From biomass-derived fructose to γ-valerolactone: Process design and techno-economic assessment.

This work proposes a process design and techno-economic assessment for the production of γ-valerolactone from lignocellulosic derived fructose at industrial scale, with the aim of exploring its feasibility, identifying potential obstacles, and suggesting improvements in the context of France. First, the conceptual process design is developed, the process modelled and optimized. Second, different potential scenarios for the energy supply to the process are analyzed by means of a set of economic key performance indicators, aimed at highlighting the best potential profitability scenario for the sustainable exploitation of waste biomass in the context analyzed. The lowest Minimum Selling Price for GVL is obtained at 10 kt/y plant fueled by biomass, i.e. 1.89 €/kg, along with the highest end-of-live revenue, i.e. 113 M€. Finally, a sensitivity and uncertainties analysis, based on Monte Carlo simulations, are carried out on the results in order to test their robustness with respect to key input parameters.

Absorption of cinnarizine from type II lipid-based formulations: Impact of lipid chain length, supersaturation, digestion, and precipitation inhibition.

Lipid-based formulations (LBFs) are an enabling-formulation approach for lipophilic poorly water-soluble compounds. In LBFs, drugs are commonly pre-dissolved in lipids, and/or surfactants/cosolvents, hereby avoiding the rate-limiting dissolution step. According to the Lipid formulation classification system, proposed by Pouton in 2006, in type II LBFs a surfactant with an HLB-value lower than 12 is added to the lipids. If high drug doses are required, e.g. for preclinical toxicity studies, supersaturated LBFs prepared at elevated temperatures may be a possibility to increase drug exposure. In the present study, the impact of digestion on drug absorption in rats was studied by pre-dosing of the lipase inhibitor orlistat. The lipid chain length of the type II LBFs was varied by administration of a medium-chain- (MC) and a long-chain (LC)-based formulation. Different drug doses, both non-supersaturated and supersaturated, were applied. Due to an inherent precipitation tendency of cinnarizine in supersaturated LBFs, the effect of the addition of the precipitation inhibitor Soluplus® was also investigated. The pharmacokinetic results were also evaluated by multiple linear regression. In most cases LC-based LBFs did not perform better in vivo, in terms of a higher area under the curve (AUC0-24 h) and maximal plasma concentration (Cmax), than MC-based LBFs. The administration of supersaturated LBFs resulted in increased AUC0-24 h (1.5 - 3.2-fold) and Cmax (1.1 - 2.6-fold)-values when compared to the non-supersaturated equivalents. Lipase inhibition led to a decreased drug exposure in most cases, especially for LC formulations (AUC0-24 h reduced to 47 - 67%, Cmax to 46 - 62%). The addition of Soluplus® showed a benefit to drug absorption from supersaturated type II LBFs (1.2 - 1.7-fold AUC0-24 h), due to an increased solubility of cinnarizine in the formulation. Upon dose-normalization of the pharmacokinetic parameters, no beneficial effect of Soluplus® could be demonstrated.

Structural effects of oxidation on sugars: glucose as a precursor of gluconolactone and glucuronolactone.

Although structural information on sugars is wide, experimental studies on the oxidation products of sugars in the gas phase, free from solvent interactions, have been rarely reported. We present an experimental work on the changes in the structure and interactions of two products of glucose oxidation (D-glucono-1,5-lactone (GlcL) and D-glucurono-6,3-lactone (GlcurL)) with respect to their precursor. Features such as intramolecular interactions, ring puckering and tautomerism were observed.

Structure-Activity Relationships of Natural C-9-Methyl-Substituted 10-Membered Lactones and Their Semisynthetic Derivatives.

