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.     

Xanthone O‐Glycosides from the Roots of Pteris Multifida

Two new xanthone glycosides and six known compounds were isolated from the roots of Pteris multifida. Based on spectroscopic and chemical methods, the structures of the new compounds were elucidated as 1‐hydroxy‐4,7‐dimethoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1→2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 1 ), and 1,3‐dihydroxy‐7‐methoxy‐8‐(3‐methyl‐2‐butenyl)‐6‐O‐α‐L‐rhamnopyranosyl‐(1 →2)‐[β‐D‐glucopyranosyl‐(1→3)]‐β‐D‐glucopyranosylxanthone ( 2 ), respectively.     

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.     

Triterpene Acids from the Leaves of Planchonella Duclitan (Blanco) Bakhuizan

From the methanolic extract of the leaves of Planchonella duclitan, 2α,3α,19α,23‐tetrahydroxy‐13,27‐cyclours‐11‐en‐28‐oic acid (1), myrianthic acid (2), 2‐hydroxyursolic acid (3), ursolic acid (4), pomolic acid (5), rotundic acid (6), and jacoumaric acid (7) were isolated, and their structures were elucidated on the basis of their spectroscopic analysis. Among them, compound 1 was a new cyclopropyl ursane‐type triterpene acid. Additionally, compounds 4 and 7 showed significant cytotoxicity toward human colorectal carcinoma cell line HT29 and human breast carcinoma cell line MCF‐7 with IC₅₀ values ranging from 5.8 ± 1.4 to 6.5 ± 1.9 μM.     

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.     

Complete 1H NMR assignments of pyrrolizidine alkaloids and a new eudesmanoid from Senecio polypodioides

Chemical investigation of the aerial parts of Senecio polypodioides lead to the isolation of the new eudesmanoid 1β‐angeloyloxyeudesm‐7‐ene‐4β,9α‐diol ( 1 ) and the known dirhamnosyl flavonoid lespidin ( 3 ), while from roots, the known 7β‐angeloyloxy‐1‐methylene‐8α‐pyrrolizidine ( 5 ) and sarracine N‐oxide ( 6 ), as well as the new neosarracine N‐oxide ( 8 ), were obtained. The structure of 1 and 8 was elucidated by spectral means. Complete assignments of the ¹H NMR data for 5 , 6 , sarracine ( 7 ), and 8 were made using one‐dimensional and two‐dimensional NMR experiments and by application of the iterative full spin analysis of the PERCH NMR software. Copyright © 2014 John Wiley & Sons, Ltd.     

Highly Oxygenated Triterpenoids from the Marine Red Alga Laurencia mariannensis (Rhodomelaceae)

Two new and one known squalenoid‐derived triterpenoids, namely, laurenmariannol ( 1 ) and (21α)‐21‐hydroxythyrsiferol ( 2 ), and the known thyrsiferol ( 3 ) were isolated and identified from the marine red alga Laurencia mariannensis, which was collected off the coast of Hainan and Weizhou Islands of China. The structures of these compounds were established by means of spectroscopic analyses, as well as by comparison with literature data. Compounds 1 and 2 displayed significant cytotoxic activity against P‐388 tumor cells with IC₅₀ values of 0.6 and 6.6 μg/ml, respectively.     

CuI/amino acid‐catalyzed coupling and cyclization of β‐bromo‐α,β‐unsaturated amides with terminal alkynes leading to (3Z)‐3‐alkylidenepyrrol‐1‐ones

β‐Bromo‐α,β‐unsaturated amides are coupled and cyclized with terminal alkynes in DMF at 110 °C in the presence of a catalytic amount of CuI and amino acid along with a base to give the corresponding (3Z)‐3‐alkylidenepyrrol‐1‐ones in moderate to good yields. Copyright © 2013 John Wiley & Sons, Ltd.     

Chemical Constituents from Alafia Barteri Oliv. Leaves with Cytotoxic Activity

Methanol extract of Alafia barteri leaves showed cytotoxic activity on leukaemia carcinoma K562, and hepatic liver cancer cells WRL (IC₅₀ values 193.1 and 225.0 μM respectively). Isolation of the extract gave ursane triterpenoid, 28‐acety‐urs‐5,20‐dien‐2β,3β,24α‐triol, 1 , together with undecanol, 2 , stigmasterol, 3 and octadecanoic acid, 4 . The structures of these compounds were identified by spectroscopic analysis, including MS, 1D and 2D NMR, and supported with literature data. Compound 1 exhibited cytotoxic activity against K‐562 at 50 and 100 μM concentrations with IC₅₀ 74.22 μM, while compounds 2 , 3 and 4 showed low inhibition of WRL, MCF‐7 and COLO cell lines.     

Iodobenzene‐Catalyzed Synthesis of α‐Azidoketones and α‐Thiocyanatoketones from Aryl Ketones with MCPBA as a Cooxidant

Iodobenzene‐catalyzed synthesis of α‐azidoketones and α‐thiocyanatoketones from aryl ketones with MCPBA as a cooxidant is described. The method is simple, rapid and practical, generating α‐azidoketones and α‐thiocyanatoketones from the aryl ketone without isolation of α‐tosyloxyketones in good to excellent yields.     

