Electronic Effects in a Green Protocol for (Hetero)Aryl-S Coupling

Aryl and heteroaryl iodides have been efficiently converted into the corresponding thioacetates in cyclopentyl methyl ether (CPME), a green solvent, under Cu catalysis. The chemoselectivity of the reaction is mainly controlled by electronic factors, enabling the conversion of both electron-rich and electron-deficient substrates into the corresponding thioacetates in good to excellent yields. The products can be easily deprotected to the corresponding thiolates to carry out additional synthetic transformations in situ. Surprisingly, despite CPME's relatively low dielectric constant, the reaction rate significantly increased when conducted under microwave irradiation conditions. This synthetic methodology exhibits a remarkable tolerance to functional groups, mild reaction conditions, and a wide substrate scope, utilizing a safe and inexpensive CuI pre-catalyst in the green solvent CPME. A non-aqueous workup allowing for the complete recovery of both catalyst and solvent makes this approach an environmentally sustainable protocol for C(sp2) sulfur functionalization. Additionally, the reaction shows selective cross-coupling with iodides in competition with chlorides and bromides, allowing its use in multistep syntheses. To demonstrate the potential of this methodology, it was applied to the high-yield synthesis of a photochromic dithienylethene, where a selective synthesis had not been reported before.

Design, synthesis and preclinical evaluation of muscarine receptor antagonists via a scaffold-hopping approach

Our research group recently identified a rearrangement product of pirenzepine as starting point for a comprehensive rational drug design approach towards orthosteric muscarinic acetylcholine receptor ligands. Chemical reduction and bioscaffold hop lead to the development of sixteen promising compounds featuring either a benzimidazole or carbamate moiety, all exhibiting comparable pharmacophoric characteristics. The synthesized compounds were characterized by NMR, HR-MS, and RP-HPLC techniques. Subsequent evaluation encompassed binding affinity assessment on CHO-hM1-5 cells, mode of action determination, and analysis of physico-chemical parameters. The CNS MPO score indicated favorable drug-like attributes and potential CNS activity for the antagonistic ligands. The most promising compounds displayed Ki-values within a desirable low nanomolar range, and their structural features allow for potential carbon-11 radiolabeling. Our optimization efforts resulted in compounds with a remarkable 138-fold increase in binding affinity compared to the previously mentioned rearrangement product towards human M5, suggesting their prospective utility in positron emission tomography applications.

Base-mediated homologative rearrangement of nitrogen-oxygen bonds of N-methyl-N-oxyamides

Due to the well known reactivity of C(O)-N functionalities towards canonical C1-homologating agents (e.g. carbenoids, diazomethane, ylides), resulting in the extrusion of the N-centered fragment en route to carbonyl compounds, formal C1-insertions within N-O bonds still remain obscure. Herein, we document the homologative transformation of N-methyl-N-oxyamides - with high tolerance for diverse O-substituents - into N-acyl-N,O-acetals. Under controlled basic conditions, the N-methyl group of the same starting materials acts as a competent precursor of the methylene synthon required for the homologation. The logic is levered on the formation of an electrophilic iminium ion (via N-O heterolysis) susceptible to nucleophilic attack by the alkoxide previously expulsed. The procedure documents genuine chemocontrol and flexibility, as judged by the diversity of substituents placed on both amide and nitrogen linchpins. The mechanistic rationale was validated through experiments conducted on D-labeled materials which unambiguously attributed the origin of the methylene fragment to the N-methyl group of the starting compounds.

Straightforward synthesis of bench-stable heteroatom-centered difluoromethylated entities via controlled nucleophilic transfer from activated TMSCHF2

The commercially available and experimentally convenient (bp 65 °C) difluoromethyltrimethylsilane (TMSCHF₂) is proposed as a valuable difluoromethylating transfer reagent for delivering the CHF₂ moiety to various heteroatom-based electrophiles. Upon activation with an alkoxide, a conceptually intuitive nucleophilic displacement directly furnishes in high yields the bench-stable analogues.

