A New Approach to Sesquiterpene Arenes of the 9,11‐Drimenyl Type (= [(1E,2RS,4aRS,8aRS)‐Octahydro‐2,5,5,8a‐tetramethylnaphthalen‐1(2H)‐ylidene] methyl Type)

A new reaction sequence for the synthesis of the sesquiterpene arenes (±)‐wiedendiol B ((±)‐ 1 ) and the siphonodictyal B derivative (±)‐ 21 consists in the coupling of (±)‐drimanoyl chloride ((±)‐ 3 ) with lithiated and appropriately substituted aromatic synthons to furnish the ketones (±)‐ 7 and (±)‐ 17 which were reduced to the benzyl alcohols (±)‐ 8a,b and (±)‐ 18a,b , respectively (Schemes 5, 4, and 12). The 9,11‐double bond of the drimenes (±)‐ 9 and (±)‐ 19 was formed by elimination of H₂O from the benzyl alcohols (±)‐ 8a,b and (±)‐ 18a,b (Schemes 6 and 12). New alternatives were applied to this elimination reaction involving either the pyridine ? SO₃ complex or chloral as reagents.     

The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C(18) dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C(19) homolignan named schiarisanrin E (5), together with the known C(18) lignans, gomisin B (6), G (7) and (+)-gomisin K(3) (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K(3) showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.     

Phenolic glycosides and pyrrolidine alkaloids from Codonopsis tangshen

Chemical examination of the n-butanol extract of the root of Codonopsis tangshen led to the isolation of four new compounds named codonosides A (1) and B (2) and codonopyrrolidiums A (3) and B (4), with seven known compounds [(Z)-2-(beta-glucopyranosyloxy)-3-phenylpropenoic acid (5), lobetyolin (6), lobetyol (7), luteolin (8), friedelin (9), 5,6,9-trihydroxy-octadec-7-enoic acid (10), and adenosine (11)]. Based on spectroscopic evidence, the structures of codonosides A (1) and B (2) were established as phenolic glycosides, and those of codonopyrrolidiums A (3) and B (4) as pyrrolidines. The relative configuration of 3 was determined by X-ray crystallographic analysis.     

Two diterpene rhamnosides, mimosasides B and C, from Mimosa hostilis

Two new diterpene rhamnosides, mimosasides B and C (1, 2) were isolated together with mimosaside A (3), a known diterpene rhamnoside (4), four known flavones (5-8), five known flavanones (9-13), and four known chalcones (14-17) from the leaves and twigs of a Brazilian medicinal plant, Mimosa hostilis.     

Prepatellamide A, a new cyclic peptide from the ascidian Lissoclinum patella

A new cyclic peptide, prepatellamide A (1), along with three known cyclic peptides (2)-(4), was isolated from the ascidian Lissodinum patella. The structure of prepatellamide A was determined from one- and two-dimensional H and 13C NMR spectra. The known cyclic peptides were identified as patellamides A (2), B (3) and C (4).     

Antimitotic and antifungal C-3/C-3''-biflavanones from Stellera chamaejasme

Two new C-3/C-3' biflavanones, chamaejasmenin D (1) and isochamaejasmenin B (2), were isolated from the roots of Stellera chamaejasme, together with five known biflavanones, chamaejasmenin A (3), chamaejasmenin B (4), neochamaejasmin A (5), sikokianin A (6), and chamaejasmenin C (7). Their structures were elucidated by spectroscopic methods, including 2D NMR techniques. Among these compounds, 1-3 demonstrated potent antimitotic and antifungal activity with minimum inhibitory concentration (MIC) values of 6.25, 6.25, and 3.12 microg/ml, respectively.     

A New Eremophilane Sesquiterpene from Cultures of the Fungus Pholiota nameko

Chemistry of Natural Compounds - A new eremophilane sesquiterpene (1), together with four known sesquiterpenes, donacinol B (2), donacinol C (3), trichapargin A (4), and trichapargin B (5), were...     

Two new dioxopiperazine derivatives, arestrictins A and B, isolated from Aspergillus restrictus and Aspergillus penicilloides

In the course of searching for bioactive substances, two new dioxopiperazine derivatives, arestrictins A (1) and B (2), were isolated along with the known dioxopiperazine, cristatin A (3), and the known peptide, asperglucide (4), from the organic extract of the xerophilic fungi, Aspergillus restrictus and Aspergillus penicilloides. The absolute structures of 1 and 2, except for the configuration of the secondary alcohol in 1, were established by spectroscopic and chemical investigation. The absolute configuration of cristatin A (3) was also determined.     

