStcAΔ strain was unable to produce ST, while OE-PaAflR displayed a ST overproduction. This study contributes to a better understanding of ST in P. anserina, especially with regard to its involvement in fungal physiology.

Viability of a [2 + 2 + 1] Hetero-Pauson-Khand Cycloaddition Strategy toward Securinega Alkaloids: Synthesis of the BCD-Ring Core of Securinine and Related Alkaloids.

Preliminary results related to the development of [2 + 2 + 1]-oxa-hetero-Pauson-Khand cycloaddition strategy toward the Securinega alkaloids are reported. The critical tricyclic BCD-ring core was assembled in only nine linear steps from cheap 4-hydroxy-l-proline. The study provides valuable insight into the scope of a rare hetero-Pauson-Khand reaction, a powerful tool for the rapid construction of butenolide-containing natural products.

The Securinega alkaloids.

Securinega alkaloids represent a family of plant secondary metabolites known for 50 years. Securinine (1), the most abundant and studied alkaloid of this series was isolated by Russian researchers in 1956. In the following years, French and Japanese scientists reported other Securinega compounds and extensive work was done to elucidate their intriguing structures. The homogeneity of this family relies mainly on its tetracyclic chemical backbone, which features a butenolide moiety (cycle D) and an azabicyclo[3.2.1]octane ring system (rings B and C). Interestingly, after a period of latency of 20 years, the Securinega topic reemerged as a prolific source of new natural structures and to date more than 50 compounds have been identified and characterized. The oligomeric subgroup gathering dimeric, trimeric, and tetrameric units is of particular interest. The unprecedented structure of the Securinega alkaloids was the subject of extensive synthetic efforts culminating in several efficient and elegant total syntheses. The botanical distribution of these alkaloids seems limited to the Securinega, Flueggea, Margaritaria, and Breynia genera (Phyllanthaceae). However, only a limited number of plant species have been considered for their alkaloid contents, and additional phytochemical as well as genetic studies are needed. Concerning the biosynthesis, experiments carried out with radiolabelled aminoacids allowed to identify lysine and tyrosine as the precursors of the piperidine ring A and the CD rings of securinine (1), respectively. Besides, plausible biosynthetic pathways were proposed for virosaine A (38) and B (39), flueggine A (46), and also the different oligomers flueggenine A-D (48-51), fluevirosinine A (56), and flueggedine (20). The case of nirurine (45) and secu'amamine (37) remains elusive and additional studies seem necessary to understand their mode of production. The scope of biological of activities of the Securinega alkaloids was mainly centered on the CNS activity of securinine (1), although the exact mechanism of action remained in part unknown. Nevertheless, for its stimulant and antispasmodic effects securinine nitrate was marketed as a drug in the USSR until the early 1990s. Moreover, securinine (1) and several other Securinega alkaloids recently demonstrated promising anticancer properties. In particular securinine (1) demonstrated markedly benefits in the treatment of acute myeloid leukemia.

Chiroptical study and absolute configuration of securinine oxidation products.

Time-dependant density functional theory-electronic circular dichroism spectra prediction was carried out to study the absolute configuration of phyllanthidine-type derivatives 5 and 6, derived from securinine (1) and its enantiomer virosecurinine (2), respectively. This method demonstrated to be very reliable in this alkaloid series. Thus, 5 and 6 shared the same stereochemistry as their parent precursors, confirming the retentive nature of the oxidation sequence. In addition, this study highlighted the key role of the methylene bridge (BC ring) in the chiroptical activity of these compounds. These results fully clarified the stereochemical relationships between the phyllanthidine and the securinine subgroups.

The isolation and synthesis of neodolastane diterpenoids.

The neodolastane diterpenoids comprise a group of 44 compounds including guanacastepenes, heptemerones, plicatilisins, radianspenes, 2,15-epoxy-5,13-dihydroxyneodolast-3-en-14-one and sphaerostanol. These fungal and marine natural products are characterized by a tricyclic neodolastane skeleton that consists of fused five-, seven- and six-membered rings. Their reported antibiotic activities against antibiotic-resistant bacteria together with strong antifungal and anticancer activities and their novel structures render these compounds interesting synthetic targets. The aim of this account is to summarise the progress in the isolation, characterisation and synthesis of these diterpenoids as well as to review their biogenetic origins and diverse biological activities since their discovery in 2000.

Tetra-hydro-alstonine.

In the title compound, C21H24N2O3 [systematic name: methyl (20α)-16,17-dide-hydro-19α-methyl-18-oxayohimban-16-carb-oxy-l-ate], the mol-ecule adopts an L-type conformation. The crystal packing is governed by one N-H⋯π and one C-H⋯π inter-actions. The crystal cohesion is ensured by inter-molecular van der Waals contacts [shortest O⋯O contact = 3.199 (2) Å].

Solvent/base effects in the selective domino synthesis of phenanthridinones that involves high-valent palladium species: experimental and theoretical studies.