Consecutive and Selective Double Methylene Insertion of Lithium Carbenoids to Isothiocyanates: A Direct Assembly of Four-Membered Sulfur-Containing Cycles

A formal CH₂−CH₂ homologation conducted with C1 carbenoids on a carbon electrophile for the obtainment of a four‐membered cycle is reported. The logic proposes the consecutive delivery of two single nucleophilic CH₂ units to an isothiocyanate—as competent electrophilic partner—resulting in the assembling of a rare imino‐thietane cluster. The single synthetic operation procedure documents genuine chemocontrol, as indicated by the tolerance to various reactive elements decorating the starting materials. Significantly, the double homologation protocol is accomplished directly on a carbon electrophile, thus not requiring the installation of heteroatom‐centered manifolds (e.g. boron).

Direct and straightforward transfer of C1 functionalized synthons to phosphorous electrophiles for accessing gem-P-containing methanes

The direct transfer of different α-substituted methyllithium reagents to chlorinated phosphorous electrophiles of diverse oxidation state (phosphates, phosphine oxides and phosphines) is proposed as an effective strategy to synthesize geminal P-containing methanes. The methodology relies on the efficient nucleophilic substitution conducted on the P-chlorine linkage. Uniformly high yields are observed regardless the specific nature of the carbanion employed: once established the conditions for generating the competent nucleophile (LiCH₂Hal, LiCHHal₂, LiCH₂CN, LiCH₂SeR etc.) the homologated compounds are obtained via a single operation. Some P-containing formal carbanions have been evaluated in transferring processes, including the carbonyl-difluoromethylation of the opioid agent Hydrocodone.

Taking advantage of lithium monohalocarbenoid intrinsic α-elimination in 2-MeTHF: controlled epoxide ring-opening en route to halohydrins

The intrinsic degradative α-elimination of Li carbenoids somehow complicates their use in synthesis as C1-synthons. Nevertheless, we herein report how boosting such an α-elimination is a straightforward strategy for accomplishing controlled ring-opening of epoxides to furnish the corresponding β-halohydrins. Crucial for the development of the method is the use of the eco-friendly solvent 2-MeTHF, which forces the degradation of the incipient monohalolithium, due to the very limited stabilizing effect of this solvent on the chemical integrity of the carbenoid. With this approach, high yields of the targeted compounds are consistently obtained under very high regiocontrol and, despite the basic nature of the reagents, no racemization of enantiopure materials is observed.

Electrophilicity Scale of Activated Amides: 17 O NMR and 15 N NMR Chemical Shifts of Acyclic Twisted Amides in N-C(O) Cross-Coupling

The structure and properties of amides are of tremendous interest in organic synthesis and biochemistry. Traditional amides are planar and the carbonyl group non-electrophilic due to n_N →π*_C=O conjugation. In this study, we report electrophilicity scale by exploiting ¹⁷ O NMR and ¹⁵ N NMR chemical shifts of acyclic twisted and destabilized acyclic amides that have recently received major attention as precursors in N-C(O) cross-coupling by selective oxidative addition as well as precursors in electrophilic activation of N-C(O) bonds. Most crucially, we demonstrate that acyclic twisted amides feature electrophilicity of the carbonyl group that ranges between that of acid anhydrides and acid chlorides. Furthermore, a wide range of electrophilic amides is possible with gradually varying carbonyl electrophilicity by steric and electronic tuning of amide bond properties. Overall, the study quantifies for the first time that steric and electronic destabilization of the amide bond in common acyclic amides renders the amide bond as electrophilic as acid anhydrides and chlorides. These findings should have major implications on the fundamental properties of amide bonds.