Fungal 10-membered lactones (TMLs), such as stagonolide A, herbarumin I, pinolidoxin, and putaminoxin, are promising candidates for the development of nature-derived herbicides. The aim of this study was to analyze the structure-activity relationships (SAR) of C-9-methyl-substituted TMLs with a multitarget bioassay approach to reveal compounds with useful (phytotoxic, entomotoxic, antimicrobial) or undesirable (cytotoxic) bioactivities. A new TML, stagonolide L (1), along with five known compounds (stagonolides D (2) and E (3), curvulides A (4) and B1/B2 (5a,b), and pyrenolide C (6)), were purified from cultures of the phytopathogenic fungus Stagonospora cirsii, and five semisynthetic derivatives of 3 and 4 (7-11) were obtained. The absolute configuration of 4 was revised to 2Z, 4S, 5S, 6R, and 9R. The identity of 5a,b and stagonolide H is discussed. The phytotoxicity of compound 4, the entomotoxicity of 5a,b, and nonselective toxicity of compound 6 are demonstrated. The latter confirms the hypothesis that the α,ß-unsaturated carbonyl group is associated with the high general toxicity of TML, regardless of its position in the ring and other substituents. The epoxide in compound 4 is important for phytotoxicity. The revealed SAR patterns will be useful for further rational design of TML-based herbicides including curvulide A analogs with a 4,5-epoxy group.

Reaction Pattern and Mechanistic Aspects of Iodine and Iodine-Based Reagents in Selenylation of Aliphatic, Aromatic, and (Hetero)Cyclic Systems.

Organoselenium compounds have been the subject of extensive research since the discovery of the biologically active compound ebselen. Ebselen has recently been found to show activity against the main protease of the virus responsible for COVID-19. Other organoselenium compounds are also well-known for their diverse biological activities, with such compounds exhibiting interesting physical properties relevant to the fields of electronics, materials, and polymer chemistry. In addition, the incorporation of selenium into various organic molecules has garnered significant attention due to the potential of selenium to enhance the biological activity of these molecules, particularly in conjunction with bioactive heterocycles. Iodine and iodine-based reagents play a prominent role in the synthesis of organoselenium compounds, being valued for their cost-effectiveness, non-toxicity, and ease of handling. These reagents efficiently selenylate a broad range of organic substrates, encompassing alkenes, alkynes, and cyclic, aromatic, and heterocyclic molecules. They serve as catalysts, additives, inducers, and oxidizing agents, facilitating the introduction of different functional groups at alternate positions in the molecules, thereby allowing for regioselective and stereoselective approaches. Specific iodine reagents and their combinations can be tailored to follow the desired reaction pathways. Here, we present a comprehensive review of the progress in the selenylation of organic molecules using iodine reagents over the past decade, with a focus on reaction patterns, solvent effects, heating, microwave, and ultrasonic conditions. Detailed discussions on mechanistic aspects, such as electrophilic, nucleophilic, radical, electrochemical, and ring expansion reactions via selenylation, multiselenylation, and difunctionalization, are included. The review also highlights the formation of various cyclic, heterocyclic, and heteroarenes resulting from the in situ generation of selenium intermediates, encompassing cyclic ketones, cyclic ethers, cyclic lactones, selenophenes, chromones, pyrazolines, pyrrolidines, piperidines, indolines, oxazolines, isooxazolines, lactones, dihydrofurans, and isoxazolidines. To enhance the reader's interest, the review is structured into different sections covering the selenylation of aliphatic sp2/sp carbon and cyclic sp2 carbon, and then is further subdivided into various heterocyclic molecules.

Ergosterols with rare peroxide, oxetane ring moiety, and a lactone ring from Aspergillus spectabilis and their immunosuppressive activities.

Ten ergostane-type steroids, including seven undescribed ones named spectasteroids A-G, were obtained from Aspergillus spectabilis. Their structures and absolute configurations were determined based on HRESIMS, NMR, ECD calculations, and single-crystal X-ray diffraction analyses. Structurally, spectasteroid A was a unique example of aromatic ergostane-type steroid that featured a rare peroxide ring moiety; spectasteroid B contained a rare oxetane ring system formed between C-9 and C-14; and spectasteroid C was an unusual 3,4-seco-ergostane steroid with an extra lactone ring between C-3 and C-9. Spectasteroids F and G specifically showed inhibitory effects against concanavalin A-induced T lymphocyte proliferation and lipopolysaccharide-induced B lymphocyte proliferation, with IC50 values ranging from 2.33 to 4.22 µM. Spectasteroid F also showed excellent antimultidrug resistance activity, which remarkable enhanced the inhibitory activity of PTX on the colony formation of SW620/Ad300 cells.

