Complete 13C NMR assignments for ent-kaurane diterpenoids from Sideritis species

In this work, the detailed NMR studies and full (13)C NMR assignments for five diterpenoids isolated from Sideritis caesarea and Sideritis athoa are described. The assignments are based on a combination of 1D and 2D NMR techniques including (1)H, (13)C, (1)H-(1)H COSY, gHSQC [(1)J(C,H)] and gHMBCδ(C) [(n)J(C,H)(n=2 and 3)] and NOESY experiments.     

Two New Lycopodine Alkaloids from Huperzia serrata

Two new lycopodine alkaloids, (12β)‐12‐hydroxyhuperzine G ( 1 ) and (5β,6β,15α)‐15‐methyllycopodane‐5,6‐diol ( 2 ), were isolated from the whole plants of Huperzia serrata, together with six known compounds, huperzines A, B, and G, phlegmariurine B, (8β)‐8‐hydroxyphlegmariurine B, and lycoposerramine D. Their structures were elucidated on the basis of spectroscopic analysis, including HR‐ESI‐MS, ¹H‐ and ¹³C‐NMR, DEPT, ¹H,¹H‐COSY, HSQC, HMBC, and NOESY data.     

1H and 13C assignments of two new triterpenes from Cladocolea grahami

The structure elucidation and 1H and 13C assignments of the new triterpenes 3beta-palmitoxy-7beta-hydroxyolean-12-ene (1) and its hydrolysis product 3beta,7beta-dihydroxyolean-12-ene (2) and 3beta-sn-glyceroyl-(1'-palmitoxy)urs-12-ene (3), isolated from the aerial parts of Cladocolea grahami (Loranthaceae), are reported.     

A New Jatrophane Diterpenoid Ester from Euphorbia turczaninowii

A new jatrophane diterpenoid ester （2S, 3S, 4R, 5R, 7S, 8R, 13R, 15R） - 3, 5, 7, 8, 15- pentaacetoxy-9, 14-dioxojatropha-6（17）, 11E-diene was isolated from the whole plant of Euphorbia turczaninowii Kar. ＆ Kit.. Its structure was characterized by spectral analysis and confurmed by X-ray crystallographic analysis.     

Structural determination of a new 2(3 --> 20)abeotaxane with an unusual 13beta-substitution pattern and a new 6/8/6-ring taxane from Taxus cuspidata

A new 2(3 --> 20)abeotaxane with an unusual 13beta-substitution pattern and a new 6/8/6-ring taxane were isolated from the methanol extract of the needles of Taxus cuspidata. The structures were established as 2alpha,7beta-diacetoxy-5alpha,10beta,13beta-trihydroxy-2(3 --> 20)abeotaxa-4(20), 11-dien-9-one (1) and 2alpha,5alpha,7beta,9alpha,13alpha-pentahydroxy-10beta-acetoxytaxa-4(20),11-diene (2) on the basis of 1D and 2D NMR spectral data and high-resolution FAB-MS analyses.     

A New Megastigmane Palmitate and a New Oleanane Triterpenoid from Aster yomena Makino

A new megastigmane palmitate, 9‐oxomegastigm‐5(13)‐ene‐2β‐palmitate ( 1 ), and a new oleanane triterpenoid, (3β)‐3,23,28‐trihydroxyolean‐12‐en‐11‐one ( 2 ), together with three known oleanane‐type triterpenoids, β‐amyrin ( 3 ), erythrodiol ( 4 ), and (3β)‐olean‐12‐ene‐3,23,28‐triol ( 5 ), were isolated from the aerial parts of Aster yomena (Asteraceae). Their structures were identified based on 1D‐ and 2D‐NMR analysis, including ¹H,¹H‐COSY, HSQC, HMBC, and NOESY techniques.     

Terpenoids from the Chinese Liverwort Chiloscyphus polyanthus

A new diterpene, (7α,11β,14β,16R)‐7,11,14‐trihydroxy‐ent‐kaur‐15‐one ( 1 ), and a new sesquiterpene, polyanthuslide ( 2 ), were isolated from the Chinese liverwort Chiloscyphus polyanthus. Their structures were determined on the basis of extensive spectroscopic analyses, and the configuration of 2 was established by X‐ray crystallographic analysis.     

