- EPI-ISOSHINANOLONE FROM PLUMBAGO SCANDENS
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Epi-isoshinanolone, a diastereomer of isoshinanolone, has been isolated from Plumbago scandens and characterized with the aid of NMR spectroscopy.Key Word Index - Plumbago scandens; Plumbaginaceae; epi-isoshinanolone; plumbagin; 13C NMR.
- Bhattacharyya, J.,Carvalho, Vicente R. de
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- Axially Chiral Dimeric Naphthalene and Naphthoquinone Metabolites, from Root Cultures of the West African Liana Triphyophyllum peltatum
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Root cultures of the West African liana Triphyophyllum peltatum were initiated from stem explants of in vitro cultivated shoots. From these organ cultures, three new binaphthalenes, one binaphthoquinone, and two (bi)naphthalene glucosides were isolated, with substitution patterns related to those of the naphthylisoquinoline alkaloids, which are the normal main metabolites of T. peltatum. The structures of the diglucoside dioncoquinoside A (1) and of the axially chiral biaryls triphyoquinols A1 (3), A2 (4), and B (5), triphyoquinoside A (6), and triphyoquinone A (7) were elucidated by spectroscopic analysis (HRESIMS, 1D and 2D NMR) and by application of electronic circular dichroism (ECD) spectroscopy in combination with the exciton chirality method and quantum-chemical ECD calculations. The root cultures likewise produced the known alkaloids dioncophylline A (8), 5′-O-demethyldioncophylline A (9), dioncopeltine A (10), habropetaline A (11), and 5′-O-methyldioncophylline D (12a/b), the naphthalene glucoside plumbaside A (2), and the naphthoquinones plumbagin (13), droserone (14), and 8-hydroxydroserone (15).
- Bringmann, Gerhard,Irmer, Andreas,Büttner, Tobias,Schauml?ffel, Anu,Zhang, Guoliang,Seupel, Raina,Feineis, Doris,Fester, Karin
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- QUINONOID AND OTHER CONSTITUENTS OF ARISTEA ECKLONII
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Aristea ecklonii; Iridaceae; quinones; plumbagin; biplumbagin; neoisoshinanolone; sterols.Plumbagin, 3,3'-biplumbagin, 8,8'-biplumbagin, neoisoshinanolone and sitosterol were isolated from the leaves and rhizomes of Aristea ecklonii.The rhizomes also contained α-spinasterol.This is the first report of plumbagin, previously found in several dicotyledonous families, in a monocotyledon.
- Kumar, Vijaya,Meepagala, Kumudini M.,Balasubramaniam, Sinnathamby
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- NAPHTHOQUINONES AND TRITERPENES FROM SOME ASIAN DIOSPYROS SPECIES
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Investigation of the stem bark, wood and/or fruit of nine Asian Diospyros spp. (Ebenaceae) has revealed a range ot triterpenes and naphthoquinones typical of the genus.In addition to lupeol, betulin and betulinic acid, which were present in all samples, seven other triterpenes were isolated and identified.Six of the nine species also yielded naphthoquinones.In two species these were based on 2-methyljuglone (plumbagin) and in the other four on 7-methyljuglone.Key Word Index -- Diospyros spp; Ebenaceae; simple and dimeric naphthoquinones; triterpenes; oleanane-type; ursane-type.
- Zakaria, Muhamad Bin,Jeffreys, J. A. D.,Waterman, Peter G.,Zhong, Shou-Ming
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- ISOLATION AND STRUCTURES OF DIOMUSCINONE AND DIOMUSCIPULONE FROM DIONAEA MUSCIPULA
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From the fresh leaves and roots of Dionaea muscipula, two new substances (diomuscinone and diomuscipulone) have been isolated together with the known naphthoquinone plumbagin.The structures of the new compounds have been elucidated on the basis of their spectral data coupled with some chemical evidence. - Key Word Index: Dionaea muscipula; Droseraceae; phenolic compounds; diomuscinone; diomuscipulone.
- Miyoshi, Eiichi,Shizuri, Yoshikazu,Yamamura, Shosuke
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- 1,4-Naphthoquinones, XXIV: On the dehalogenation of 2-/3-halogen-1,4-naphthoquinone derivatives
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Bu3SnH is an effective reagent for the debromination of 2-bromonaphthoquinones but elimination of chlorine with 1c, e.g., only proceeds at 30%. With Et3SiH dechlorination does not occur at all. Instead, with the 5-acetoxy derivatives 1a/1d as starting materials the cyclic acetales 3a-c are formed as selectively protected juglone derivatives. The bromo derivative 3a is obtained only at temp. 10° and even at room temp. Br-Elimination occurs with low yield of 3b. An especially suitable reagent for the debromination of 1a-b leading to the natural compounds plumbagin (2a) and isoplumbagin (2b) is zinc-silver couple but Cl-elimination again occurs in traces only.
