Phloroglucinol compounds of natural origin

A highly stereoselective asymmetric synthesis of (--)-sedamine and (--)-lobeline is described from benzaldehyde in 16 and 17 steps with an overall yield of 20% and 14%, respectively. The key intermediate syn-3,4-epoxyalcohol was prepared in a highly diastereomeric fashion (>99% ee, dr) and served as a common intermediate for both alkaloids.

A highly stereoselective asymmetric synthesis of (--)-lobeline and (--)-sedamine.

In recent years a widespread interest in the antidepressant activity of Hypericum perforatum L. has attracted much activity in investigating metabolites from the Guttiferae, many of which are biologically active compounds with an acylphloroglucinol moiety. A common background in the traditional uses of plants belonging to Guttiferae family is their wound healing properties which has been connected to the established antimicrobial activities of the phloroglucinols present. These metabolites share a common acylated 1,3,5-trihydroxy-benzene core of polyketide origin which undergoes alkylation processes. Polycyclic polyprenylated acylphloroglucinols feature a highly oxygenated and densely substituted bicyclo[3.3.1]nonane-1,3,5-trione core appended with prenyl or geranyl side chains. Secondary cyclizations involve the β-diketone and pendant olefinic groups affording adamantanes, homoadamantanes, dihydrofurano- or pyrano- fused structures. These products are claimed to possess antioxidative, antiviral and antimitotic properties. Increasing interest is related to their function in the CNS as modulators of neurotransmitters associated with neuronal damage and depression.

Are acylphloroglucinols lead structures for the treatment of degenerative diseases

1. Anti-Inflammatory Plants 1.1. General Concept 1.2. Inhibitors of Phospholipase A2 Medicinal Aristolochiaceae Aristolochia indica L. Aristolochia kaempferi Willd. Aristolochia recurvilabra Hance Thottea grandiflora Rottb. Medicinal Myristicaceae Horsfieldia amygdalinia (Wall.) Warb. Horsfieldia valida (Miq.) Warb. Medicinal Caprifoliaceae Lonicera japonica Thunb. Sambucus javanica Reinw. ex Bl. Weigela floribunda (Sieb. & Zucc.) K. Koch. Medicinal Asteraceae Cirsium japonicum DC Crossotephium chinense L. 1.3. Inhibitors of Cyclooxygenase Medicinal Apocynaceae Trachelospermum asiaticum (Sieb. & Zucc.) Nak. Medicinal Clusiaceae Garcinia atroviridis Griff. Medicinal Asteraceae Chrysanthemum sinense Sab. Medicinal Polygonaceae Polygonum amphibium L. Medicinal Lamiaceae Ocimum basilicum L. Glechoma brevituba Kuprian 1.4. Inhibitors of Lipoxygenases Medicinal Myrsinaceae Ardisia villosa Roxb. Medicinal Clusiaceae Hypericum erectum Thunb. Medicinal Asteraceae Medicinal Apiaceae Bupleurum chinense DC 1.5. Inhibitors of Elastase Medicinal Asteraceae Sigesbeckia orientalis L. Sigesbeckia glabrescens Mak Mikania cordata (Burm.f.) B.L. Robinson Medicinal Droseraceae Drosera rotundifolia L. 1.6. Inhibitors of Nitric Oxide Synthetase Medicinal Asteraceae Inula chinensis Rupr. ex Maxim. Carpesium divaricatum Sieb. et Zucc Medicinal Lauraceae Neolitsea zeylanica Nees (Merr.) (Tetradenia Litsea cubeba (Lour.) Pers. Litsea odorifera Val. Medicinal Solanaceae Physalis alkekengi L. 1.7. Conclusion and Future Prospects 1.8. References 2. Plant Affecting the Central Nervous System 2.1. General Concept 2.2. Plants Affecting the Serotoninergic Neurotransmission Medicinal Annonaceae Fissistigma lanuginosum (Hook.f. & Thoms.) Merr. Cyathostemma micranthum (A. DC.) J. Sinclair. Medicinal Myristicaceae Horsfieldia glabra (Bl.) Warb. Medicinal Convolvulaceae Ipomoea obscura (L.) Ker-Gawl. Ipomoea digitata L. Ipomoea indica Merr. Medicinal Apocynaceae Ervatamia pandacaqui (Poir.) Pichon Ervatamia corymbosa (Roxb.) King & Gamble Medicinal Zygophyllaceae Tribulus terrestris L. Medicinal Polygalaceae Polygala tenuifolia Polygala japonica Houtt. Polygala glomerata Lour. Medicinal Rubiaceae Psychotria adenophylla Wall. Rubia cordifolia L. Uncaria rhynchophylla Miq. 2.3. Plants Affecting the GABAergic Neurotransmission Medicinal Valerianaceae Nardostachys chinensis L. Nardostachys jatamansi DC. Patrinia scabiosaefolia Link Medicinal lamiaceae Scutellaria baicalensis Georgi Leonotis nepetifolia R.Br Medicinal Asteraceae Artemisia stelleriana Bess. Medicinal Orchidaceae Gastrodia elata Bl. Acriopsis javanica Reinw. Bulbophyllum vaginatum Reich. f. Calanthe triplicata (Villem.) Ames Calanthe vestita Lindl. Dendrobium crumenatum Sw. 2.4. Plants Interfering with the Glycinergic System Medicinal Loganiaceae Strychnos ignatii Berg. Strychnos minor Dennst. Strychnos axillaris Colebr. Medicinal Apocynaceae 2.5. Plants Affecting the Dopaminergic Neurotransmission Medicinal Araliaceae Acanthopanax gracilistylus W. W. Sm. Acanthopanax trifoliatus (L.) Merr. Acanthopanax ricinifolius Seeman Medicinal Verbenaceae Vitex negundo L. Vitex trifolia L Vitex quinata (Lour.) F.N. Will. Vitex vestita Wallich ex Schauer Medicinal Sapindaceae Erioglossum rubiginosum (Roxb.) Bl. Sapindus mukorossi Gaertn Dodonaea viscosa (L.) Jacq. Medicinal Celastraceae Tripterygium wilfordii Hook f Medicinal Lauraceae Cassytha filiformis L. Cryptocarya griffithiana Wight Medicinal Ranunculaceae Aconitum fischeri Reichb Coptis teeta Wall. Cimicifuga foetida L. Medicinal Menispermaceae Stephania cepharantha Hayata 2.6. Conclusion and Future Prospect 2.7. References 3. Plants for Chemotherapy of Neoplastic Diseases 3.1. General Concept 3.2. Topoisomerase Inhibitors Medicinal Annonaceae Artabotrys suaveolens Bl. Fissistigma fulgens (Hk. f. et Th.) Merr. Friesodielsia latifolia Hk. f. et Th. Medicinal Lauraceae Persea thunbergii (Sieb. & Zucc.) Kosterm. Lindera tzumu Hemsl. Cassytha filiformis L. Medicinal Hernandiaceae Illigera luzonensis L. Medicinal Ebenaceae Diospyros sumatrana Miq. Diospyros toposioides King & Gamble Medicinal Rubiaceae Prismatomeris albiflora Thaw, non King Knoxia valerianoide Thorel Damnacanthus indicus Gaertn. Neonauclea pallida (Reinw. ex Havil.) Bakh f. Morinda officinalis How Medicinal Rutaceae Zanthoxylum ailanthoides Sieb. & Zucc. Zanthoxylum bungei Planch. Zanthoxylum piperitum (L.) DC. Zanthoxylum schinifolium Zieb. & Zucc. Medicinal Euphorbiaceae Alchornea villosa (Benth.) Muell. - Arg. Alchornea rugosa (Lour.) Muell. Arg Phyllanthus acidus (L.) Skeels Macaranga triloba (Reinw.) Muell.-Arg. Medicinal Hamamelidaceae Altingia excelsa Noronha Medicinal Lamiaceae Salvia plebeia R.Br. Salvia japonica Thunb. Salvia miltiorrhiza Bunge 3.3. Apoptosis Medicinal Annonaceae Goniothalamus species Pseudouvaria setosa (King) J. Sinclair Medicinal Asteraceae Elephantopus mollis Kunth Blumea riparia (Bl.) DC. Spilanthes paniculata Wall. ex DC Lactuca indica L. 3.4. Summary and Future Prospects 3.5. References

