Arylnaphthalene Lactone Research Articles

Evaluation of potency and metabolic stability of diphyllin-derived Vacuolar-ATPase inhibitors

Diphyllin is a naturally occurring lignan comprised of an aryl naphthalene lactone scaffold that demonstrates beneficial biological activities in disease models of cancer, obesity, and viral infection. A target of diphyllin and naturally occurring derivatives is the vacuolar ATPase (V-ATPase) complex. Although diphyllin-related natural products are active with in vitro models for viral entry, the potencies and unknown pharmacokinetic properties limit well-designed in vivo evaluations. Previous studies demonstrated that diphyllin derivatives have the utility of blocking the Ebola virus cell entry pathway. However, diphyllin shows limited potency and poor oral bioavailability in mice. An avenue to improve the potency was used in a new library of synthetic derivatives of diphyllin. Diphyllin derivatives exploiting ether linkages at the 4-position with one-to-three carbon spacers to an oxygen or nitrogen atom provided compounds with EC50 values ranging from 7 to 600 nM potency and selectivity up to >500 against Ebola virus in infection assays. These relative potencies are reflected in the Ebola virus infection of primary macrophages, a cell type involved in early pathogenesis. A target engagement study reveals that reducing the ATPV0a2 protein expression enhanced the potency of diphyllin derivatives to block EBOV entry, consistent with effects on the endosomal V-ATPase function. Despite the substantial enhancement of antiviral potencies, limitations were identified, including rapid clearance predicted by in vitro microsome stability assays. However, compounds with similar or improved half-lives relative to diphyllin demonstrated improved pharmacokinetic profiles in vivo. Importantly, these derivatives displayed suitable plasma levels using oral administration, establishing the feasibility of in vivo antiviral testing.

Intramolecular Heteroatom and Styryl Diels-Alder Reactions, Asymmetric Cycloadditions of Chiral 3-Phenylallyl Maleic Esters.

Polycyclic aryl naphthalene and tetralin dihydro arylnaphthalene lactone lignans possess anticancer and antibiotic activity. Related furo[3,4-c]pyranones, typified by the sequester-terpenoid isobolivianine, show similar antiproliferative bioactivity. Efficient syntheses of compounds featuring these polycyclic cores have proven challenging due to low yields and poor stereoselectivity. We report the synthesis of chiral cinnamyl but-2-enanoates and 3,3-diphenylallyl-but-2-enoates 1 as new Diels-Alder substrates. These compounds undergo [4 + 2]-cycloadditions to give furo[3,4-c]pyranones 2 in good yield (70%) and diastereoselectivity (7:1), together with naphthyl 3 and dihydronaphthyl tetralins 4 as minor products. Molecular structures and stereochemistries of the major products were verified using X-ray diffraction. Density functional theory calculations revealed that the cycloaddition process involves a bispericyclic/ambimodal process where there is a single transition state that leads to both intramolecular styryl Diels-Alder (ISDA) 3, 4 and intramolecular hetero Diels-Alder (IHDA) cycloadducts 2. With the elevated temperature conditions after cycloaddition, the resulting ISDA cycloadduct either undergoes [3,3]-sigmatropic rearrangement to the more stable major IHDA product or aromatization leading to the phenyltetralin.

Total synthesis of justicidin B, justicidin E, and taiwanin C: A general and flexible approach toward the synthesis of natural arylnaphthalene lactone lignans.

Lignans are widely present in traditional medicinal plants. Many natural arylnaphthalene lactone lignans (NALLs) isolated from the genera Justicia, Haplophyllum, and Phyllanthus possess interesting biological activities. Herein, we report a general strategy for the total synthesis of this kind of lignans. Features of this new approach are an aryl-alkyl Suzuki cross-coupling to introduce the dioxinone unit, a cation-induced cyclization to construct the aryl dihydronaphthalene, and base-mediated oxidative aromatization to furnish the arylnaphthalene core. By incorporating these key transformations, the total syntheses of justicidins B and E and taiwanin C covered type I and type II NALLs were accomplished.

4-Phenylnaphtho[2,3-c]furan-1(3H)-one, 9-Phenylnaphtho[2,3-c]furan-1(3H)-one and 3a,4-Dihydro-9-phenylnaphtho[2,3-c]furan-1(3H)-one Crystal Structures

The crystal structures are reported for two unsubstituted arylnaphthalene lactones, 4-phenylnaphtho[2,3-c]furan-1(3H)-one (2), 9-phenylnaphtho[2,3-c]furan-1(3H)-one (3) and a non-aromatic dihydro arylnaphthene lactone, 3a,4-dihydro-9-phenylnaphtho[2,3-c]furan-1(3H)-one (5). There are only minor differences in the geometrical parameters of these structures. However, in certain cases, both isomers of arylnaphthalene lactones (termed Type I and Type II) were found in the same asymmetric unit cell.

Transition Metal-Mediated Annulation Approaches for Synthesis of Arylnaphthalene Lignan Lactones.