The domino reaction of o-bromobenzamides 1a-m in the presence of K(2)CO(3) and the [PdCl(2)(PPh(3))(2)] catalyst granted a selective access to phenanthridinones 2 or to the new 1-carboxamide phenanthridinones 3 depending on the solvent, DMF or 1,4-dioxane, respectively. Investigations of the reaction parameters provided the first example of a direct correlation between the base dissociation and the solvent polarity on the selectivity observed. Moreover, mechanistic studies (NMR spectroscopy and ESI-MS monitoring) allowed us to characterize Pd(II) palladacycle 4 and biaryl species as common intermediates for these two domino processes. On that basis, C(sp(2))-C(sp(2)) bond formation is envisaged by generation of a Pd(IV) complex after oxidative addition of 1 into Pd(II) palladacycle 4, a rationale that is supported by DFT calculations. A general catalytic cycle is proposed to account for these observations.

Synthesis and biological evaluation of N-substituted benzo[c]phenanthrolines and benzo[c]phenanthrolinones as antiproliferative agents.

Benzo[c]phenanthrolines and benzo[c]phenanthrolinones substituted by dialkylaminoalkyl side chains at position N5 and C6, respectively, were synthesised and their biological activity evaluated. They displayed interessant cytotoxicity associated with some DNA interactions. However, the low topoisomerase 1 affinity suggests that other cellular targets are responsible for the antiproliferative activity.

Synthesis and biological evaluation of dialkylaminoalkylamino benzo[c][1,7] and [1,8]phenanthrolines as antiproliferative agents.

Benzo[c][1,7] and [1,8]phenanthroline substituted by dialkylaminoalkyl side chains at position C2 and C1, respectively, were synthesized and their biological activity evaluated. These compounds displayed more potent cytotoxicity toward L1210 cells than the parent unsubstituted compounds, associated with strong DNA interaction. The moderate TopoI inhibitory activity induced by the novel compounds suggests that other cellular targets should be responsible for the antiproliferative activity.

Selective unusual Pd-mediated biaryl coupling reactions: solvent effects with carbonate bases.

A one-step Pd-catalyzed reaction performed on an o-bromobenzamide permitted the selective formation of either phenanthridinones 2 via an ipso substitution or new phenanthridinone-1-carboxamides 3 through a direct N-arylation. A direct correlation between the solvent polarity and the carbonate base on the selectivity has been observed. The proposed catalytic cycle involves the initial formation of a common intermediate and depends on the base assistance.

Total syntheses of amphidinolides B1, B4, G1, H1 and structure revision of amphidinolide H2.

Nature is a pretty unselective "chemist" when it comes to making the highly cytotoxic amphidinolide macrolides of the B/G/H series. To date, 16 different such compounds have been isolated, all of which could now be approached by a highly convergent and largely catalysis-based route (see figure). This notion is exemplified by the total synthesis of five prototype members of this family.Dinoflagellates of the genus Amphidinium produce a "library" of closely related secondary metabolites of mixed polyketide origin, which are extremely scarce but highly promising owing to the exceptional cytotoxicity against various cancer cell lines. Because of the dense array of sensitive functionalities on their largely conserved macrocyclic frame, however, these amphidinolides of the B, D, G and H types elapsed many previous attempts at their synthesis. Described herein is a robust, convergent and hence general blueprint which allowed not only to conquest five prototype members of these series, but also holds the promise of making "non-natural" analogues available by diverted total synthesis. This notion transpires for a synthesis-driven structure revision of amphidinolide H2. The successful route hinges upon a highly productive Stille-Migita cross-coupling reaction at the congested and chemically labile 1,3-diene site present in all such targets, which required the development of a modified chloride- and fluoride-free protocol. The macrocyclic ring could be formed with high efficiency and selectivity by ring-closing metathesis (RCM) engaging a vinyl epoxide unit as one of the reaction partners. Because of the sensitivity of the targets to oxidizing and reducing conditions as well as to pH changes, the proper adjustment of the protecting group pattern for the peripheral -OH functions also constitutes a critical aspect, which has to converge to silyl groups only once the diene is in place. Tris(dimethylamino)sulfonium difluorotrimethylsilicate (TASF) turned out to be a sufficiently mild fluoride source to allow for the final deprotection without damaging the precious macrolides.

Total synthesis of discodermolide: optimization of the effective synthetic route.

An efficient and modulable total synthesis of discodermolide (DDM), a unique marine anticancer polyketide is described including related alternative synthetic approaches. Particularly notable is the repeated application of a crotyltitanation reaction to yield homoallylic (Z)-O-ene-carbamate alcohols with excellent selectivity. Advantage was taken of this reaction not only for the stereocontrolled building of the syn-anti methyl-hydroxy-methyl triads of DDM, but also for the direct construction of the terminal (Z)-diene. Of particular interest is also the installation of the C13=C14 (Z)-double bond through a highly selective dyotropic rearrangement. The preparation of the middle C8-C14 fragment in two sequential stages and its coupling to the C1-C7 moiety was a real challenge and required careful optimization. Several synthetic routes were explored to allow high and reliable yields. Due to the flexibility and robust character of this approach, it might enable a systematic structural variation of DDM and, therefore, the elaboration and exploration of novel discodermolide structural analogues.