- Wurm,Duchstein
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- Mechanism of Conjugate Additions of Dialkylcuprates to Bromonaphthoquinones
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The correlation of bromonaphthoquinone redox potentials with reactivity toward dialkylcuprates reveals that the conjugate addition of Gilman reagents to bromojuglones proceeds via a single-electron-transfer mechanism.
- Wigal, Carl T.,Grunwell, John R.,Hershberger, James
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- Enantioselective Nickel-Catalyzed Reductive Aryl/Alkenyl-Cyano Cyclization Coupling to All-Carbon Quaternary Stereocenters
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An enantioselective nickel-catalyzed intramolecular reductive cross-coupling of C(sp2) electrophiles and cyano groups is reported. Enantioenriched CN-containing all-carbon quaternary stereocenters are assembled by desymmetrizing cyclization of aryl/alkeny
- Chen, Zi-Hao,Sun, Rui-Ze,Yao, Fei,Hu, Xu-Dong,Xiang, Long-Xue,Cong, Hengjiang,Liu, Wen-Bo
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supporting information
p. 4776 - 4782
(2022/03/27)
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- Catalyst-Controlled Transannular Polyketide Cyclization Cascades: Selective Folding of Macrocyclic Polyketides
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The biomimetic synthesis of aromatic polyketides from macrocyclic substrates by means of catalyst-controlled transannular cyclization cascades is described. The macrocyclic substrates, which feature increased stability and fewer conformational states, were thereby transformed into several distinct polyketide scaffolds. The catalyst-controlled transannular cyclizations selectively led to aromatic polyketides with a defined folding and oxygenation pattern, thus emulating β-keto-processing steps of polyketide biosynthesis.
- Raps, Felix C.,F?seke, Vincent C.,H?ussinger, Daniel,Sparr, Christof
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supporting information
p. 18390 - 18394
(2020/08/25)
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- Ruthenium-catalyzed C-H oxygenation of quinones by weak O-coordination for potent trypanocidal agents
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Ruthenium-catalysis enabled the C-5 selective C-H oxygenation of naphthoquinones, and also sets the stage for the site-selective introduction of a hydroxyl group into anthraquinones. A-ring modified naphthoquinoidal compounds represent an important class of bioactive quinones for which the present study encompasses the first C-H oxygenation strategy by weak O-coordination.
- Dias, Gleiston G.,Rogge, Torben,Kuniyil, Rositha,Jacob, Claus,Menna-Barreto, Rubem F. S.,Da Silva Júnior, Eufranio N.,Ackermann, Lutz
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supporting information
p. 12840 - 12843
(2018/11/30)
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- Highly Efficient Synthesis and Structure–Activity Relationships of a Small Library of Substituted 1,4-Naphthoquinones
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A platform of highly efficient synthetic methodologies has been established to access a focused library of substituted 1,4-naphthoquinones derivatives functionalized with a diversity of amino/hydroxy/alkyl groups. Furthermore, the structure–activity relationship deduced from antiproliferative activities and toxicities of this 1,4-naphthoquinone library and intracellular reactive oxygen species (ROS) level detections might warrant future potential of plumbagin (2) and compound 13 as promising basic structures to develop novel anti-cancer agents.
- Bao, Na,Ou, Jinfeng,Shi, Wei,Li, Na,Chen, Li,Sun, Jianbo
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p. 2254 - 2258
(2018/06/04)
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- New synthetic method of plumbagin
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The invention discloses a new synthetic method of plumbagin (PL), and relates to the technical field of medicine and chemical industry. The plumbagin becomes a study hot spot in treating rheumatoid arthritis and other domains. In recent years, literatures report that the plumbagin also has the effects of preventing bacterial and fungal and is used for the study of anticancer and anti-AIDS infection. However, the extraction rate of nature plumbagin is low, and the profit space is small; besides, the reported synthetic method of plumbagin is low in overall yield, high in cost, and not easy to acquire the raw material reagent, complex in post treatment process, and not friendly for environment; moreover, the purification process involves in column chromatography for many times. The raw material for the synthetic method of plumbagin is low in price and easy to acquire, and environment-friendly; the post treatment and purification process are simple, the yield is greatly promoted, the industrial production can be realized; meanwhile, the method provides an important reference basis for the subsequent scientific and research work.
