A new triterpenoid saponin from the roots of Platycodon grandiflorum

A new triterpenoid saponin, 3-O-β-D-glucopyranosyl 16-oxo-platycodigenin 28-O-β-D-apiofuranosyl-(1→3)-β-D-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyra-nosyl ester, was isolated from the roots of Platycodon grandiflorum, together with three known saponins, including platycodin D, deapio platycoside E and platycoside E. The structure of the new compound, named 16-oxo-platycodin D, was elucidated on the basis of spectroscopic data.     

Furostanol saponins with inhibitory action against COX-2 production from Tupistra chinensis rhizomes

Two furostanol saponins were obtained from the n-butanol fraction of methanol extract from Tupistra chinensis rhizomes,a folk medicine of Shennongjia Forest District of Hubei Province.Their structures were determined as (25S)-26-O-(β-D-glucopyranosyl)- furost-1β,3β,22α,26-tetrol-3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glucopyranoside (1) and (25R)- 26-O-(β-D-glucopyranosyl)-furost-1β,3β22α,26-tetrol 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyranosyl-(1→2)-β-D-glu- copyranoside (2),on basis of chemical and spectroscopic evidences.1 and 2 displayed marked inhibitory action towards COX-2 production in macrophages of the rat abdomen induced by LPS at 20μg/mL.     

Two new C-glycosylflavones from Mimosa pudica

Two new C-glycosylflavones were isolated from the whole plant of Mimosa pudica,and their structures were determined as 6,7,3′,4′-tetrahydroxyl-8-C-[α-L-rhamnopyranosyl-(1→2)]-β-D-glucopyranosyl flavone(1),5,7,3′,4′-tetrahydroxy-8-C[β-D- apiose-(1→4)]-β-D-glycopyranosyl flavone (2).Their structures elucidated by chemical and spectroscopic analysis including IR,MS,1D and 2D NMR spectra.     

A new triterpene glycoside from sea cucumber Holothuria leucospilota

A new triterpene glycoside, leucospilotaside A, along with a known saponin, isolated from sea cucumber Holothuria leucospilota, and its structure was elucidated as 3β-O-[4-O-sodiumsulfate-β-D-quinovopyranosyl-(1→2)-β-D-xylopyranosyl]-holosta-22-ketone-9-en-17α,25α-diol (1) by extensive spectroscopic analysis and chemical methods. Leucospilotaside A (1) has a ketone carbonyl group (22) in the aglycon side chain.     

A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).     

Two new saponins from Anemarrhena asphodeloides Bge.

Two new saponins 3-O-β-D-glucopyranosyl (1→2)-β-D-mannopyranosyl sarsasapogenin, named timosaponin A IV(1) and (5β, 25S)-26-O-β-D-glucopyranosyl-furost-20(22)-en-3,26-diol-3-O-β-D-glucopyranosyl (1→4) glucopyranosyl (1→2)-β-D-galacopyranoside, named timosaponin B IV(2), were isolated by silica gel column chromatography and preparative HPLC from Anemarrhena asphodeloides Bge. Their structures were elucidated by chemical characters and spectroscopic analysis.     

Synthesis of an antimetastatic tetrasaccharide β-D-Gal-(1→4)-β-d-GlcpNAc-(1→6)-α-D-Manp-(1→6)-β-D-Manp-OMe

An antimetastatic tetrasaccharide T₁,β-D-Gal-（1→4）-β-D-GlcpNAc-（1→6）-α-D-Manp-（1→6）-β-D-Manp-OMe,was synthesized with two approaches.The first approach was a conventional method employing thioglycoside and Koenigs-Knorr glycosylation reaction in 24%overall yield.The second one was a novel route through the azidoiodo-glycosylation strategy by using 2-iodo-2-deoxylactosyl azide as the donor in 36%overall yield.     

Synthesis ofa trimeric lignin model compound composed ofol-O-4 and β-O-4 linkages under microwave irradiation

A trimeric lignin model compound composed of α-O-4 and β-O-4 linkages was prepared by the microwave-assisted synthesis, which consisted of three steps： （a） the synthesis of 3-methoxy-4- benzyloxyacetophenone （2） from acetovanillone （1）, （b） the bromination of compound 2 to produce 3- methoxy-4-benzyloxy-α-bromoacetophenone （3）, and （c） followed by a nucleophilic substitution of compound （3） to obtain 3-methoxy-4-benzyloxy-α-（3-methoxy-4-（1-propenyl）phenol）-acetophenone （4）. The target product was characterized by MS, 1H NMR and 13C NMR spectroscopy. It was found that the trimeric compound synthesized can be used as a preferable lignin model compound because it contains guaiacyl structural unit （3-methoxy-4-hydroxy phenyl propane） linked by α-O-4 and β-O-4 linkages. In addition, under the conditions of microwave irradiation, the reaction time of each step is significantly reduced, and the selectivity of target product is greatly improved. The yields of each step and the overall sequence are 95.31%. 87.3%. 90.6% and 75.4% （95.31%× 87.3% × 90.6%）. respectively.     