Chemoselective Homologation-Deoxygenation Strategy Enabling the Direct Conversion of Carbonyls into (n+1)-Halomethyl-Alkanes

The sequential installation of a carbenoid and a hydride into a carbonyl, furnishing halomethyl alkyl derivatives, is reported. Despite the employment of carbenoids as nucleophiles in reactions with carbon-centered electrophiles, sp³-type alkyl halides remain elusive materials for selective one-carbon homologations. Our tactic levers on using carbonyls as starting materials and enables uniformly high yields and chemocontrol. The tactic is flexible and is not limited to carbenoids. Also, diverse carbanion-like species can act as nucleophiles, thus making it of general applicability.

Enhanced arecoline derivatives as muscarinic acetylcholine receptor M1 ligands for potential application as PET radiotracers

Supported by their involvement in many neurodegenerative disorders, muscarinic acetylcholine receptors (mAChRs) are an interesting target for PET imaging. Nevertheless, no radiotracer is established in clinical routine. Within this work we aim to develop novel PET tracers based on the structure of arecoline. Fifteen novel arecoline derivatives were synthesized, characterized and tested for their affinity to the mAChRs M1-M5 and the conceivable off-target acetylcholinesterase. Five arecoline derivatives and arecoline were labeled with carbon-11 in good yields. Arecaidine diphenylmethyl ester (3b), arecaidine bis(4-fluorophenyl)methyl ester (3c) and arecaidine (4-bromophenyl)(4-fluorophenyl)methyl ester (3e) showed a tremendous gain in mAChR affinity compared to arecoline and a pronounced subtype selectivity for M1. Metabolic stability and serum protein binding of [¹¹C]3b and [¹¹C]3c were in line with properties of established brain tracers. Nonspecific binding of [¹¹C]3c was prevalent in kinetic and endpoint experiment on living cells as well as in autoradiography on native mouse brain sections, which motivates us to decrease the lipophilicity of this substance class prior to in vivo experiments.

Direct and Chemoselective Electrophilic Monofluoromethylation of Heteroatoms (O-, S-, N-, P-, Se-) with Fluoroiodomethane

The commercially available fluoroiodomethane represents a valuable and effective electrophilic source for transferring the CH₂F unit to a series of heteroatom-centered nucleophiles under mild basic conditions. The excellent manipulability offered by its liquid physical state (bp 53.4 °C) enables practical and straightforward one-step nucleophilic substitutions to retain the chiral information embodied, thus allowing it to overcome de facto the requirement for fluoromethylating agents with no immediate access. The high-yielding methodology was successfully applied to a variety of nucleophiles including a series of drugs currently in the market.

Straightforward chemoselective access to unsymmetrical dithioacetals through a thiosulfonate homologation-nucleophilic substitution sequence

A two-step electrophilic sulfur homologation strategy for building up unsymmetrical dithioacetals.

Highly chemoselective difluoromethylative homologation of iso(thio)cyanates: expeditious access to unprecedented α,α-difluoro(thio)amides

The new motif - α,α-difluoromethyl thioamide - has been assembled starting from isothiocyanate (as thioamide precursor) and a formal difluoromethyl-carbanion generated from commercially available TMSCHF2. Upon proper activation of this reagent with potassium tert-amylate, the high-yielding transfer of the difluorinated nucleophile takes place under high chemocontrol. Various sensitive functionalities (e.g. ester, nitrile, nitro, azido groups) can be accommodated across the isothiocyanate core, thus allowing a wide scope. The methodology is highly flexible and adaptable to prepare analogous α,α-difluoromethyl oxoamides by conveniently using isocyanates as the electrophilic building-blocks.

Direct and Chemoselective Synthesis of Tertiary Difluoroketones via Weinreb Amide Homologation with a CHF2-Carbene Equivalent

The homologation of Weinreb amides into difluoromethylketones with a formal nucleophilic CHF₂ transfer agent is reported. Activating TMSCHF₂ with potassium tert-amylate enables a convenient access to the difluorinated homologation reagent, which adds to the acylating partners. The high chemoselectivity showcased in the presence of variously multifunctionalized Weinreb amides, jointly with uniformly high yields, enables the strategy of general applicability without requiring any stabilization element for the putative carbanion.