Copper-catalysed dehydrogenation or lactonization of C(sp3)-H bonds.

Cytochrome P450 enzymes are known to catalyse bimodal oxidation of aliphatic acids via radical intermediates, which partition between pathways of hydroxylation and desaturation1,2. Developing analogous catalytic systems for remote C-H functionalization remains a significant challenge3-5. Here, we report the development of Cu(I)-catalysed bimodal dehydrogenation/lactonization reactions of synthetically common N-methoxyamides through radical abstractions of the γ-aliphatic C-H bonds. The feasibility of switching from dehydrogenation to lactonization is also demonstrated by altering reaction conditions. The use of a readily available amide as both radical precursor and internal oxidant allows for the development of redox-neutral C-H functionalization reactions with methanol as the sole side product. These C-H functionalization reactions using a Cu(I) catalyst with loading as low as 0.5 mol.% is applied to the diversification of a wide range of aliphatic acids including drug molecules and natural products. The exceptional compatibility of this catalytic system with a wide range of oxidatively sensitive functionality demonstrates the unique advantage of using a simple amide substrate as a mild internal oxidant.

Sesquiterpene Acids and Lactones from Inula Confertiflora with their Antibacterial Activities.

The phytochemical investigation of the leaves of Inula confertiflora, a medicinal plant endemic to Ethiopia, led to the isolation of 15 terpenoids; 1ß-hydroxy-α-costic acid (1), 3α-hydroxycostic acid (2), isotelekin (3), asperilin (4), carabrone (5), carpesioline (6), graveolide (7), inuviscolide (8), 8-epi-inuviscolide (9), 1ß,4ß-dihydroxy-5α(H)-guaia-10(14),11(13)-dien-8α,12-olide (10), isoinuviscolide (11), 4ß,10ß-dihydroxy-5α(H)-1,11(13)-guaidien-8α,12-olide (12), 4ß,10ß-dihydroxy-1ß(H)-5α(H)-guai-11(13)-en-8α,12-olide (13), 4ß,10α-dihydroxy-1ß(H)-5α(H)-guai-11(13)-en-8α,12-olide (14), 4ß,10α-dihydroxy-1α(H)-5α(H)-guai-11(13)-en-8α,12-olide (15). Herein, structural elucidation and full NMR data for compound 1 are presented for the first time. The structures were elucidated using NMR, HRESIMS, and by comparison with literature data. The relative configurations were defined by NOESY correlations and single-crystal X-ray crystallography. Herein, crystallography data of 6 and 7 were reported for the first time. The antibacterial efficacy of some of the isolated compounds was evaluated against two commonly dispersed environmental strains of Escherichia coli and Staphylococcus aureus. Compounds 1, 3, 6, 7, and 8 exhibited moderate antibacterial activities against the tested organisms. The chemotaxonomic significance of compounds is discussed.

Three rare anti-inflammatory sesquiterpene lactones from Magnolia grandiflora.

Four new sesquiterpene lactones (SLs) (1-4), along with a biosynthetically related SL (5), have been isolated from the leaves of Magnolia grandiflora. Magrandate A (1) is notable as the first C18 homogemarane type SL, featuring a unique 1,7-dioxaspiro[4.4]nonan-6-one core. Compounds 2 and 3, representing the first instances of chlorine-substituted gemarane-type SL analogs in natural products, were also identified. The structures of these isolates were elucidated through a combination of spectroscopic data analysis, electronic circular dichroism calculations, and X-ray single-crystal diffraction analysis. All isolates demonstrated anti-inflammatory activity in lipopolysaccharide-stimulated RAW264.7 cells. Notably, 3-5 showed a significant inhibitory effect on nitric oxide production, with IC50 values ranging from 0.79 to 4.73 µmol·L-1. Additionally, 4 and 5 exhibited moderate cytotoxic activities against three cancer cell lines, with IC50 values between 3.09 and 11.23 µmol·L-1.

Enantiomeric analysis of γ(δ)-lactones by reversed phase high performance liquid chromatography using amylose tris(5-chloro-2-methylphenylcarbamate) as stationary phase.