Kaurane-Type Diterpenoids from Liverworts

Seven kaurane-type diterpenoids were isolated from the Taiwanese liverworts Jungermannia truncata. Among them, three are new structures. They are: ent-16-kauren-3, 15-dione (6), ent-16(S)-kauran-3,15-dione (7), and ent-14α-hydroxy-16-kauren-15-one (11). From Plagiochila pulcherrima, three known kaurane alcohols were also isolated along with sesquiterpenoids plagiochilines A, B, C and ent-4β, 10α-dihydroxyaromadendrane.     

Triterpenoids from the Flowers of Salvia miltiorrhiza

A phytochemical investigation of the flowers of Salvia miltiorrhiza Bunge led to the isolation of two new oleanane‐ and ursane‐type triterpenoids, (3α)‐olean‐12‐ene‐3,23‐diol ( 1 ) and (3α)‐urs‐12‐ene‐3,23‐diol ( 2 ), as well as of four known triterpenoids. Their structures were elucidated on the basis of spectroscopic evidence, including 1D‐ and 2D‐NMR, HR‐MS, and the X‐ray analysis, and by comparison with literature data.     

Steroids and an oxylipin from an algicolous isolate of Aspergillus flavus

A new oxylipin, (8E,12Z)-10,11-dihydroxyoctadeca-8,12-dienoic acid (1), a new steroid, 3β,4α-dihydroxy-26-methoxyergosta-7,24(28)-dien-6-one (2), and four known steroids, episterol (3), (22E,24R)-ergosta-7,22-dien-3β,5α,6α-triol (4), (22E,24R)-ergosta-5,22-dien-3β-ol (5), and (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (6), were isolated from the cultures of Aspergillus flavus, an endophytic fungus isolated from the marine red alga Corallina officinalis. Their structures and relative stereochemistry were elucidated by 1D, 2D NMR and mass spectroscopic techniques. 1 and 2 exhibited low activity to inhibit acetylcholinesterase and no activity against plant pathogenic fungi Colletotrichum lagenarium and Fusarium oxysporum.     

Sesquiterpenoids and Diterpenoids from the Liverwort Heteroscyphus Coalitus

Thirteen specimens of Heteroscyphus coalitus were chemically examined. Among the isolated compounds, 1‐hydroxyaromadendr‐4‐en‐3‐one has not been reported previously. A third new chemotype with kauranoids as the major constituents for the liverwort H. coalitus was identified.     

Preparative isolation of guaipyridine sesquiterpene alkaloid from Artemisia rupestris L. flowers using high-speed counter-current chromatography

Although the medicinal plant Artemisia rupestris L. has been widely researched for several decades, its alkaloids have never been isolated before. To our surprise, the alkaloids in the plant were not detected in the stems but detected in the flowers. Herein, a novel and strange guaipyridine sesquiterpene alkaloid with a carboxyl group named rupestine was purified successfully from the total alkaloids extracted from the flowers by high-speed counter-current chromatography (HSCCC). The two-phase solvent system used was composed of ethyl acetate-methanol-water (8:1:7, v/v/v). Fifty six milligrams of rupestine was obtained at over 97% purity and 95% recovery from 200 mg of the total alkaloids in one-step separation. Its structure was elucidated by spectroscopic methods including high resolution ESI-MS, (1)H NMR, (13)C NMR, Heteronuclear Multiple Bond Correlation (HMBC), Heteronuclear Single Quantum Coherence (HSQC), and Nuclear Overhauser Enhancement Spectroscopy (NOESY).     

Structural determination of 3beta-stearyloxy-urs-12-ene from Maytenus salicifolia by 1D and 2D NMR and quantitative 13C NMR spectroscopy

Six pentacyclic triterpenoids, 3beta-stearyloxy-urs-12-ene (1), friedelin (2), 3beta-friedelinol (3), alpha-amyrin (4), beta-amyrin (5), and lupeol (6), have been isolated from the hexane extract of Maytenus salicifolia Reissek (Celastraceae) leaves. The molecular and structural formula as well as the stereochemistry of a new pentacyclic triterpene (1) were determined using data obtained from 1H and 13C NMR spectra, DEPT135 and by 2D HSQC, HMBC, COSY and NOESY experiments. The molecular formula C48H84O2 was established using quantitative 13C NMR, and the molecular weight (692 Da) was confirmed by elemental analysis and mass spectrometry (GC-MS).     