17O NMR and 15N NMR chemical shifts of sterically-hindered amides: ground-state destabilization in amide electrophilicity

The structure and spectroscopic properties of the amide bond are a topic of fundamental interest in chemistry and biology. Herein, we report 17O NMR and 15N NMR spectroscopic data for four series of sterically-hindered acyclic amides. Despite the utility of 17O NMR and 15N NMR spectroscopy, these methods are severely underutilized in the experimental determination of electronic properties of the amide bond. The data demonstrate that a combined use of 17O NMR and 15N NMR serves as a powerful tool in assessing electronic effects of the amide bond substitution as a measure of electrophilicity of the amide bond. Notably, we demonstrate that steric destabilization of the amide bond results in electronically-activated amides that are comparable in terms of electrophilicity to acyl fluorides and carboxylic acid anhydrides.

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

Fused pyrazole ring systems are common structural motifs of numerous pharmaceutically important compounds. Nevertheless, access to derivatives of the aromatic 2H-furo[2,3-c]pyrazole ring system is still quite limited, and their chemistry and functional properties remain largely underexplored. The current study investigates routes to construct this system from easily accessible starting materials using metal-catalyzed reactions. A simple and efficient procedure to access the 2H-furo[2,3-c]pyrazole ring system was developed by employing the silver(I) ion-mediated ring-closure reaction of 4-alkynyl-3-hydroxy-1-phenyl-1H-pyrazoles as a key step. The required intermediate hydroxyalkynyl substrates for this reaction were prepared by a Pd-catalyzed coupling of 4-iodo-1-phenyl-1H-pyrazol-3-ol with ethyne derivatives. The structures of the obtained target compounds were unequivocally confirmed by detailed ¹H, ¹³C and ¹⁵N NMR spectroscopic experiments, HRMS and a single-crystal X-ray diffraction analyses. This silver(I)-mediated 5-endo-dig cyclization of readily available 4-alkynyl-3-hydroxy-1H-pyrazoles can be used as an efficient method to access many novel 2,5-disubstituted 2H-furo[2,3-c]pyrazoles.

Sustainable Asymmetric Organolithium Chemistry: Enantio- and Chemoselective Acylations through Recycling of Solvent, Sparteine, and Weinreb "Amine"

The well-established Hoppe-Beak chemistry, which involves enantioselective generation of organolithium compounds in the presence of (-)-sparteine, was revisited and applied to unprecedented acylations with Weinreb amides to access highly enantioenriched α-oxyketones and cyclic α-aminoketones. Recycling of the sustainable solvent cyclopentyl methyl ether, sparteine, and the released Weinreb "amine" [HNMe(OMe)] was possible through a simple work-up procedure that enabled full recovery of these precious materials. The methodology features a robust scope and flexibility, thus allowing the enantioselective preparation of scaffolds amenable of further derivatization.

Telescoped, Divergent, Chemoselective C1 and C1-C1 Homologation of Imine Surrogates: Access to Quaternary Chloro- and Halomethyl-Trifluoromethyl Aziridines

A conceptually novel, high‐yielding, mono‐ or bis‐homologation was realized with lithium halocarbenoids and enables the one‐step, fully chemocontrolled assembly of a new class of quaternary trifluoromethyl aziridines. Trifluoroacetimidoyl chlorides (TFAICs) act as convenient electrophilic platforms, enabling the addition of either one or two homologating elements by simply controlling the stoichiometry of the process. Mechanistic studies highlighted that the homologation event, carried out with two different carbenoids (LiCH₂Cl and LiCH₂F), leads to fluoromethyl analogues in which the first nucleophile is employed for constructing the cycle and the second for decorating the resulting molecular architecture.