Neoclerodanes from Teucrium orientale

Two new neoclerodane diterpenoids, 6-deacetyl-teucrolivin A (5) and 8beta-hydroxy-teucrolivin B (6), were isolated from the aerial parts of Teucrium orientale, along with four already known neoclerodane diterpenoids, teucrolivin A (1), teucrolivin B (2), teucrolivin C (3) and teucrolivin H (4), previously isolated from Teucrium oliverianum. Their structures were elucidated on the basis of spectroscopic evidence and chemical transformations. Compounds 1-3 were assayed for antifeedant activity against Spodoptera littoralis, S. frugiperda and Heliocoverpa armigera. Teucrolivin A was the most potent of the three compounds tested.     

New iridoid glucosides from the aerial parts of Verbena brasiliensis

Two new iridoid glucosides, verbenabraside A (1) and verbenabraside B (2), were isolated from the aerial parts of Verbena brasiliensis VELL., along with six known iridoid glucosides, gelsemiol 3-O-beta-D-glucoside (3), verbraside (4), 9-hydroxysemperoside (5), griselinoside (6), aralidioside (7), and 6alpha-hydroxyforsythide dimethyl ester (8), three known phenylethanoid glycosides, 2-phenylethyl O-beta-D-xylopyranosyl-(1-->2)-beta-D-glucopyranoside (9), acteoside (10), and leucosceptoside A (11), two known lignan glucosides, dihydroxymethyl-bis(3,5-dimethoxy-4-hydroxyphenyl) tetrahydrofuran-9 (or 9')-O-beta-glucopyranoside (12) and (+)-lyoniresinol 3alpha-O-beta-D-glucopyranoside (13), a known methyl salicylate glucoside, methyl 2-O-beta-D-glucopyranosylbenzoate (14), and two known sterols, beta-sitosterol 3-O-beta-D-glucopyranoside (15) and beta-sitosterol (16). Their chemical structures were determined on the basis of spectroscopic data. Compound 1 exhibited stronger scavenging effect on the stable free radical 1,1-diphenyl-2-picrylhydrazyl than that of alpha-tocopherol.     

南海中华小尖柳珊瑚Muricella sinensis化学成分的研究

从采自中国南海的中华小尖柳珊瑚(Muricella sinensis)中分离得到了1个新的Eunicellane型二萜, 命名为sinensin (1), 和6个已知化合物: 13-去乙酰氧基calicophirin B (2), calicophirin B (3), calicophirin C (4), astrogorgin (5), calicoferol E (6)和calicoferol B (7), 这些化合物的结构是经波谱学实验(1H NMR, 13C NMR, HMQC, HMBC, COSY和NOESY)并与文献报道的数据对照而确定的.     

Limonoids from the leaves of Swietenia macrophylla

One new limonoid of the phragmalin type (1) named Swietenine J with nine known compounds methyl-6-β-hydroxy angolensate (2), 1-O-acetylkhayanolide A(3), Khayanolide E (4), Khayalactone (5), Khayanone (6), 1-O-Acetylkhayanolide B (7), 1-O-Deacetylkhayanolide E (8), Khayanolide A (9), Khayanolide B (10) were isolated from Swietenia macrophylla. The structure of 1 was elucidated on the basis of 1D and 2D- NMR spectroscopic analysis.     

New secoiridoid glycosides from the roots of Picrorhiza scrophulariiflora

Three new secoiridoid glycosides, named picrogentiosides A (1), B (2) and C (3), have been isolated from the underground parts of Picrorhiza Scrophulariiflora, together with the two known compounds plantamajoside (4) and plantainoside D (5). Their structures were established by spectroscopic analyses and comparisons with data from related compounds. A pilot pharmacological study showed that picrogentiosides A (1) and B (2) have an immunomodulatory effect in vitro.     

Phenolic and Triterpenoid Glycosides from Pyrola calliantha

Pyrocallianthasides A ( 1 ) and B ( 2 ), a new dimer and a new mono‐deglucosyl trimer of homoarbutin (=4‐hydroxy‐3‐methylphenyl β‐glucopyranoside), and callianthaside A ( 3 ), a new ursane‐type triterpene glycoside, together with three known phenolic glycosides and three known ursane‐type triterpenoids, were isolated from the whole plants of Pyrola calliantha. The structures of 1 – 3 were elucidated by chemical and spectroscopic methods.     