Two new glycosides from the genus of Cassia

Two new glycosides were isolated and characterized by spectral analysis from the seeds of Cassia obtusifolia and the leaves of Cassia angustifolia.The structure was elucidated as 1-hydroxyl-2-acetyl-3,8-dimethoxynaphthalene-6-O-β-D-apiofuranosyl- (1→2)-β-D-glucopyranoside and 2-acetyl-3-methyl-8-methoxyl-1,4-naphthoquinone-6-O-β-D-glucopyranoside.     

A new coumarin glycoside from Daphne giraldii

A new coumarin glycoside was isolated from the ethanol extract of the barks of stem of Daphne giraldii Nitsche. Its structure was defined as daphnetin 8-O-b-D-glucopyranosyl-(1→6)-b-D-glucopyranoside on the basis of spectral evidences.     

Design, synthesis and antiproliferative activities of novel 5H-pyridazino[4,5-b]indoles

A novel series of 5H-pyridazino[4,5-b]indoles were designed and synthesized in order to find novel potent anticancer compounds.The structures were confirmed by ~1H NMR and MS.Their antiproliferative activities against two cancer cell lines were tested by the MTT method in vitro.Three of compounds (1e,1g,and 1h) exhibited potent antiproliferative activities,especially compound 1h (with IC_(50) values of 5.2μmol/L and 1.9μmol/L against Bel-7402 and HT-1080,respectively).The preliminary structure-activity relationships of 5H-pyridazino[4,5-b]indole derivatives were discussed.     

Tetracyclic triterpenoids isolated from semi-mangrove plant Hibiscus tiliaceus

A continuing phytochemical study on the semi-mangrove plant Hibiscus tiliaceus yielded two new tetracyclic triterpenoids （3β,24S）-19（10→9）-abeo-8α,9β,10α-eupha-5,25（26）-dien-3,24-diol （tiliacol A, 1 ）, and （3β,23Z）-19（10→9）-abeo-8α,9β,10α-tircalla-5,23-dien-3,25-diol （tiliacol B, 3）, together with one known analog （2）. Their structures were elucidated on the basis of extensive spectral analyses （MS, IR, 1D NMR and 2D NMR） and comparison with literature compounds. Compound 2 showed potent cytotoxicity against both P388 and HeLa cells with ICon values of 11.2 μmol/L and 11.5 μmol/L, resoectively.     

Conformational and stereoelectronic investigation of chloromethyl methyl sulfide and its sulfinyl and sulfonyl analogs

Three compounds based on polyoxometalate building blocks, [Cu(en)₂]{[Cu(en)₂]₂[Mo^VI₅Mo^V₃V^IV₈O₄₀(PO₄)]} · 4H₂O (1), [Co(en)₂]{[Co(en)₂]₂[HMo^VI₄Mo^V₄V^IV₈O₄₀(PO₄)]} · 5H₂O (2) and [Ni(en)₂]{[Ni(en)₂]₂[Mo^VI₅Mo^V₃V^IV₈O₄₀(VO₄)]} · 2H₂O (3) (en = ethylenediamine), have been synthesized and characterized by elemental analysis, IR, XPS, XRD, TGA and single-crystal X-ray diffraction analysis. The result of structure determination shows that isomorphic compounds 1, 2 and 3 feature a one-dimensional chain built from the reduced tetra-capped pseudo-Keggin polyoxoanion, which is further interconnected by [M(en)₂]²⁺ (M = Cu, Co and Ni) groups via the terminal oxygen atoms of polyoxoanions. The crystal data for these compounds are the following: 1, monoclinic, space group C2/c, a = 26.702(3) Å, b = 13.4539(14) Å, c = 19.5987(19) Å, β = 108.650(2)°, V = 6671.0(12) Å³, Z = 4; 2, monoclinic, space group C2/c, a = 26.244(3) Å, b = 13.5070(17) Å, c = 19.581(3) Å, β = 106.881(2)°, V = 6641.8(15) Å³, Z = 4; 3, monoclinic, space group C2/c, a = 26.2789(15) Å, b = 13.5408(6) Å, c = 19.6312(9) Å, β = 106.2590(10)°, V = 6706.1(6) Å³, Z = 4. Variable-temperature magnetic susceptibility measurements of compounds 1 and 3 reveal the feature of antiferromagnetic exchange in these compounds.     