Modular and Chemoselective Strategy for the Direct Access to α-Fluoroepoxides and Aziridines via the Addition of Fluoroiodomethyllithium to Carbonyl-Like Compounds

An expeditious, high-yielding synthesis of rare α-fluoroepoxides and α-fluoroaziridines through the addition of the unkown fluoroiodomethyllithium (LiCHIF)-formed via deprotonation the commercially available fluoroiodomethane with a lithium amide base-to carbonyl-like compounds is documented. The ring-closure reactions, leading to α-fluorinated three-membered heterocycles, rely on the diversely reactive C-I and C-F bonds. Excellent chemoselectivity was observed in the presence of highly sensitive functionalities-aldehyde, ketone, nitrile, alkene-which remained untouched during the homologation sequence.

Chemoselective reduction of isothiocyanates to thioformamides mediated by the Schwartz reagent

Thioformamides are easily prepared – under full chemocontrol – through the partial reduction of isothiocyanates with the in situ generated Schwartz reagent.

Design, Synthesis, and Pharmacological Evaluation of Novel β2/3 Subunit-Selective γ-Aminobutyric Acid Type A (GABAA) Receptor Modulators

Subunit-selective modulation of γ-aminobutyric acid type A receptors (GABA_AR) is considered to exert fewer side effects compared to unselective clinically used drugs. Here, the β2/3 subunit-selective GABA_AR modulators valerenic acid (VA) and loreclezole (LOR) guided the synthesis of novel subunit-selective ligands with simplified structures. We studied their effects on GABA_ARs expressed in Xenopus laevis oocytes using two-microelectrode voltage clamp technique. Five compounds showed significantly more efficacious modulation of GABA-evoked currents than VA and LOR with retained potency and selectivity. Compound 18 [( E)-2-Cyano-3-(2,4-dichlorophenyl)but-2-enamide] induced the highest maximal modulation of GABA-induced chloride currents ( E_max: 3114 ± 242%), while 12 [( Z)-3-(2,4-dichlorophenyl)but-2-enenitrile] displayed the highest potency (EC₅₀: 13 ± 2 μM). Furthermore, in hippocampal neurons 12 facilitated phasic and tonic GABAergic inhibition, and in vivo studies revealed significantly more potent protection against pentylenetetrazole (PTZ)-induced seizures compared to VA and LOR. Collectively, compound 12 constitutes a novel, simplified, and subunit-selective GABA_AR modulator with low-dose anticonvulsant activity.

An unusual thionyl chloride-promoted C-C bond formation to obtain 4,4'-bipyrazolones

Dialkyl 5,5'-dioxo-4,4'-bipyrazole-4,4'-dicarboxylates are readily obtained by the reaction of 5-hydroxypyrazole-4-carboxylates in refluxing thionyl chloride. The obtained diesters can be transformed into the corresponding 4,4'-bipyrazoles via alkaline hydrolysis and subsequent decarboxylation. Detailed NMR spectroscopic investigations (¹H, ¹³C, ¹⁵N) were undertaken with all products prepared. Moreover, the structure of a representative 5,5'-dioxo-4,4'-bipyrazole-4,4'-dicarboxylate was confirmed by X-ray crystal structure analysis.

Synthesis and anti-mitotic activity of 2,4- or 2,6-disubstituted- and 2,4,6-trisubstituted-2H-pyrazolo[4,3-c]pyridines

An efficient synthetic route for the synthesis of 2H-pyrazolo[4,3-c]pyridines, primarily varying by the substituents at the 2-, 4- and 6-positions, is described here. A Sonogashira-type cross-coupling reaction was employed to yield 3-alkynyl-1H-pyrazole-4-carbaldehydes, ethanones and propanones from the corresponding 1H-pyrazol-3-yl trifluoromethanesulfonates. Subsequent treatment of the coupling products with dry ammonia afforded a versatile library of 2H-pyrazolo[4,3-c]pyridines, which were then evaluated for their cytotoxicity against K562 and MCF-7 cancer cell lines. The most potent of these compounds displayed low micromolar GI₅₀ values in both cell lines. Active compounds induced dose-dependent cell-cycle arrest in mitosis, as shown by flow cytometric analysis of DNA content and phosphorylation of histone H3 at serine-10. Moreover, biochemical assays revealed increased activities of caspases-3/7 in treated cells, specific fragmentation of PARP-1, and phosphorylation of Bcl-2, collectively confirming apoptosis as the mechanism of cell death.