Complete 1H and 13C data assignments of two new guaianolides isolated from Ainsliaea fragrans

Two new guaianolides, 8alpha-hydroxy-11alpha,13-dihydroglucozaluzanin C and 11alpha,13-dihydroglucozaluzanin C, were isolated from Ainsliaea fragrans, along with two known guaianolides, 8alpha-hydroxy-11alpha,13-dihydrozaluzanin C and glucozaluzanin C. The structures of the new compounds were unambiguously established by HR-ESI-MS, one-dimensional (1D) (DEPT), two-dimensional (2D) ((1)H-(1)H COSY, HSQC, HMBC, ROESY) NMR experiments and by comparison with structurally related compounds. The known compounds were identified by comparison of spectral data with published references. Some NMR data of the known compounds were reported for the first time.     

Monoterpenoid Indole Alkaloids from Alstonia mairei

Three new monoterpenoid indole alkaloids, (14α,15α)‐14,15‐epoxyaspidofractinine ( 1 ) and maireines A and B ( 2 and 3 , resp.), together with 19 known alkaloids, were isolated from the leaves and twigs of Alstonia mairei. The structures of the new compounds were elucidated by 1D‐ and 2D‐NMR spectroscopic methods in combination with MS experiments.     

Reductive Cleavage of the Te—Te Bond in Diphenyl Ditelluride by the Sm—CrCl3（cat.）System： Preparation of Telluroesters and Unsymmetrical Phenyltellurides

The reduction of diphenyl ditelluride by the Sm/CrCl3(cat.) system led to a telluride anion.This species reacted with acid chlorides,alkyl halides,and α，β-unsaturated enoates or α，β-unsaturated ene nitriles to afford telluroesters and unsymmetrical phenyltellurides,respectively,in moderate to good yields under mild and neutral conditions.     

Asymmetric Synthesis of (R)-Fluoxetine: A Practical Approach Using Recyclable and in-situ Generated Oxazaborolidine Catalyst

A practical route for the synthesis of (R)-fluoxetine•HCl (ee＝96%) in 56% overall yield was described. The key intermediate (R)-3-chloro-1-phenyl-1-propanol was obtained by the asymmetric reduction of prochiral 3-chloropropiophenone using in-situ generated oxazaborolidine catalyst derived from (S)-α,α-diphenylprolinol. The chiral procatalyst (S)-α,α-diphenylprolinol was recovered quantitatively and recycled. An improved practical synthesis of (S)-α,α-diphenylprolinol was also discussed.     

Steroidal Alkaloids from the Roots and Rhizomes of Vertrum nigrum L.

Two new steroidal alkaloids, neoverapatuline ( 1 ) and (1β,3α,5β)‐1,3‐dihydroxyjervanin‐12‐en‐11‐one ( 2 ), together with the four known compounds, veratramine ( 3 ), rubijervine ( 4 ), veratrosine ( 5 ), and veratroylzygadenine ( 6 ), were isolated from the roots and rhizomes of Veratrum nigrum L. Their structures were established through combined analyses of physicochemical properties and spectroscopic evidence. All compounds 1 – 6 were tested for their cytotoxicities in vitro against the human glioma cell line SF188.     

密脉鹅掌柴中三萜类新化合物12α,13-二羟基齐墩果烷-3酮-28酸和新细胞周期抑制剂齐墩果酮酸

12α, 13-Dihydroxyolean-3-oxo-28-oic acid (1), a new pentacyclic triterpene, was isolated from Scheffiera venulosa (Wight et Am.) Harms through a bioassay-guided fractionafion procedure, together with the known oleanonic acid (2) as a new cell cycle inhibitor. Structures were estabfished by spectroscopy. Compound 2 inhibited the proliferation of K562 cells with the IC50 value of 0.13 lamol/mL by the SRB method and inhibited the cell cycle of tsFT210 cells at the G0/G1 phase at the concentration higher than 10 μg/mL.     

Two isomeric epoxysitosterols from Rhododendron formosanum: 1H and 13C NMR chemical shift assignments

1H and 13C NMR assignments of the two isomeric epoxysitosterols, 5,6 alpha-epoxy-5 alpha-stigmastan-3 beta-ol (1) and 5,6 beta-epoxy-5 beta-stigmastan-3 beta-ol (2), isolated from the leaves of Rhododendron formosanum Hemsl were achieved by 1D and 2D techniques such as DEPT, HMBC, HMQC, COSY and NOESY.