Novel Method to Prepare Dihydroxy Permethylated beta-Cyclodextrin Isomeric Intermediates for Bifunctional Enzyme Mimics

Natural beta-cyclodextrin was treated with 3.5 equiv of tert-butyldimethylsilyl chloride and then with NaH and MeI in the same reaction vessel to give a mixture of oligosilyl-substituted permethylated beta-cyclodextrins. The mixture was treated with NH(4)F and the resulting 6(A),6(D)-(1), 6(A),6(C)-(2), and 6(A),6(B)-(3) dihydroxy permethylated beta-cyclodextrins were isolated in 7.6-8.9% yields by two silica gel chromatographic separations. The structures of 1-3 were verified by comparison of spectral properties with a known diol (2) or preparing known derivatives (1 and 3). This is a superior way to prepare and isolate dihydroxy permethylated beta-cyclodextrin intermediates for bifunctional enzyme mimics.     

Micranoic acids A and B: two new octanortriterpenoids from Schisandra micrantha

Two novel octanortriterpenoids, micranoic acids A (1) and B (2), along with three known compounds, kadsuric acid (3), 3beta-hydroxy-lanost-9(11),24(25)-dien-26-oic acid (4) and schizandronic acid (5), were isolated from the leaves and stems of Schisandra micrantha. The structures of 1 and 2 were determined by 1D and 2D NMR spectroscopic analysis. Micranoic acids A and B represent a new group of triterpenes in which the entire C-17 side chain has lost. This is the first report of octanortriterpenoids isolated from the family Schisandraceae.     

Five unique compounds: xyloketals from mangrove fungus Xylaria sp. from the South China Sea coast

Five unique metabolites, xyloketals A (1), B (2), C (3), D (4), and E (5), and the known 6 were isolated from mangrove fungus Xylaria sp. (no. 2508), obtained from the South China Sea. The structures of these compounds were elucidated by spectroscopic and X-ray diffraction experiments. Xyloketal A is a ketal compound with a C(3) symmetry and xyloketals B-E are its analogues. It was found that xytoketal C slowly rearranged to xytoketal B in DMSO-d(6)() solution at room temperature. Xyloketal A exhibited the activity of inhibiting acetylcholine esterase.     

New germacrane sesquiterpenes from Salvia chinensis

Two new germacrane sesquiterpenes, called salviadienol A (1) and salviadienol B (2), together with five known compounds, methyl-ent-4-epi-agath-18-oate (3), angelicoidenol (4), clovane-2beta,9alpha-diol (5), dehydrovomifoliol (6) and blumenol A (7), were isolated from Salvia chinensis. Their structures were identified on the basis of spectral characteristics.     

Novel abietane diterpenoids and aromatic compounds from Cladonia rangiferina and their antimicrobial activity against antibiotics resistant bacteria

From Cladonia rangiferina were isolated two novel abietane diterpenoids, hanagokenols A (1) and B (2). Also in this investigation, four known abitetane diterpenoids (3-6), four known labdane diterpenoids (7-10), one known isopimarane diterpenoid (11), and six known aromatic compounds were isolated. These structures were elucidated primarily through extensive NMR experiments. Hanagokenol A (1) was a unique abietane diterpene having an ether linkage between C-6 and C-18 of sugiol. Hanagokenol B (2) is also a unique secoabietane diterpene, having gamma-lactone which occurred by cleavage and subsequently oxidation between C-6/C-7 of 12-hydroxydehydroabietinol. Furthermore, all the isolated compounds (1-17) were tested for the antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE).     

1H and 13C NMR assignments of two new indolic enamide diastereomers from a mangrove endophytic fungus Aspergillus sp

Terpeptin A (1) and B (2), two new members of the indolic enamides, along with three known compounds (3-5) were identified from a strain of Aspergillus sp. (w-6), an endophytic fungus associated with Acanthus ilicifolius. The complete (1)H and (13)C NMR assignments for these compounds were carried out using (1)H, (13)C, DEPT, COSY, HMQC, and HMBC NMR experiments. Terpeptin A and B exhibited modest cytotoxicity against A-549 cell line.