Homologation of halostannanes with carbenoids: a convenient and straightforward one-step access to α-functionalized organotin reagents

A direct, single synthetic homologative transformation of halostannanes into mono- or di-substituted methyl analogues is documented.

Exploiting a "Beast" in Carbenoid Chemistry: Development of a Straightforward Direct Nucleophilic Fluoromethylation Strategy

The first direct and straightforward nucleophilic fluoromethylation of organic compounds is reported. The tactic employs a "fleeting" lithium fluorocarbenoid (LiCH₂F) generated from commercially available fluoroiodomethane. Precise reaction conditions were developed for the generation and synthetic exploitation of such a labile species. The versatility of the strategy is showcased in ca. 50 examples involving a plethora of electrophiles. Highly valuable chemicals such as fluoroalcohols, fluoroamines, and fluoromethylated oxygenated heterocycles could be prepared in very good yields through a single synthetic operation. The scalability of the reaction and its application to complex molecular architectures (e.g., steroids) are documented.

Efficient Access to All-Carbon Quaternary and Tertiary α-Functionalized Homoallyl-type Aldehydes from Ketones

β,γ-Unsaturated aldehydes with all-carbon quaternary or tertiary α-centers were rapidly assembled from ketones through a unique synthetic operation consisting of 1) C₁ homologation, 2) Lewis acid mediated epoxide-aldehyde isomerization, and 3) electrophilic trapping. The synthetic equivalence of a vinyl oxirane and a β,γ-unsaturated aldehyde is the key concept of this previously undisclosed tactic. Mechanistic studies and labeling experiments suggest that an aldehyde enolate is a crucial intermediate. The homologating carbenoid formation plays a critical role in determining the chemoselectivity.

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

A synthesis of tetrasubstituted pyrazoles containing two, three or four pyridinyl substituents is described. Hence, the reaction of 1,3-dipyridinyl-1,3-propanediones with 2-hydrazinopyridine or phenylhydrazine, respectively, affords the corresponding 1,3,5-trisubstituted pyrazoles. Iodination at the 4-position of the pyrazole nucleus by treatment with I2/HIO3 gives the appropriate 4-iodopyrazoles which served as starting materials for different cross-coupling reactions. Finally, Negishi cross-coupling employing organozinc halides and Pd catalysts turned out to be the method of choice to obtain the desired tetrasubstituted pyrazoles. The formation of different unexpected reaction products is described. Detailed NMR spectroscopic investigations (1H, 13C, 15N) were undertaken with all products prepared. Moreover, the structure of a condensation product was confirmed by crystal structure analysis.

Eulophia macrobulbon - an orchid with significant anti-inflammatory and antioxidant effect and anticancerogenic potential exerted by its root extract

BACKGROUND

The Orchidaceae family is one of the largest families of flowering plants. Orchids are widely used for the traditional herbal medicine, acting as aphrodisiac, antisepic, antimicrobial, anti-cancer agent, etc.

PURPOSE

This study was designed to elucidate the anti-inflammatory, antioxidant and cytotoxic potential of a 50% ethanolic extract of Eulophia macrobulbon roots (EME) in vitro, an orchid growing in Southern Asia. Furthermore, the main active compounds were isolated, and the bioactivity of the single constituents was determined.

METHODS

The anti-inflammatory activity of EME and its compounds was evaluated by the secretion of pro- and anti-inflammatory cytokines and by the expression of inducible nitric oxide synthase (iNOS) in a lipopolysaccharide (LPS)-stimulated macrophage model, as determined by an enzyme linked immunosorbent assay (ELISA) and Western blot. Antioxidant activity was assessed using a DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) photometric assay. Cytotoxic effects were determined using a colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)-assay.