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- A rapid, solvent-free deprotection of methoxymethyl (MOM) ethers by pTSA; An eco-friendly approach
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Background: Ease of preparation and alkaline stability of methoxymethyl (MOM) makes it an important hydroxyl protecting group. A number of methods are available for the deprotection of MOM. Though the methods are good in general, they use solvents, require prolonged reaction time and tedious work up. A solvent free, solid phase, fast deprotection of MOM has been developed and is the major theme of this paper. Methods: A mixture of MOM protected compounds and pTSA is triturated in a mortar (5 min) and left at room temperature for 30 min. On addition of water (4°C), pTSA, methanol and formaldehyde dissolved leaving the products as precipitates. Results: A series of different MOM ethers were deprotected by this method in good to excellent yield (85-98%). The compatibility of MOM in the presence of other protections such as methoxyl, benzyl, ester, amide, allyl and lactone was also established. Acetate protection is not stable under these conditions. Conclusion: An efficient, selective and high yielding deprotection MOM groups by pTSA under solvent free condition is described. The process is environment friendly since no solvent was used in the deprotection process. The reaction conditions are mild and should be useful for the deprotection of MOM derivatives of complex and labile molecules.
- Pandurangan, Nanjan
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p. 231 - 235
(2017/07/15)
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- Effective one-pot synthesis of 5-hydroxy-1,4-naphthoquinone derivatives
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In the presence of triethylamine, Diels-Alder reaction, involving decarboxylation-oxidation reaction of 3-hydroxy-2-pyrones with 1,4-benzoquinones gave 5-hydroxy-1,4-naphthoquinone derivatives in excellent to reasonable yields. Georg Thieme Verlag Stuttgart.
- Komiyama, Takuzo,Takaguchi, Yutaka,Tsuboi, Sadao
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p. 1405 - 1407
(2007/10/03)
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- Oxidative coupling of methoxynaphthylenediols
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The oxidative coupling of a mixture of 1-methoxy-7-methyl-4,5- naphthylenediol and 4-methoxy-7-methyl-1,5-naphthylenediol using lead(IV) oxide gives the symmetrical bisnaphthalene indigos diosindigo A and diosindigo B together with the corresponding unsymmetrical isomer. Oxidation of the first two by nitric acid gives the binaphthyldiquinones mamegakinone and biramentaceone, respectively; the third gives the unsymmetrical diquinone rotundiquinone. Similar oxidations of related naphthylenediols are described.
- Maiti, Bhim C.,Musgrave, Oliver C.,Skoyles, Douglas
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p. 6568 - 6574
(2007/10/03)
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- Synthesis of antibiotics WS 5995 A and C and related compounds by palladium-catalyzed coupling of 2-bromonaphthoquinones with organostannanes
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The synthesis of arylnaphthoquinones can be performed simply by using as the key reaction the Pd(0)- and Cu(I)-catalyzed coupling of arylstannanes with 2-bromonaphthoquinones as the electrophiles. The palladium-catalyzed coupling reaction is general and allows for the functionalization of the unprotected quinone nucleus with alkyl, alkenyl, and aryl substituents. The coupling process tolerates the presence of a chelated peri hydroxyl and steric crowding of a 2,6-disubstituted arylstannane, although the preparation of a 2,6,2',6'-tetrasubstituted biaryl by coupling of 2-bromo-3,5-bis(acetyloxy)-1,4-naphthoquinone as the electrophile with 2,6-disubstituted arylstannanes was unsuccessful. The syntheses of quinonoid antibiotics WS 5995 A and C was accomplished by using this method as the key step. Benz[b]phenanthridinone 1, hypothetical intermediate in the biosynthesis of benz[b]phenanthridine alkaloids, was also prepared from antibiotic WS 5995 C or by addition of ammonia to the 2-aryl-1,4-naphthoquinone 41 followed by heterocyclization.
- Echavarren,Tamayo,Cardenas
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p. 6075 - 6083
(2007/10/02)
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- Method for dyeing keratinous fibres using a monohydroxyindole or dihydroxyindole and a non-oxidizing aromatic carbonyl derivative and dyeing agent
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The present invention relates to a method for dyeing keratinous fibers, characterized in that the following are applied to the fibers: a) a composition (A) containing, in a medium appropriate for dyeing, at least one monohydroxyindole or dihydroxyindole, this application being preceded or followed by the application of b) a composition (B) containing, in a medium appropriate for dyeing, at least one aromatic carbonyl derivative chosen from hydroxyacetophenones, hydroxybenzophenones, 2-hydroxy-1,4-benzoquinones, hydroxy-1,4-naphthoquinones,amino-1,4-naphthoquinones,hydroxy-9,10-anthraquinones and amino-9,10-anthraquinones. It also relates to the dyeing agents for carrying it out.