Photochemische Reaktionen von Cyclopentadienylbis(ethen)rhodium mit Benzolderivaten

Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Benzene Derivatives During UV irradiation of [CpRh(C₂H₄)₂] ( 1 ) (Cp = η⁵‐C₅H₅) in hexane in the presence of hexamethylbenzene the di‐ and trinuclear arene bridged complexes [(CpRh)₂(μ‐η³ : η³‐C₆Me₆)] ( 3 ) and [(CpRh)₃(μ₃‐η² : η² : η²‐C₆Me₆)] ( 4 ) are formed besides known [CpRh(η⁴‐C₆Me₆)] ( 2 ). It was shown by a separate experiment that 3 besides small amounts of 4 is formed by attack of photochemically from 1 arising CpRh fragments at the free double bond of the η⁴‐bonded benzene ring in 2 . Irradiation of 1 in the presence of diphenyl (C₁₂H₁₀) affords the compounds [(CpRh)₂(μ‐η³ : η³‐C₁₂H₁₀)] ( 5 ) and [(CpRh)₃(μ₃‐η² : η² : η²‐C₁₂H₁₀)] ( 6 ) as analogues of 3 and 4 , in the presence of triptycene (C₂₀H₁₄) only [(CpRh)₂(μ‐η³ : η³‐C₂₀H₁₄)] ( 7 ) is obtained; the bridging in 5 , 6 , and 7 always occurs via the same six‐membered ring of the corresponding ligand system. During the photochemical reaction of 1 in the presence of styrene (C₈H₈) substitution of the ethene ligands by the vinyl groups with formation of [CpRh(C₂H₄)(η²‐C₈H₈)] ( 8 ) and known [CpRh(η²‐C₈H₈)₂] ( 9 ) is observed exclusively. The new complexes were characterized analytically and spectroscopically, in the case of 3 also by X‐ray structure analysis.     

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.     

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.     

A New Abietane Diterpenoid from Plectranthus bishopianus Benth.

Chemical examination of the MeOH extract of Plectranthus bishopianus Benth ., a rare and endangered plant, resulted in isolation of a new abietane diterpene, 6β‐hydroxy‐7α‐methoxyroyleanone ( 1 ), along with two more diterpenoids, 6,7‐dehydroroyleanone, and 6β,7α‐dihydroxyroyleanone, a triterpene oleanolic acid, and two sterols, β‐sistosterol and stigmasterol. The structures of the isolated compounds were elucidated on the basis of spectroscopic data and also by comparison with authentic samples.     

Development and validation of a single HPLC method for determination of α‐tocopherol in cell culture and in human or mouse biological samples

A straightforward and common analytical method for α‐tocopherol (αT) determination in various biological samples, including plasma, red blood cells (RBC), tissues and cultured cell lines, was developed and validated, using a reverse phase‐chromatographic method (RP‐HPLC). Even though many chromatographic methods for αT determination have been reported, most of them require readjustment when applied to different types of samples. Thus, an effective and simple method for αT determination in different biological matrices is still necessary, specifically for translational research. This method was applied using a C₁₈ column (250 × 4.6 mm, 5 µm particle size) under isocratic elution with MeOH:ACN:H₂O (90:9:1 v/v/v) at a flow rate of 1 mL/min and detected using photodiode array at 293 nm. Linearity (r >0.9997) was observed for standard calibration with inter‐ and intraday variation of standard <4%. Lower limits of detection and quantification for αT in this assay were 0.091 and 0.305 µg/mL respectively. Validation proved the method to be selective, linear, accurate and precise. The method was successfully applied in great variety of biological samples, that is, human and mouse plasma, RBCs, murine tissues and human/mouse/rat cultured cell lines. More importantly, a single protocol of extraction and detection can be applied, making this method very convenient for standardization of different types of samples. Copyright © 2014 John Wiley & Sons, Ltd.     

Sesquiterpenoids and Their Glycosides from Gynura procumbens

Chemical investigation of the MeOH extract of the leaves of Gynura procumbens (Lour .) Merr . afforded one new sesquiterpenoid, muurol‐4‐ene‐1β,3β,10β‐triol ( 1 ), and two sesquiterpene glycosides, muurol‐4‐ene‐1β,3β,10β‐triol 3‐O‐β‐D ‐glucopyranoside ( 2 ) and muurol‐4‐ene‐1β,3β,15‐triol 3‐O‐β‐D ‐glucopyranoside ( 3 ), together with three known sesquiterpenoids. Their structures were elucidated on the basis of spectroscopic analyses and chemical methods.     

A Convenient and Versatile Method for the Preparation of α‐Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates

The ozonolysis of 1‐substituted allyl silyl ethers or 1‐substituted allyl carboxylates followed by treatment with bases gave the corresponding α‐silyloxymethyl‐ or α‐acyloxymethyl‐ketones in good yields. It is proposed to proceed via the corresponding α‐silyloxy‐ or α‐acyloxyaldehydes intermediates followed by 1,4‐group migration. The results of theoretical calculations are applicable to explain the experimental results.     

Synthesis and Nucleophilic Addition Reactions of Tricarbonyl[η5‐2‐(phenylthio)hexadienyl]iron Hexafluorophosphate

3‐Phenylthio‐3‐sulfolene ( 1 ) was readily converted to a C‐5 substituted product 2 , which upon thermolysis and complexation with Fe₂(CO)₉ gave (η⁴‐diene)iron complexes 3a and 3b . Treatment of 3a and 3b with aq. HPF₆ and Ac₂O provided the title compound 5 , which reacted regio‐ and stereospecifically with some nucleophiles to give the addition products 3b and 7 .     

Mn(III)‐Mediated Chlorination of Conjugated Ketones

Mn(III)‐Cl formed by the reaction of Mn(OAc)₃ and hydrochloric acid in situ, reacted with α,β‐unsaturated ketones readily to afford α,β‐dichloroketones in good yields under mild conditions. The products are key precursors for synthesis of conjugated alkynones and other organic compounds.