RESULTS

EME and its compounds significantly reduced the production of the proinflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α), the expression of iNOS and subsequently increased the production of the anti-inflammatory cytokine interleukin 10 (IL-10) in LPS-stimulated macrophages. Additionally it could be demonstrated that EME is rich in radical scavengers. Furthermore, EME and its components showed notable cytotoxic effects on the human cervical adenocarcinoma cell line HeLa, the human colorectal adenocarcinoma cell line CaCo-2 and the human breast adenocarcinoma cell line MCF-7. The most active constituents were identified as 4-methoxy-9,10-dihydro-2,7-phenanthrenediol (8), 4-methoxy-2,7-phenanthrenediol (9), 1,5-dimethoxy-2,7-phenanthrenediol (10), 1,5,7-trimethoxy-2,6-phenanthrenediol (11), 1-(4-hydroxybenzyl)-4,8-dimethoxy-2,7-phenanthrenediol (15).

CONCLUSION

Based on this data, EME provides various beneficial anti-inflammatory, antioxidant and cytotoxic attributes and may be used as herbal remedy in the pharmaceutical or food industries.

Evidence and isolation of tetrahedral intermediates formed upon the addition of lithium carbenoids to Weinreb amides and N-acylpyrroles

Trapping tetrahedral intermediates from Weinreb amides andN-acylpyrroles.

A greener and efficient access to substituted four- and six-membered sulfur-bearing heterocycles

The regioselective functionalization of four- and six-membered cyclic sulfones was investigated using a lithiation/functionalization strategy.

Anti-inflammatory Effects of Compounds from Polygonum odoratum

Polygonum odoratum is an edible plant traditionally used as an antidiabetic, antimicrobial, anti-inflammatory, and antitumor agent in Asia. The aim of the study was to evaluate the anti-inflammatory effect of P. odoratum and the isolation and characterization of its main fractions. Extracts of the aerial parts were tested for anti-inflammatory activity as indicated by a change in the cytokine secretion in lipopolysaccharide-stimulated macrophages. After separation of the extract by reversed-phase high-performance liquid chromatography, the anti-inflammatory activity of the fractions was determined. Furthermore, the two main fractions were identified by nuclear magnetic resonance spectroscopy ((1)H- and (13)C-NMR). The ethanolic extract significantly reduced IL-6 secretion (IC50 25 pg/mL). The two main fractions (5 and 7) significantly decreased IL-6 production with an IC(50) of 102 μM (5) and 77 μM (7), respectively, and were identified as scutellarein-7-glucoside (5) and quercitrin (7). Since inflammation plays a major role in various diseases with high prevalence globally, it may be of importance that P. odoratum and its main constituents scutellarein-7-glucoside and quercitrin can be used as either an alternative or complementary treatment. Additionally, both are glycosides and their activity may be enhanced tremendously by deglycosylation by the gut microbiota.

The use of the Comins-Meyers Amide in Synthetic Chemistry: An Overview

Formylation reactions are fundamental operations in synthetic chemistry allowing the incorporation into a given structure formyl groups amenable to further derivatization. Conceptually, the introduction of such groups through the reaction between an electrophilic donor and a nucleophilic acceptor ( i.e. organometallic reagent) constitutes a reliable technique with widespread applications. In this Highlight, we summarize the effectiveness of the so called Comins-Meyers amide - [2-( N-methyl- N-formylamino]pyridine – in such a chemistry with vistas to the synthesis of natural products and biologically active substrates.

The Use of the Comins-Meyers Amide in Synthetic Chemistry: an Overview

Formylation reactions are fundamental operations in synthetic chemistry allowing the incorporation into a given structure formyl groups amenable to further deiivatization. Conceptually, the introduction of such groups through the reaction between an electrophilic donor and a nucleophilic acceptor (i.e. organometallic reagent) constitutes a reliable technique with widespread applications. In this Highlight, we summarize the effectiveness of the so called Comnins-Meyers amide - [2-(N-methyl-N-formylamino]pyridine - in such a chemistry with vistas to the synthesis of natural products and biologically active substrates.