Arylnaphthalene lignan lactones belong to a class of natural lignans, and more than 60 analogs have been isolated. Their pharmacological activities as well as unique structural features have attracted considerable attention from medicinal and synthetic chemists. Since the first synthesis in 1895, many synthetic methodologies with ionic or pericyclic reaction mechanisms have been reported. Transition metal catalysts sometimes provide exceptional synthetic versatility for the syntheses of natural compounds. Recently, transition metal-mediated methodologies were investigated for the construction of basic scaffolds of arylnaphthalene lignan lactones. Five kinds of transition metal catalysts containing gold, manganese, nickel, palladium, and silver have been explored. Most of the metal catalysts successfully created arylnaphthalene lactones by intermolecular or intramolecular annulative cyclization. In this review, all reports of transition metal-mediated annulative construction of arylnaphthalene lignan lactones were compiled, and synthetic approaches, mechanistic aspects, and successful applications were discussed.

Arylnaphthalene lactone analogues: synthesis and development as excellent biological candidates for future drug discovery.

Arylnaphthalene lactones are natural products extracted from a wide range of different parts of plants. The progressing interest in the synthesis of these compounds is due to their significant biological activities, which have made them potential candidates in drug discovery and development. This review mainly covers recent developments in the synthesis and biological applications of arylnaphthalene lactone analogs.

An Optimized and General Synthetic Strategy To Prepare Arylnaphthalene Lactone Natural Products from Cyanophthalides

A simple method for the preparation of arylnaphthalene lactone natural products was developed and used to synthesize diphyllin (10), justicidin A (12), cilinaphthalide B (13), taiwanin E (15), chinensinaphthol (16), taiwanin E methyl ether (17), chinensinaphthol methyl ether (18), justicidin C (21), and justicidin D (22). Key steps of the syntheses include the Hauser–Kraus annulation of cyanophthalides 7a and 7b and Suzuki–Miyaura cross‐coupling reactions between arylnaphthalene lactones that contain a sulfonate group (i.e., 9, 14, 19, and 20) and various potassium aryltrifluoroborates.

Synthesis of arylnaphthalene lignan lactone using benzoin condensation, intramolecular thermal cyclization and Suzuki coupling

Arylnaphthalene lactones, which are natural lignans and isolated from a wide range of plants, exhibit significant biological activity, including anticancer and antiviral activities. In this work, we have developed a versatile and convergent synthetic method for arylnaphthalene lactones, which involves the use of benzoin condensation and thermal intramolecular cyclization for preparing the key intermediate, naphthol. A high-yielding Suzuki reaction is utilized to introduce the aryl group to the C9 position of the naphthalene lactones, which allows for the construction of the arylnaphthalene lactone skeleton.

Intramolecular dehydro-Diels-Alder reaction affords selective entry to arylnaphthalene or aryldihydronaphthalene lignans.

Intramolecular dehydro-Diels–Alder (DDA) reactions are performed affording arylnaphthalene or aryldihydronaphthalene lactones selectively as determined by choice of reaction solvent. This constitutes the first report of an entirely selective formation of arylnaphthalene lactones utilizing DDA reactions of styrene-ynes. The synthetic utility of the DDA reaction is demonstrated by the synthesis of taiwanin C, retrohelioxanthin, justicidin B, isojusticidin B, and their dihydronaphthalene derivatives. Computational methods for chemical shift assignment are presented that allow for regioisomeric lignans to be distinguished.

Synthesis of naphthalene amino esters and arylnaphthalene lactone lignans through tandem reactions of 2-alkynylbenzonitriles

Tandem reaction of 2-alkynylbenzonitriles with a Reformatsky reagent turned out to be a novel and efficient approach toward 1-aminonaphthalene-2-carboxylates. Interestingly, with 2-(3-hydroxyprop-1-ynyl)benzonitriles as the substrates, a more sophisticated cascade process occurred to give 9-aminonaphtho[2,3-c]furan-1(3H)-ones in good yields. By using this tandem reaction as a key step, a concise and versatile synthetic strategy for the total synthesis of arylnaphthalene lactone lignans has been developed.

Regioselective route for arylnaphthalene lactones: convenient synthesis of taiwanin C, justicidin E, and daurinol

Arylnaphthalene lactones are natural products which can be isolated from a wide range of plants and have the significant biological activities including cytotoxicity, antimicrobial, diuretic, and ion channel blocking. The drawback of the previous intramolecular Diels–Alder reaction of 3-arylprop-2-ynyl 3-arylpropiolates was to generate two regioisomers of arylnaphthalene lactone without selectivity. Herein, we report a convenient and regioselective synthesis method in which the intramolecular Diels–Alder reaction of an arylalkene–arylalkyne and subsequent DDQ oxidation was used for Type I and Type II arylnaphthalene lactones, respectively. We demonstrated the synthesis of three lignans, taiwanin C (Type I), justicidin E (Type II), and daurinol (Type I and anti-cancer activity).