A Chiralpak AY-3R column was investigated for analytical enantiomeric separation of twelve racemic γ(δ)-lactones using reversed phase high performance liquid chromatography. Main influence factors, including organic modifier, flow rate and column temperature, were optimized. Five kinds of γ(δ)-lactones were successfully enantioseparated using the established method: γ-nonanolactone, δ-decalactone, δ-undecalactone, δ-dodecalactone and δ-tetradecalactone. Under optimized conditions, enantiomeric peak resolution (Rs) for the five γ(δ)-lactones reached more than 1.09, 1.08, 1.54, 1.43, and 1.11, respectively. Their chromatographic elution behavior was investigated using Van't Hoff equation and Van Deemter equation. It was found that an exothermic process occurred during enantiomeric separation of γ(δ)-lactones using this chromatographic column, and it showed a typical Van Deemter curve. Finally, this method was applied in enantiomeric ratio analysis of γ(δ)-lactones contents for purchased butter samples, and results confirmed the predominant content of the (R)-configuration of δ-dodecalactone in natural animal butter, while in margarine, an equal proportion of (R/S)-configuration of δ-dodecalactone was detected.

Synthesis and biological activity of thiophene bioisosteres of natural styryl lactone goniofufurone and related compounds.

Ten new thiophene derivatives related to goniofufurone have been obtained by multistep synthesis starting from d-glucose. The critical step of the synthesis was the Grignard reaction of 2-thienyl magnesium bromide with a protected dialdose, yielding the C-5 epimeric thiophene derivatives 9 and 10. The mixture was oxidized to the 5-keto derivative 11, which after deprotection was converted to the corresponding keto-lactone 14. Stereoselective reduction of 14 afforded the thiophene mimic of goniofufurone 3. Esterification of 3 with cinnamic or 4-fluorocinnamic acid gave hybrids 5-7. Synthesized analogues were evaluated for their in vitro cytotoxicity against several tumour cell lines. The vast majority of them showed better activity than lead 1. In the culture of K562 cells, compound 3 was more active than the commercial antitumour drug doxorubicin. Structural features of analogues important for their antiproliferative activities were identified by SAR analysis. Pro-apoptotic potential examination of compound 3 on the K562 cell line was performed using flow cytometry, double fluorescence staining and apoptotic morphology screening. Results show that this derivative induces cell membrane disruptions attributable to apoptosis and induces the apoptotic morphology, but decreasing simultaneously the population of cells in the subG1 phase of the cell cycle. The results further suggest that analogue 3 achieves strong cytotoxicity without causing DNA fragmentation. This is clearly indicated by the relatively low incidence of micronuclei, as well as the SAR analysis of all biological effects.

Isolation of Paraphaeoketones: A Plausible Biosynthetic Explanation for Paraphaeolactones via a Benzilic Acid Rearrangement Rather than a Favorskii Rearrangement.

Paraphaeoketones A-C (1-3) were isolated from the culture broth of Paraphaeosphaeria sp. KT4192. Their structures and relative configurations were determined using spectroscopic analysis and verified through density functional theory (DFT)-based chemical shift calculations. The absolute configurations of these compounds were determined by comparing the experimental electronic circular dichroism (ECD) spectra with those based on DFT calculations. We also propose a plausible biosynthetic route to 1-3. While our prior studies on the isolation and structural elucidation of paraphaeolactones (e.g., 4) led us to suggest a Favorskii rearrangement for their biosynthesis, the isolation of 2 prompted the proposal of an alternative biosynthesis for 4, featuring a benzilic acid rearrangement of 2. Moreover, an in vitro conversion of 2 into 4 was achieved successfully, suggesting that a biosynthetic pathway for paraphaeolactones involving a benzilic acid rearrangement is more plausible than the previously presumed Favorskii rearrangement pathway. Arguments based on DFT calculations for these pathways are also described.

Total Synthesis, Structure Reassignment, and Biological Evaluation of the Anti-Inflammatory Macrolactone 13-Hydroxy-14-deoxyoxacyclododecindione.