Iridium aminyl radical complexes as catalysts for the catalytic dehydrogenation of primary hydroxyl functions in natural products

The cationic tetra-coordinated 16 electron complex [Ir(trop₂dach)]⁺OTf⁻ (1) where (OTf⁻ = CF₃SO₃⁻) and the neutral amine amido complex [Ir(trop₂dach-1H)] (2) were isolated and structurally characterized. The NH function in 1 is easily deprotonated (pK_a^DMSO = 10.5) to yield the amino amido complex [Ir(trop₂dach-1H)] (2), which is deprotonated at pK_a^DMSO = 19.6 to the anionic di(amido) iridate [Ir(trop₂dach-2H)]⁻ (3); [(R,R)-top₂dach stands for the tetrachelating diamino diolefin ligand (R,R)-N,N′-bis(5H-dibenzo[a,d]cyclohepten-5-yl)-1,2-diaminocyclohexane; (R,R)-top₂dach-1H and (R,R)-top₂dach-2H indicate the mono and double deprotonated form]. Complex 3 is easily oxidized by 1,4-benzoquinone (BQ) to the neutral iridium aminyl radical complex [Ir(trop₂dach-2H)] (4). In combination with BQ as hydrogen acceptor and catalytic amounts of base, 4 serves as catalyst in the highly efficient dehydrogenation of functionalized primary alcohols to the corresponding aldehydes, RCH₂OH + BQ → RCHO + H₂BQ (H₂BQ = catechol). Alcohols like geraniol and retinol are rapidly converted to geranial and retinal, while the conversion of sterically hindered alcohols like lavandulol is slower and the primary product, lavandulal, isomerizes to isolavandulal in a classical base-catalyzed reaction.     

Synthesis and characterization of a tetranuclear copper(Ⅱ) complex with a chiral Schiff base ligand

The title complex l-[Cu^Ⅱ₄（Hvap）₂（vap）₂（MeOH）₂]（CIO₄）₂ 1 has been synthesized and characterized by EA. IR,TGA,solid-state CD spectra and X-ray single-crystal analyses（l-H₂vap’.a Schiff base ligand derived from the condensation of o-vanillin and l-2-amino-3-phenyl-l-propanol）.Complex 1 crystallizes in monoclinic system,chiral space group P2₁ with a =10.4257（18）.b = 21.695（4）,c = 15.721（3）A,β= 94.443（3）.V= 3545.1（11） ³,Z=2,Cu₄C₇₀H₇₈N₄O₂₂Cl₂.Mr= 1652.42,D_c= 1.548 g/cm³, F（000）= 1704 andμ（MoKα） = 1.338 mm^-1.The final R = 0.0682 and wR = 0.1420 for 6170 observed reflections with I > 2σ（I） and R = 0.1775 and wR = 0.1830 for all data.The structure of complex 1 contains a boat-shaped(Cu₄O₄} motif.The solid-state CD spectra confirm the chiral nature of complex 1.     

A new triterpene and a saponin from Centella asiatica

A new triterpene and a saponin,named 2α,3β,23-trihydroxyurs-20-en-28-oic acid(1)and 2α,3β,23-trihydroxyurs-20-en-28-oic acid O-α-L-rhamnopyranosyl-(1→4)-O-β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl ester(2),have been isolated from the aerial part of Centella asiatica.Their structures were elucidated by spectral methods,including 2D-NMR spectra.     

Do lipases also catalyse the ring cleavage of inactivated cyclic trans-β-lactams?

Twelve-membered cyclic cis- and trans-β-lactams 1b and 2b and the corresponding cyclic cis- and trans-β-amino acid enantiomers, 1a, 1c and 2a, 2c were prepared through the CAL-B-catalysed enantioselective ring cleavage of racemic cis-13-azabicyclo[10.2.0]tetradecan-14-one, (±)-1, and trans-13-azabicyclo[10.2.0]tetradecan-14-one, (±)-2. High enantioselectivities (E >200) were observed for the ring opening of both the cis- and trans-β-lactams when the Lipolase-catalysed reactions were performed with 0.5 equiv of H₂O in i-Pr₂O at 70 °C. The resolved β-lactams 1b and 2b (yield ⩾47%) and β-amino acids 1a and 2a (yield ⩾32%) could be easily separated.     