Ethnopharmacology of Medicinal Plants: Asia and the Pacific

The stereodivergent construction of cyclic ethers remains an important area of synthetic interest, particularly given the ubiquity of C-glycoside derivatives in natural and unnatural pharmacologically important agents. This work describes a series of intramolecular etherification reactions of δ-trialkylsilyloxy aldehydes and ketones using catalytic bismuth tribromide and various trialkylsilyl nucleophiles for the construction of cis- and trans-2,6-di- and trisubstituted tetrahydropyrans. Furthermore, this study provides compelling evidence for the fact that the catalysis may be attributed to the hydrogen bromide and bismuth oxybromide derived from the hydrolysis of bismuth tribromide. The synthetic utility of this protocol is highlighted in the ability to construct adjacent tertiary ethers in a highly stereoselective manner and the development of a sequential two-component cross-coupling followed by reductive etherification process for the expeditious synthesis of nonadjacent tetrahydropyran rings.

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Stereoselective construction of cyclic ethers using a tandem two-component etherification: elucidation of the role of bismuth tribromide.

Benzopyran derivatives from Mallotus apelta

Polyprenylated phloroglucinol derivatives from Hypericum erectum

Erectones A and B, two dome-shaped polyprenylated phloroglucinol derivatives, from Hypericum erectum

Two new benzopyran derivatives from Mallotus apelta.

Examination of the whole plant of the Chinese herbal medicine Hypericum erectum yielded two novel metabolites, erectones A and B (1 and 2), which were characterized by their 2,2a,3,3a,6,6a,8b,8c-octahydro-1-oxa-cyclopenta[bc]acenaphthylen-7-one cores with isoprenyl and geranyl substituents. Their structures were established using extensive spectroscopic methods.

Tian-Ying An

Papers

Benzopyran derivatives from Mallotus apelta

Polyprenylated phloroglucinol derivatives from Hypericum erectum

Erectones A and B, two dome-shaped polyprenylated phloroglucinol derivatives, from Hypericum erectum

Two new benzopyran derivatives from Mallotus apelta.

Erectones A and B, Two Dome-Shaped Polyprenylated Phloroglucinol Derivatives, from Hypericum erectum.