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Navarro M, Moreira I, Arnaez E, Quesada S, Azofeifa G, Vargas F, Alvarado D, Chen P. Flavonoids and Ellagitannins Characterization, Antioxidant and Cytotoxic Activities of Phyllanthus acuminatus Vahl. PLANTS (BASEL, SWITZERLAND) 2017; 6:E62. [PMID: 29244711 PMCID: PMC5750638 DOI: 10.3390/plants6040062] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/23/2022]
Abstract
The phenolic composition of leaves from Phyllanthus acuminatus L., a plant commonly used in Costa Rica as traditional medicine, was studied using UPLC-ESI-MS on an enriched phenolic extract. A total of 20 phenolic compounds were identified, comprising eight flavonoids (two flavanones-pinocembrin isomers and six derivatives from apigenin, chrysin, quercetin, and kaempferol); seven ellagitannins, two flavan-3-ols (prodelphinidin B dimer and (epi)gallocatechin); and three phenolic acids (ellagic acid, trimethylellagic acid, and ferulic acid). All of these compounds are reported for the first time in P. acuminatus, while previously reported in the genus Phyllanthus. Antioxidant evaluation was performed for P. acuminatus phenolic extract obtaining DPPH results with a remarkably low IC50 value of 0.15 μg/mL. Also, cytotoxicity on gastric AGS and colon SW20 adenocarcinoma cell lines was evaluated, and highly promising results were obtained, with IC50 values of 11.3 μg/mL and 10.5 μg/mL, respectively. Furthermore, selectivity index values obtained when comparing cytotoxicity on normal Vero cells was SI > 20 for both cancer cell lines, indicating a particularly high selectivity. Additionally, Justicidin B, a metabolite extensively studied for its antitumoral activity, was isolated from a non-polar extract of P. acuminatus, and comparatively evaluated for both bioactivities. The DPPH value obtained for Justicidin B was moderate (IC50 = 14.28 μg/mL), while cytotoxicity values for both AGS (IC50 = 19.5 μg/mL) and SW620 (IC50 = 24.8 μg/mL) cell lines, as well as selectivity when compared with normal Vero cells (SI = 5.4 and 4.2 respectively), was good, but lower than P. acuminatus extract. These preliminary results suggest that P. acuminatus enriched phenolic extract containing flavonoids, ellagitannins, flavan-3-ols, and phenolic acids, reported for the first time in this plant, could be of interest for further cancer cytotoxicity studies to elucidate structure-bioactivity relationships, and the molecular mechanisms and pathways.
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Affiliation(s)
- Mirtha Navarro
- Department of Chemistry, University of Costa Rica (UCR), Rodrigo Facio Campus, San Pedro Montes Oca, San Jose 2060, Costa Rica.
| | - Ileana Moreira
- Department of Biology, Technological University of Costa Rica (TEC), Cartago 7050, Costa Rica.
| | - Elizabeth Arnaez
- Department of Biology, Technological University of Costa Rica (TEC), Cartago 7050, Costa Rica.
| | - Silvia Quesada
- Department of Biochemistry, School of Medicine, University of Costa Rica (UCR), Rodrigo Facio Campus, San Pedro Montes Oca, San Jose 2060, Costa Rica.
| | - Gabriela Azofeifa
- Department of Biochemistry, School of Medicine, University of Costa Rica (UCR), Rodrigo Facio Campus, San Pedro Montes Oca, San Jose 2060, Costa Rica.
| | - Felipe Vargas
- Department of Chemistry, University of Costa Rica (UCR), Rodrigo Facio Campus, San Pedro Montes Oca, San Jose 2060, Costa Rica.
| | - Diego Alvarado
- Department of Biology, University of Costa Rica (UCR), Rodrigo Facio Campus, San Pedro Montes Oca, San Jose 2060, Costa Rica.
| | - Pei Chen
- Food Composition and Methods Development Laboratory, Department of Agriculture, Beltsville Human Nutrition Research Center, Agricultural Research Service, Beltsville, MD 20705, USA.