Herein, the first total synthesis of natural 13-hydroxy-14-deoxyoxacyclododecindione along with the revision of the proposed configuration is reported. This natural product, initially discovered in 2018, belongs to the oxacyclododecindione family, renowned for their remarkable anti-inflammatory and antifibrotic activities. The synthetic route involves an esterification/Friedel-Crafts-acylation approach and uses various triol fragments. It allows the preparation of different stereoisomers, including the (revised) natural product, two threo-derivatives, and two Z-isomers of the endocyclic C═C double bond. Furthermore, a late-stage inversion of the C-13 stereocenter could transform the originally proposed structure into the revised natural product. With this comprehensive set of compounds and the previously prepared (13R,14S,15R)-isomer, deeper insights into their structural properties and biological activities were obtained. A detailed analysis of the final macrolactones using spectroscopy (NMR, IR, UV-vis) and X-ray crystallography gave new insights such as the significance of the optical rotation for the elucidation of their configuration and the light-induced E/Z double-bond photoisomerization. The pharmacological potential of the compounds was underlined by remarkably low IC50 values in biological assays addressing the inhibition of cellular inflammatory responses.

Activity-Based Protein Profiling Identifies Protein Disulfide-Isomerases as Target Proteins of the Volatile Salinilactones.

The salinilactones, volatile marine natural products secreted from Salinispora arenicola, feature a unique [3.1.0]-lactone ring system and cytotoxic activities through a hitherto unknown mechanism. To find their molecular target, an activity-based protein profiling with a salinilactone-derived probe is applied that disclosed the protein disulfide-isomerases (PDIs) as the dominant mammalian targets of salinilactones, and thioredoxin (TRX1) as secondary target. The inhibition of protein disulfide-isomerase A1 (PDIA1) and TRX1 is confirmed by biochemical assays with recombinant proteins, showing that (1S,5R)-salinilactone B is more potent than its (1R,5S)-configured enantiomer. The salinilactones bound covalently to C53 and C397, the catalytically active cysteines of the isoform PDIA1 according to tandem mass spectrometry. Reactions with a model substrate demonstrated that the cyclopropyl group is opened by an attack of the thiol at C6. Fluorophore labeling experiments showed the cell permeability of a salinilactone-BODIPY (dipyrrometheneboron difluoride) conjugate and its co-localization with PDIs in the endoplasmic reticulum. The study is one of the first to pinpoint a molecular target for a volatile microbial natural product, and it demonstrates that salinilactones can achieve high selectivity despite their small size and intrinsic reactivity.

Discovery and properties of novel analogues of the aphid pheromones nepetalactone and nepetalactol.

BACKGROUND: Pheromones have unique advantages for pest control. Current aphid pheromone research focuses on alarm and sex pheromones. However, practical applications are limited so far, as (E)-ß-farnesene has only been investigated to a small extent as an alarm pheromone and only male aphids are targeted by sex pheromones. Previous literature reports electrophysiological responses and repellent behavior of asexual aphids to nepetalactone (1B), therefore our objective was to modify nepetalactone's structure to identify key fragments responsible for repellent effects, as guidance for subsequent modifications and further investigation. RESULTS: In this study, seven derivatives were designed and synthesized based on nepetalactol (1A) and nepetalactone (1B) as lead compounds. Free-choice tests, conducted using cowpea aphids (Aphis craccivora), revealed that the lactone moiety was crucial for the repellent activity, and the removal of the carbonyl group eliminated the repelling effect. Compound (±)1I, an analogue of nepetalactone (1B), demonstrated a significantly higher repellent value than nepetalactone (1B) at three different concentrations, and even at 0.1 mg/mL it maintained a considerable repellent effect (26.5%). Electrostatic potential and density functional theory calculations supported the importance of the carbonyl group for the repellent effects. CONCLUSION: The newly discovered para-pheromone (±)1I shows improved repellent effects and potential for development as a novel biological control agent. Based on our innovative findings, analogues with improved efficacy and properties can be designed and prepared. Our research contributes to understanding the effects of structural modifications on pheromone activity and properties, which is crucial for exploring novel pheromone-based products for crop protection. © 2024 Society of Chemical Industry.