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- Regiospecific Addition of Monooxygenated Dienes to Halo Quinones
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In spite of their decreased polarity with respect to previously studied electron-rich analogues, monooxygenated dienes also react regiospecifically with halo quinones.The corresponding adducts can easily be aromatized on silica gel to isomeric polysubstituted naphthoquinones of unambiguous structure and therefore provide ready access to substrates for subsequent regiospecific annulations.The scope of this approach is illustrated by advantageous syntheses of several natural products: chimaphilin, 6-methylalizarin, 6-methylxantopurpurin, and barleriaquinone.The adductscan also give rise to a series of products in which the oxygen function of the dienes is preserved as a hydroxyl group in the quinone.To this end adducts derived from 1-oxygenated dienes and halo quinones were oxidized effectively with Jones reagent while those obtained from the 2-oxygenated isomers responded better to manganese dioxide.Relative positions of substituens in the adducts were readily confirmed by comparison of some of the hydroxylated oxidation products with known compounds of unambiguous structure.The method is again illustrated by the ready synthesis of a number of natural products including plumbagin, soranjidiol, isochrysophanol and its 8-methyl ether, and isozyganein and its 5-methyl ether.
- Boisvert, Louise,Brassard, Paul
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p. 4052 - 4059
(2007/10/02)
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- A REVISED STRUCTURE FOR PLUMBAZEYLANONE
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The structure of plumbazeylanone has been revised, by X-ray crystallography, to 1,2,3,4-tetrahydro-5-hydroxy-1,4-diketo-2-methyl-2,3-di(5'-hydroxy-2'-methyl-1,4-naphthoquinon-3'-yl)naphthalene.
- Gunaherath, G. M. Kamal B.,Gunatilaka, A. A. Leslie,Cox, Philip J.,Howie, R. Alan,Thomson, Ronald H.
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p. 719 - 720
(2007/10/02)
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- Model Reactions for Plumbagin Synthesis, 2nd Communication. 5-Amino-1-naphthol as Starting Compound
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The aminomethylation of 5-amino-1-naphthol (1) and 5-acetamido-1-naphthol (9) is examined.While the hydrogenolysis of the phenol Mannich bases derived from 1 cannot be accomplished, the derivatives of 9 react easily.The oxidation of the 2-methylphenol compounds 5 and 18 to the corresponding quinones may performed with Fremy's salt.The following transforming of the amino to the hydroxy group by nitrosylsulfuric acid succeeds with small yield only. - Keywords: Aminoalkylation, Hydrogenolysis, Phenoloxidations, Aminoquinones
- Moehrle, Hans,Folttmann, Hubertus
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p. 1578 - 1584
(2007/10/02)
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- Dimeric Naphthoquinones, IX. - Isodiospyrin and Elliptinone. - Synthesis of 6,6'-Dimeric Bijuglones by Phenol Oxidation
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Oxidative coupling of the naphthol 37a gave the potential natural product 7,7'-dimethyl-6,6'-bijuglone (5) and, in lower yield, isodiospyrin (21).Regiospecific syntheses of 5, elliptinone (10), and 6,6'-bijuglone (45a) were achieved by phenol oxidation of suitable substituted p-chloronaphthols.
- Laatsch, Hartmut
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p. 319 - 339
(2007/10/02)
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- 1,2(3)-TETRAHYDRO-3,3'-BIPLUMBAGIN: A NAPHTHALENONE AND OTHER CONSTITUENTS FROM PLUMBAGO ZEYLANICA
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The isolation of plumbagin, droserone, isoshinanolone and a new naphthalenone, 1,2(3)-tetrahydro-3,3'-biplumbagin is reported from the phenolic fraction of the lightpetrol extract of the roots of Plumbago zeylanica.The structure of the new naphthalenone was elucidated by means of spectroscopic data and chemical interconversions.The main constituent of the neutral fraction was shown to be sitosterol. - Key Words: Plumbago zeylanica; Plumbaginaceae; plumbagin; droserone; isoshinanolone; naphthalenones; 1,2(3)-tetrahydro-3,3'-biplumbagin; sitosterol; structure elucidation.
- Gunaherath, G.M.Kamal B.,Gunatilaka, A.A.Leslie,Sultanbawa, M. Uvais S.,Balasubramaniam, S.
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p. 1245 - 1248
(2007/10/02)
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