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Hemmati S, Seradj H. Justicidin B: A Promising Bioactive Lignan. Molecules 2016; 21:E820. [PMID: 27347906 PMCID: PMC6272961 DOI: 10.3390/molecules21070820] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 06/18/2016] [Accepted: 06/21/2016] [Indexed: 11/17/2022] Open
Abstract
Adverse effects and drug resistance to the current onchopharmacologicals have increased the demand for alternative novel therapeutics. We herein introduce justicidin B, an arylnaphthalen lignan isolated from different plant origins, especially Justicia, Phyllanthus, Haplophyllum and Linum species. This cyclolignan exhibits a wide array of biological properties ranges from piscicidal to antifungal, antiviral and antibacterial activities. Activity against Trypanosoma brucei makes justicidin B a potential antiprotozoal agent for the treatment of neglected tropical diseases. Pharmacological properties like antiplatelet, anti-inflammatory and bone resorption inhibition have been also attributed to justicidin B. This compound is a potent cytotoxic substance on several cell lines, especially chronic myeloid and chronic lymphoid leukemia. Pharmacological values, natural variation, as well as biotechnological production of justicidin B by plant cell, tissue and organ culture are also described in this review. Chemical characteristics and chromatographic methods to identify justicidin B and its biosynthetic pathway have been discussed. Different approaches to the total synthesis of justicidin B are compared. This review would shed light on the role of justicidin B as an intriguing natural compound and provides a chance to optimize conditions for industrial applications.
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Affiliation(s)
- Shiva Hemmati
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, P. O. Box 71345-1583 Shiraz, Iran.
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, P. O. Box 71345-3119 Shiraz, Iran.
| | - Hassan Seradj
- Department of Pharmacognosy, School of Pharmacy, Shiraz University of Medical Sciences, P. O. Box 71345-1583 Shiraz, Iran.
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Qi W, Hua L, Gao K. Chemical constituents of the plants from the genus Phyllanthus. Chem Biodivers 2014; 11:364-95. [PMID: 24634068 DOI: 10.1002/cbdv.201200244] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Indexed: 01/24/2023]
Affiliation(s)
- Weiyan Qi
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China
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Lv JJ, Yu S, Wang YF, Wang D, Zhu HT, Cheng RR, Yang CR, Xu M, Zhang YJ. Anti-hepatitis B virus norbisabolane sesquiterpenoids from Phyllanthus acidus and the establishment of their absolute configurations using theoretical calculations. J Org Chem 2014; 79:5432-47. [PMID: 24824117 DOI: 10.1021/jo5004604] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nineteen new highly oxygenated norbisabolane sesquiterpenoids, phyllanthacidoid acid methyl ester (1), and C-T (4-21), were isolated from Phyllanthus acidus Skeels, together with two known ones, phyllanthusols A (2) and B (3), whose sugar moiety was revised as glucosamine-N-acetate, rather than the previously assigned mannosamine-N-acetate. Compounds 2 and 3 were renamed respectively as phyllanthacidoids A (2) and B (3) to avoid confusion. All of the isolates except for 1 are glycosides, whose saccharide moieties possess a pentaoxy cyclohexane (scyllo quercitol) connecting with glucosamine-N-acetate or glucosyl moieties, which are first examples in natural products. Phyllanthacidoids N-R (15-19) with 8R configurations and/or 5,8-diketal skeleton, are unprecedented structures among norbisabolane sesquiterpenoids. Phyllanthacidoids S (20) and T (21) have the unusual tricyclo [3.1.1.1] oxygen bridge skeleton formed by a diketal system, of which the relative configurations of the aliphatic chain were assigned on the basis of heteronuclear coupling constants. The absolute configurations of compounds (1-21) were established by means of calculated electronic circular dichroism (ECD) and coupling constants. Compounds 1-5, 7-9, 10, and 14 displayed potential anti-hepatitis B virus (HBV) activities, with IC50 values of 0.8-36 μM against HBV surface antigen (HBsAg) and HBV excreted antigen (HBeAg), and the results indicated that the 5-ketal group and sugar moieties had contributions to the selectivity of HBsAg and HBeAg.