Hirsutinolide- and Cadinanolide-type Sesquiterpene Lactones from Lessingianthus rubricaulis (Vernonieae, Asteraceae).

Sesquiterpene lactones are an important class of secondary metabolites frequently isolated from Lessingianthus genus that present a variety of biological properties, such as antimalarial, anti-inflammatory, antileishmanial, antitrypanosomal and anticancer. The limited phytochemical studies and the importance of this class of compounds isolated from Lessingianthus led us to study this genus. In this work, we focused on the phytochemical investigation and dereplication based on UHPLC-HRMS/MS and molecular networking of L. rubricaulis. Chemical investigation resulted in the isolation of several hirsutinolide-type sesquiterpene lactones including a new hirsutinolide derivative, 8,10α-hydroxy-1,13-bis-O-methylhirsutinolide, besides a cadinanolide and flavonoids. The dereplication study resulted in the identification of three known flavonoids, six known hirsutinolides and two known cadinanolides. Moreover, a fragmentation pathway for cadinanolide-type sesquiterpene lactones was proposed. These results contribute to chemotaxonomic studies and demonstrates the potential of Lessingianthus genus.

(R)-(+)-γ-Decalactone is Conserved in North America as a Pheromone Component of Osmoderma eremicola (Coleoptera: Scarabaeidae) and a Kairomone of Elater abruptus (Coleoptera: Elateridae).

The scarab genus Osmoderma (Coleoptera: Scarabaeidae) includes several large species called hermit beetles that develop within dead and decaying hardwood trees. Males of at least three Palearctic species produce the aggregation-sex pheromone (R)-(+)-γ-decalactone, including the endangered O. eremita (Scopoli). However, hermit beetles have received less attention in the western hemisphere, resulting in a large gap in our knowledge of the chemical ecology of Nearctic species. Here, we identify (R)-( +)-γ-decalactone as the primary component of the aggregation-sex pheromone of the North American species Osmoderma eremicola (Knoch). Field trials at sites in Wisconsin and Illinois revealed that both sexes were attracted to lures containing (R)-(+)-γ-decalactone or the racemate, but only males of O. eremicola produced the pheromone in laboratory bioassays, alongside an occasional trace of the chain-length analog γ-dodecalactone. Females of the congener O. scabra (Palisot de Beauvois) were also significantly attracted by γ-decalactone, suggesting further conservation of the pheromone, as were females of the click beetle Elater abruptus Say (Coleoptera: Elateridae), suggesting that this compound may have widespread kairomonal activity. Further research is needed to explore the behavioral roles of both lactones in mediating behavioral and ecological interactions among these beetle species.

Guaianolide sesquiterpenes and their activity from Artemisia mongolica.

Seven undescribed sesquiterpenes, including three dimeric guaianolide sesquiterpenes artemongolides G-I (1-3) and four sesquiterpene lactones artemanomalide D-G (16-19), along with seventeen known compounds isoabsinthin (4), absinthin (5), 11-eptabsinthin (6), 11, 11'-bis-epiabsinthin (7), 10', 11'- epiabsinthin (8), anabsinthin (9), isoanabsinthin (10), absinthin D (11), anabsin (12), caruifolin D (13), gnapholide (14), caruifolin C (15), 1ß(R),10ß(S)-dihydroxy-3-oxo-11ß (S)H-4,11(13)-guaien-6α(S),12-olide (20), 1α,6α,8α-trihydroxy-5α,7ßH-guaia-3,10(14),11(13)-trien-12-oic acid (21), 1α,6α,8α-trihydroxy-5α,7ßH-guaia-3,9,11(13)-trien-12-oic acid (22), argyinolide J (23), artabsinolide A (24) were isolated from the plant Artemisia mongolica. The structures were determined by interpreting NMR, HRESIMS and ECD data. The X-ray crystal structure of 4, 7 and 8 were reported for the first time. In the anti-vitiligo activity test, compounds 2, 7, 12, 23 and 24 demonstrated activity in promoting melanogenesis at a concentration of 50 µM in B16 cells, with 8-methoxypsoralan (8-MOP) as a positive control. Further research on the mechanism revealed that artemongolides H (2) enhance the expression of MITF and TRPs by upregulating p-Akt and p-GSK-3ß, leading to an increase in ß-catenin content in the cell cytoplasm. Subsequently, ß-catenin translocates into the nucleus, resulting in melanogenesis. The results supported the regulation of melanogenesis by artemongolide H (2) through the Akt/GSK3ß/ß-catenin signaling pathway. The anti-inflammatory results demonstrated that compounds 4, 5, 6, 9 and 14 can inhibit the upregulation of IL-6 mRNA and CCL2 mRNA expression. Compound 12 specifically inhibited the upregulation of IL-6 mRNA expression. These compounds exhibited significant anti-inflammatory activities. The activity results revealed that these sesquiterpene compounds have the potential to become lead compounds for the treatment of vitiligo and inflammatory diseases.