Synthesis and characterization of novel intramolecularly O,C,O-coordinated heteroleptic organostannylenes and their tungstenpentacarbonyl complexes

The syntheses are reported of the novel heteroleptic organostannylenes [2,6-(ROCH₂)₂C₆H₃]SnCl (1, R = Me; 2, R = t-Bu) and of their tungstenpentacarbonyl complexes [2,6-(ROCH₂)₂C₆H₃](X)SnW(CO)₅ (3, X = Cl, R = Me; 4, X = Cl, R = t-Bu; 5, X = H, R = Me). The compounds were characterized by means of elemental analyses, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopies, electrospray mass spectrometry and in case of 3 and 4 also by single crystal X-ray diffraction analysis. For the two latter compounds the substituents bound at the ether oxygen atom control the strength of intramolecular O → Sn coordination. Thus, the O–Sn distances amount to 2.391(5)/2.389(5) (3) and 2.464(3)/2.513(3) Å (4).     

First synthesis of 5,6-branched galacto-hexasaccharide,the dimer of the trisaccharide repeating unit of the cell-wall galactans of Bifidobacterium catenulatum YIT 4016

α-d-Galactopyranosyl-(1→6)-[β-d-galactofuranosyl-(1→5)]-β-d-galactofuranosyl-(1→6)-β-d-galactofuranosyl-(1→5)-[α-d-galactopyranosyl-(1→6)]-β-d-galactofuranose, the dimer of the trisaccharide repeating unit of the cell-wall galactans of Bifidobacterium catenulatum YIT 4016, has been synthesized as its dodecyl glycoside 2 by coupling of 2,3,4,6-tetra-O-benzyl-α-d-galactopyranosyl-(1→6)-[6-O-acetyl-2,3,5-tri-O-benzoyl-β-d-galactofuranosyl-(1→5)]-2-O-acetyl-3-O-benzyl-β-d-galactofuranosyl trichloroacetimidate 14 with dodecyl 2,3,4,6-tetra-O-benzyl-α-d-galactopyranosyl-(1→6)-[2,3,5-tri-O-benzoyl-β-d-galactofuranosyl-(1→5)]-2-O-acetyl-3-O-benzyl-β-d-galactofuranoside 16. The trisaccharide trichloroacetimidate donor 14 and trisaccharide acceptor 16 were regiospecifically prepared by employing 3-O-benzyl-1,2-O-isopropylidene-α-d-galactofuranose 4 as the glycosyl acceptor, and isopropyl 2,3,4,6-tetra-O-benzyl-1-thio-β-d-galactopyranoside 5 and 6-O-acetyl-2,3,5-tri-O-benzoyl-β-d-galactofuranosyl trichloroacetimidate 9 as glycosyl donors.     

Solvothermal synthesis and characterization of new aluminophosphate layers templated by imidazolium ions

Two imidazolium templated aluminophosphate layers [N₂C₃H₅]₂ [Al₃P₄O₁₆H] (1) and [N₂C₃H₅] [AlP₂O₈H₂(OH₂)₂] (2) have been synthesized under solvothermal conditions at 160°C. The effects of P/Al ratio the amount of organic amine and the type of solvent on the products are investigated. Their structures are characterized by single-crystal X-ray diffraction (XRD) powder XRD ²⁷Al DOR NMR ³¹P MAS NMR and thermal analyses. Both compounds exhibit unusual structure architectures which are different from previously reported [Al₃P₄O₁₆]^3- and [AlP₂O₈]^3- families. Compound 1 crystallizes in the triclinic space group of P1̄ (No. 2) with a=8.940(2), b=9.360(2), c=11.721(2) Å, α=97.10(2), β=95.10(2), γ=91.91(2)°, V=968.4(3) Å³ and Z=2. The structure contains a new macroanionic inorganic sheet characterized by a series of double six-membered ring (D6R) in which Al moieties (including AlO₄ and AlO₅) and P moieties [including PO₄, PO₃(=O) and PO₂(=O) (OH)] are corner-shared through oxgens in an alternative manner. Compound 2 crystallizes in the monoclinic space group of C2/c (No. 15) with a=21.854(4), b=7.188(2), c=6.990(2) Å, β=103.77(2)°, V=1063.5(5) Å³ and Z=4. The structure is based on a new two-dimensionally connected inorganic network containing eight-membered rings in which AlO₄(OH₂)₂ and PO₂(OH)(=O) units are connected alternatively.