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Affiliation(s)
- Jun-Jiang Lv
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences , Kunming 650201, People's Republic of China
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Bates RW, Kasinathan S. Hydroformylation in Natural Product Synthesis. Top Curr Chem (Cham) 2013; 342:187-223. [DOI: 10.1007/128_2013_428] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Patel RM, Argade NP. Palladium-Promoted [2 + 2 + 2] Cocyclization of Arynes and Unsymmetrical Conjugated Dienes: Synthesis of Justicidin B and Retrojusticidin B. Org Lett 2012; 15:14-7. [DOI: 10.1021/ol3028658] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ramesh M. Patel
- Division of Organic Chemistry, National Chemical Laboratory (CSIR), Pune 411 008, India
| | - Narshinha P. Argade
- Division of Organic Chemistry, National Chemical Laboratory (CSIR), Pune 411 008, India
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Alonso F, Meléndez J, Soler T, Yus M. A direct synthesis of 1,7-dioxaspiro[4.5]decanes from the new 3-methylidenepentane-1,5-dianion synthon. Tetrahedron 2006. [DOI: 10.1016/j.tet.2005.12.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Flanagan SR, Harrowven DC, Bradley M. A new benzannulation reaction and its application in the multiple parallel synthesis of arylnaphthalene lignans. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00616-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bringmann G, Günther C, Ochse M, Schupp O, Tasler S. Biaryls in nature: a multi-facetted class of stereochemically, biosynthetically, and pharmacologically intriguing secondary metabolites. FORTSCHRITTE DER CHEMIE ORGANISCHER NATURSTOFFE = PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS. PROGRES DANS LA CHIMIE DES SUBSTANCES ORGANIQUES NATURELLES 2002; 82:1-249. [PMID: 11892255 DOI: 10.1007/978-3-7091-6227-9_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- G Bringmann
- Institut für Organische Chemie, Universität Würzburg, Germany.
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Zhang YJ, Tanaka T, Iwamoto Y, Yang CR, Kouno I. Novel sesquiterpenoids from the roots of Phyllanthus emblica. JOURNAL OF NATURAL PRODUCTS 2001; 64:870-873. [PMID: 11473414 DOI: 10.1021/np010059z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Three novel bisabolane-type sesquiterpenoids, phyllaemblic acids B (1) and C (2) and phyllaemblicin D (3), together with two new phenolic glycosides, 2-carboxylmethylphenol 1-O-beta-D-glucopyranoside (4) and 2,6-dimethoxy-4-(2-hydroxyethyl)phenol 1-O-beta-D-glucopyranoside (5), were isolated from the roots of Phyllanthus emblica. The structures of 1-5 were established by spectral and chemical methods. The absolute stereochemistry of 1 and 2 was determined by applying the PGME method.
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Affiliation(s)
- Y J Zhang
- Faculty of Pharmaceutical Sciences, Nagasaki University, Bunkyo-Machi 1-14, Nagasaki 852-8521, Japan
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Zhang YJ, Tanaka T, Iwamoto Y, Yang CR, Kouno I. Novel norsesquiterpenoids from the roots of Phyllanthus emblica. JOURNAL OF NATURAL PRODUCTS 2000; 63:1507-10. [PMID: 11087593 DOI: 10.1021/np000135i] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Three ester glycosides, named phyllaemblicins A (3), B (4), and C (5), and a methyl ester (2), of a highly oxygenated norbisabolane, phyllaemblic acid (1), were isolated from the roots of Phyllanthus emblica, along with 15 tannins and related compounds. The structures of 2-5 were established by spectral and chemical methods.
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Affiliation(s)
- Y J Zhang
- Faculty of Pharmaceutical Sciences, Nagasaki University, Bunkyo Machi 1-14, Nagasaki 852-8521, Japan
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Vongvanich N, Kittakoop P, Kramyu J, Tanticharoen M, Thebtaranonth Y. Phyllanthusols A and B, cytotoxic norbisabolane glycosides from Phyllanthus acidus Skeels. J Org Chem 2000; 65:5420-3. [PMID: 10993376 DOI: 10.1021/jo000439+] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N Vongvanich
- Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
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Zhang YJ, Tanaka T, Iwamoto Y, Yang CR, Kouno I. Phyllaemblic acid, a novel highly oxygenated norbisabolane from the roots of Phyllanthus emblica. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)00015-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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15
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Hitotsuyanagi Y, Fukuyo M, Tsuda K, Kobayashi M, Ozeki A, Itokawa H, Takeya K. 4-Aza-2,3-dehydro-4-deoxypodophyllotoxins: simple aza-podophyllotoxin analogues possessing potent cytotoxicity. Bioorg Med Chem Lett 2000; 10:315-7. [PMID: 10714489 DOI: 10.1016/s0960-894x(99)00693-9] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
4-Aza-2,3-dehydro-4-deoxypodophyllotoxin analogues 3a-n were synthesized through quinolines 2a-n. Comparison of their cytotoxicity against P-388 leukemia cells revealed that the steric effects of the ring B substituents on the activity are greater than the electronic effects, while the presence of a methoxy group on the ring E is not essential to exhibit potent cytotoxicity. Analogues 3a and 3b proved to be more than twice as cytotoxic as natural podophyllotoxin (1).