Intermediate product control in cascade reaction for one-pot production of ε-caprolactone by Escherichia coli.

ε-Caprolactone is an important non-toxic compound for polymer synthesis like polycaprolactone which has been widely used in drug delivery and degradable plastics. To meet the demand for a green economy, a bi-enzymatic cascade, consisting of an alcohol dehydrogenase (ADH) and a cyclohexanone monooxygenase (CHMO), was designed and introduced into Escherichia coli to synthesize ε-caprolactone from cyclohexanol with a self-sufficient NADPH-cofactor regeneration system. To further improve the catalytic efficiency, a carbonyl group-dependent colorimetric method using inexpensive 2,4-dinitrophenylhydrazine (DNPH) was developed for assay of cyclohexanone, an intermediate production of cascade reaction. It can be used to screen mutant strains with high catalytic efficiency from high-throughput library by detecting the absorbance value in microtiter plates (MTP) instead of gas chromatography (GC) analysis. Moreover, an RBS combinatorial library was constructed for balancing the expression of ADH and CHMO from two independent transcriptional units. After the high-throughput screening based on intermediate product control, an optimal variant with higher substrate tolerance and long-term stability was obtained from RBS combinatorial library. Through a fed-batch process, ε-caprolactone production reached 148.2 mM after 70 h of reaction under the optimized conditions, which was the highest yield achieved to date.

(4Z)-Lachnophyllum Lactone, a Metabolite with Phytotoxic and Antifungal Activity against Pests Affecting Mediterranean Agriculture: A New Versatile and Easy Scalable Parallel Synthesis.

A methodology for the total and modulable synthesis of (4Z)-lachnophyllum lactone (1), on a gram scale, is reported for the first time. The present work started with the design of a retrosynthetic pathway for the target compound, with the key step identified in Pd-Cu bimetallic cascade cross-coupling cyclization. (4Z)-Lachnophyllum lactone (1) is an acetylenic furanone previously isolated, in a low amount, from the organic extract of the autotrophic weedConyza bonariensis. Tested against the stem parasitic weed Cuscuta campestris in a seedling growth bioassay, (4Z)-lachnophyllum lactone (1) showed almost 85% of inhibitory activity up to 0.3 mM in comparison with the control. At the same concentration, the compound displayed radicle growth inhibitory activity of the root parasitic weeds Orobanche minor and Phelipanche ramosa higher than 70 and 40%, respectively. Surprisingly, the compound showed a high percentage of inhibition, up to 0.1 mM, on C. bonariensis seed germination too. This versatile synthetic strategy was also used to obtain two further natural analogues, namely, (4E)-lachnophyllum lactone (8) and (4Z,8Z)-matricaria lactone (9), that showed, in most cases, the same inhibitory trend with slight differences, highlighting the importance of the stereochemistry and unsaturation of the side chain. Furthermore, all of the compounds showed antifungal activity at 1 mM reducing the mycelial growth of the olive pathogen Verticillium dahliae. The design and implementation of scalable and modulable total synthesis on a gram scale of acetylenic furanones allow the production of a large amount of these natural products, overcoming the limit imposed by isolation from natural sources. The results of the present study pave the way for the development of ecofriendly bioinspired pesticides with potential application in agrochemical practices as alternative to synthetic pesticides.