Synthesis of Arylnaphthalene Lignan Scaffold by Gold-Catalyzed Intramolecular Sequential Electrophilic Addition and Benzannulation

An intramolecular approach to generate compounds containing an arylnaphthalene lignan scaffold in high yields is presented. It involves a sequential intramolecular electrophilic attack of carbonyl on arylalkyne followed by benzannulation catalyzed by gold salt. AuCl(3) in combination with AgSbF(6) works better to effect this transformation. Selected products have been converted into arylnaphthalene lactone natural products such as justicidin E, taiwanin C, and retrojusticidin B.

Silver-Catalyzed One-Pot Synthesis of Arylnaphthalene Lactone Natural Products

Naturally occurring arylnaphthalene lactone lignans have demonstrated a variety of valuable medicinal chemistry properties and have therefore been of continued interest to drug discovery research. Our group has demonstrated a silver-catalyzed one-pot synthesis of the arylnaphthalene lactone core using carbon dioxide, phenylpropargyl chloride, and phenylacetylene. This new approach has been employed in the synthesis of six arylnaphthalene lactone natural products: retrochinensin (1), justicidin B (2), retrojusticidin B (3), chinensin (4), justicidin E (5), and taiwanin C (6). Additionally, an arylnaphthalene lactone regioisomer was isolated (9), which we refer to as isoretrojusticidin B.

Advances in the methodology of a multicomponent synthesis of arylnaphthalene lactones

Material and energy inefficiencies in total synthesis can arise from a lack of step economy. Multicomponent syntheses have the potential to optimize step economy and, in turn, to minimize not only waste, but also exposure to hazardous chemicals. Therefore, multicomponent syntheses are of immense interest to the field of Green Chemistry. Herein is described a multicomponent synthesis of arylnaphthalene lignan lactones, which are valuable natural products with promising anticancer and antiviral properties. In an effort to improve our previously reported one-pot, multicomponent synthesis an approach using phenylacetylene, phenylpropargyl chloride, carbon dioxide, catalytic silver iodide, and catalytic 18-crown-6 ether was developed. This methodology was then successfully applied to the preparation of dehydrodimethylconidendrin and its regioisomer, dehydrodimethylretroconidendrin.

Synthesis of Natural Lignan Arylnaphthalene Lactones, Daurinol and Retrochinensin

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of Natural Lignan Arylnaphthalene Lactones, Daurinol and RetrochinensinPaul T. Anastas and Robert StevensonCite this: J. Nat. Prod. 1991, 54, 6, 1687–1691Publication Date (Print):November 1, 1991Publication History Published online1 July 2004Published inissue 1 November 1991https://doi.org/10.1021/np50078a035RIGHTS & PERMISSIONSArticle Views321Altmetric-Citations16LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (323 KB) Get e-Alerts Get e-Alerts

Matairesinol as precursor of Podophyllum lignans

The dibenzylbutyrolactone lignan (−)-[ 14C]matairesinol was efficiently incorporated into the aryltetralin lactone lignans podophyllotoxin, 4′-demethylpodophyllotoxin, β-peltatin, α-peltatin and 4′-demethyldesoxypodophyllotoxin in one or more of the plant systems Podophyllum hexandrum root, P. peltatum leaf or Diphylleia cymosa leaf. This demonstrates matairesinol to be a common precursor of the 3′,4′,5′-trimethoxy and 4′-hydroxy-3′,5′-dimethoxy groups of Podophyllum lignans, and it may represent the branch-point compound to the two series of compounds. No incorporation of matairesinol into the arylnaphthalene lactone lignan diphyllin in D. cymosa was detected.

Improved Methods of Synthesis of Lignan Arylnaphthalene Lactones via Arylpropargyl Arylpropiolate Esters

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTImproved Methods of Synthesis of Lignan Arylnaphthalene Lactones via Arylpropargyl Arylpropiolate EstersRobert Stevenson and James V. WeberCite this: J. Nat. Prod. 1989, 52, 2, 367–375Publication Date (Print):March 1, 1989Publication History Published online1 July 2004Published inissue 1 March 1989https://doi.org/10.1021/np50062a024RIGHTS & PERMISSIONSArticle Views458Altmetric-Citations32LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (591 KB) Get e-Alerts Get e-Alerts

Synthesis of lignan lactones by conjugate addition of thioacetal carbanions to butenolide

The conjugate addition of carbanions dervied from arylbis(phenylthio)methanes to butenolide followed by trapping of the enolate anion so generated by a benzyl halide affords adducts (8) containing the basic lignan skeleton. Desulphurisation of these adducts by Raney nickel affords a short efficient synthesis of trans-dibenzylbutyrolactones and this route has been used to prepare enterolactone (9c) and an antitumour lignan (9b), derived from Bursera schlechtendalii. Treatment of the adducts (8) with heavy-metal salts induces cyclisation leading to arylnaphthalene lactones, including retrojusticidin B (13).