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Affiliation(s)
- Y Hitotsuyanagi
- Tokyo University of Pharmacy and Life Science, Hachioji, Japan
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Muñoz V, Sauvain M, Bourdy G, Callapa J, Rojas I, Vargas L, Tae A, Deharo E. The search for natural bioactive compounds through a multidisciplinary approach in Bolivia. Part II. Antimalarial activity of some plants used by Mosetene indians. JOURNAL OF ETHNOPHARMACOLOGY 2000; 69:139-155. [PMID: 10687870 DOI: 10.1016/s0378-8741(99)00096-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Forty-six different species collected in the Mosetene ethnia, dwelling in the Andean Piedmont of Bolivia, were screened for antimalarial properties. Thirty-three extracts were screened for antimalarial activity in vitro on Plasmodium falciparum chloroquine resistant strain (Indo), and forty-seven extracts were evaluated in vivo on the rodent malaria P. vinckei petteri 279BY. Only two plants are specifically used in combination by the Mosetene against malaria attack (Hymenachne donacifolia and Tesseria integrifolia), but they did not display any activity in vivo at 1000 mg/kg. The in vivo most active extracts were Swietenia macrophylla bark, Trema micrantha bark and Triplaris americana bark, not all of them were used for antimalarial purposes by the Mosetene. The following extracts were moderately active: Jacaratia digitata inner bark and Momordica charantia aerial part (both traditionally used as febrifuge), Kalanchoe pinnate aerial part (used in inflammatory processes), Lunania parviflora twigs and leaves, Phyllanthus acuminatus (used as piscicide), Tynanthus schumannianus fruit (used against diarrhoea), Triumfetta semitrilobata (used as febrifuge, to alleviate kidney and gynecological pain) and finally Solanum mammosum fruit (used against scabies). We present here the results of this screening, emphazing on the in vivo antimalarial activity of the selected plants. The antimalarial in vivo activity of the selected species, in relation with their traditional Mosetene use is then discussed.
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Affiliation(s)
- V Muñoz
- Instituto Boliviano de Biologia Andina, Casilla, La Paz, Bolivia
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Wender PA, Fuji M, Husfeld CO, Love JA. Rhodium-Catalyzed [5 + 2] Cycloadditions of Allenes and Vinylcyclopropanes: Asymmetric Total Synthesis of (+)-Dictamnol. Org Lett 1999. [DOI: 10.1021/ol990599b] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul A. Wender
- Department of Chemistry, Stanford University, Stanford, California, 94305-5080
| | - Masahiro Fuji
- Department of Chemistry, Stanford University, Stanford, California, 94305-5080
| | - Craig O. Husfeld
- Department of Chemistry, Stanford University, Stanford, California, 94305-5080
| | - Jennifer A. Love
- Department of Chemistry, Stanford University, Stanford, California, 94305-5080
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Calixto JB, Santos AR, Cechinel Filho V, Yunes RA. A review of the plants of the genus Phyllanthus: their chemistry, pharmacology, and therapeutic potential. Med Res Rev 1998; 18:225-58. [PMID: 9664291 DOI: 10.1002/(sici)1098-1128(199807)18:4<225::aid-med2>3.0.co;2-x] [Citation(s) in RCA: 278] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The plants of the genus Phyllanthus (Euphorbiaceae) are widely distributed in most tropical and subtropical countries, and have long been used in folk medicine to treat kidney and urinary bladder disturbances, intestinal infections, diabetes, and hepatitis B. In recent years, the interest in the plants has increased considerably. Substantial progress on their chemistal and pharmacological properties, as well as a few clinical studies of some Phyllanthus species have been made. This review discusses the current knowledge of their chemistry, the in vitro and in vivo pharmacological, biochemical, and clinical studies carried out on the extracts, and the main active constituents isolated from different species of plants of the genus Phyllanthus. These studies carried out with the extracts and purified compounds from these plants support most of their reported uses in folk medicine as an antiviral, in the treatment of genitourinary disorders, and as antinociceptive agents. However, well-controlled, double-binding clinical trials are lacking. Several compounds including alkaloids, flavonoids, lignans, phenols, and terpenes were isolated from these plants and some of them interact with most key enzymes. Together this data strongly supports the view that the plants belonging to the genus Phyllanthus have potential beneficial therapeutic actions in the management of hepatitis B, nefrolitiase, and in painful disorders.
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Affiliation(s)
- J B Calixto
- Department of Pharmacology, CCB, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil. calixto@a/farmaco.ufsc.br
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Pettit GR. Progress in the discovery of biosynthetic anticancer drugs. JOURNAL OF NATURAL PRODUCTS 1996; 59:812-821. [PMID: 8792630 DOI: 10.1021/np9604386] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- G R Pettit
- Department of Chemistry, Arizona State University, Tempe 85287-2404, USA
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Padwa A, Cochran JE, Kappe CO. Tandem Pummerer-Diels-Alder Reaction Sequence. A Novel Cascade Process for the Preparation of 1-Arylnaphthalene Lignans. J Org Chem 1996; 61:3706-3714. [PMID: 11667219 DOI: 10.1021/jo960295s] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The alpha-thiocarbocation generated from the Pummerer reaction of an o-benzoyl-substituted sulfoxide is intercepted by the adjacent keto group to produce an alpha-thio isobenzofuran as a transient intermediate which undergoes a subsequent Diels-Alder cycloaddition with added dienophiles. Acid-catalyzed ring-opening of the cycloadduct followed by aromatization gave an arylnaphthalene derivative. With acetylenic dienophiles, the tandem cyclization-cycloaddition sequence provided tetralones which result from a pinacol-type rearrangement of the primary cycloadducts. The versatility of the approach is highlighted through the synthesis of taiwanin C and E and justicidin E. The alpha-thiocarbocation generated from the Pummerer reaction of benzo[1,3]dioxol-5-yl-[6-[(ethylsulfinyl)methyl]benzo[1,3]dioxol-5-yl)methanone is intercepted by the adjacent keto group to produce an alpha-thioisobenzofuran as a transient intermediate which undergoes a subsequent Diels-Alder cycloaddition with dimethyl maleate. The initially formed Diels-Alder cycloadduct was readily converted to 5-benzo[1,3]dioxol-5-yl-8-(ethylthio)naphtho[2,3-d][1,3]dioxole-6,7-dicarboxylic acid dimethyl ester by loss of water on treatment with p-toluenesulfonic acid. Desulfurization of the thionaphthalene with Ra/Ni followed by hydrolysis of the less hindered methyl ester afforded 5-benzo[1,3]dioxol-5-ylnaphtho[2,3-d][1,3]dioxole-6,7-dicarboxylic acid 6-methyl ester which was further transformed into taiwanin C and justicidin E in good yield. Oxidation of the initial Diels-Alder cycloadduct with NaIO(4) in the presence of RuCl(3) followed by extrusion of ethyl sulfinate gave a naphthol derivative which can be converted into taiwanin E.
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Affiliation(s)
- Albert Padwa
- Department of Chemistry, Emory University, Atlanta, Georgia 30322
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21
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Reaction between piperidine-4-spiro-2?-oxiranes and nucleophilic reagents. Chem Heterocycl Compd (N Y) 1993. [DOI: 10.1007/bf00532027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Harrowven DC. Michael initiated ring closure reactions in natural product synthesis: a concise entry to the podophyllins. Tetrahedron 1993. [DOI: 10.1016/s0040-4020(01)91221-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Trost BM, Edstrom ED. Synthese von (+)-Phyllanthocin über eine metallkatalysierte Cycloreduktion. Angew Chem Int Ed Engl 1990. [DOI: 10.1002/ange.19901020509] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Phyllanthoside-Phyllanthostatin synthetic studies. 6. An augmented spiroketalization tactic for the total synthesis of phyllanthocin. Tetrahedron Lett 1989. [DOI: 10.1016/s0040-4039(00)70688-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Beecher CWW, Farnsworth NR, Gyllenhaal C. Pharmacologically Active Secondary Metabolites from Wood. ACTA ACUST UNITED AC 1989. [DOI: 10.1007/978-3-642-74075-6_31] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
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27
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Affiliation(s)
- G Cragg
- Natural Products Branch, National Cancer Institute, Bethesda, Maryland 20892
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Burke SD, Cobb JE. Intramolecular phosphine-directed hydroformylation. Application to the total synthesis of (+)-phyllanthocin. Tetrahedron Lett 1986. [DOI: 10.1016/s0040-4039(00)94241-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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A new route to 1-phenylnaphthalenes by cycloaddition: a simple and selective synthesis of some naphthalene lignan lactones. Tetrahedron Lett 1985. [DOI: 10.1016/s0040-4039(00)98577-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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