A new spirostanol saponin from the rhizomes of Paris mairei

A new spirostanol steroidal saponin,named maireioside A(1),together with three known steroidal saponins,hypoglaucin G(2), parisaponin I(3),and diosgenin-3-O-α-L-rhamnopyranosyl(1→4)-[α-L-rhamnopyranosyl(1→2)]-β-D-glucopyranoside(4),were isolated from the rhizomes of Paris mairei.The structure elucidation was accomplished by 1D and 2D NMR methods,HR-ESI-MS, and hydrolysis.     

Two triterpene glycosides from the sea cucumber Bohadschia marmorata Jaeger

Further studies on the sea cucumber Bohadschia marmorata Jaeger led to the isolation of a new holostan-type triterpene glycoside,Marmoroside C（1）together with a known triterpene glycoside（2）.On the basis of spectroscopic analyses,including two- dimensional NMR techniques,and chemical reactions,the structure of the new triterpene glycoside was elucidated as 3-O-[3-O- methyl-β-D-glucopyranosyl-（1→3）-β-D-glucopyranosyl-（1→4）-β-D-quinovopyranosyl-（1→2）-4-O-sodium-sulfato-β-D-xylo- pyranosyl]-25-acetoxy-22-oxo-9（11）-holostene-3β,12α,17α-triol.     

Synthesis ofα-D-GlcpNAc-（1→2）-[α-D-ManpNAc-（1→3）-]α-L-Rhap-（1→2）-α-L-Rhap-（1→3）-α-L-Rhap,the repeating unit of O10 antigen from Acinetobacter baumannii

An efficient synthesis ofα-D-GlcpNAc-（1→2）-[α-D-ManpNAc-（1→3）-]α-L-Rhap-（1→2）-α-L-Rhap-（1→3）-α-L-Rhap（1）, the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks,p- methoxylphenyl 2,4-di-O-benzoyl-α-L-rhamnopyranoside（2）;2-O-allyloxycarbonyl-3,4-di-O-bcnzoyl-α-L-rhamnopyranosyl tri- chloroacetimidate（3）;4-methoxylphenyl 3-O-allyloxycarbonyl-4-O-benzoyl-α-L-rhanmopyranoside（4）;2-azido-3-O-benzoyl-2- deoxy-4,6-O-isopropylidene-α-D-mannopyranosyl trichloroacetirnidatc（5）;2-azido-3,4,6-tri-O-benzoyl-2-deoxy-α,β-D-glucopyr- ano syl trichloroacetimidatc（6）.The total yield of 1 from 4 was 4.7%.     

Synthesis of di-and tetrasaccharide containing 6-deoxytalose from the O-antigenic polysaccharide of B. pseudomallei strain 304b

Synthesis of the disaccharide β-D-Glup-(1→3)-6-deoxy-α-L-Talp Ⅱ,and its dimer Ⅲ from the O-antigenic polysaccharide of Burkholderia pseudomallei strain 304b,were achieved through assembly of suitably synthesized building blocks,4-methoxylphenyl 6-deoxy-2,4-di-O-benzoyl-α-L-talopyranoside (7),3-O-allyl-2,4,6-tri-O-benzoyl-α,β-D-glucopyranosyl trichloroacetimidate (8) and 2,3,4,6-tetra-O-benzoyi-α,β-D-glucopyranosyl trichloroacetimidate (Ⅱ).The total yield of Ⅲ from 4-methoxyiphenyl 2,3-O-isopropylidene-α-L-rhamnopyranoside (1) was 18%.     

Two new acetylated ginsenosides from the roots of Panax quinquefolium

Two new acetylated ginsenosides, 20（S）-protopanaxatriol-6-O-α-L-rhamnopyranosyl （1 → 2）-β-D-6＇-O-acetylglucopyranoside （1） and 20（R）-protopanaxatrol-6-O-α-L-rhamnopyranosyl （1 → 2）-β-o-6＇-O-acetylglucopyranoside （2）, were isolated from the roots of Panax quinquefolium. The structures were elucidated on the basis of spectroscopic techniques and chemical means.     

Flavonoid triglycosides from the seeds of Camellia oleifera Abel

Two flavonoid triglycosides, kaempferol 3-O-{ β-D-glucopyranosyl-（1→2）-[α-L-rhamnopyranosyl-（1→ 6）]-β-D-glucopyranoside} （1） and kaempferol 3-O-{ β-D-xylopyranosyl-（1 → 2）-[α-L-rhamnopyranosyl-（1→6）]-β-D-glucopyranoside } （2）, were isolated from the seed of Camellia oleifera Abel. The absolute configuration of compound 1 was established on the basis of its X-ray analysis. Their cytotoxic activities and anti-HIV-RT activities were evaluated.     

K3PO4-promoted Cyclopropanation of Electron-deficient Alkenes with 2-Bromo-1,3-propanedione Compounds

An easy and efficient method for the synthesis of multisubstituted cyclopropane derivatives from electron-deficicent alkenes with 2-bromo-1,3-propanedione compounds was described. For this method, ethyl α-cyanocinnamate derivatives 1 and β,β-dicyanostyrene derivatives 4 can all smoothly react with 2-bromo-1,3-propanedione compounds 2 to afford the corresponding multisubstituted cyclopropane derivatives 3 and 5 in good to excellent yields(up to 100%) promoted by anhydrous K₃PO₄ in DMF at room temperature, respectively. A possible mechanism of this reaction was proposed. Structures of all the products were confirmed by ¹H NMR, ¹³C NMR and HRMS.     

Cytotoxic triterpenoid saponins from Ardisia pusilla

A new triterpenoid saponin,3-O-{β-D-xylopyranosyl-(1→2)-β-D-glucopyranosyl-(1→4)-[β-D-ghcopyranosyl-(1→2)]-α-L-arabinopyranosyl }-3β,16α,28α-trihydroxy-1313,28-epoxy-oleanan-30-al(ardipusilloside Ⅲ,1),together with two known sapo-nins,ardisiacrispins A(2)and B(3),were isolated from the whole plants ofArdisia pusilla A.DC.Their structures were elucidated by extensive spectral analysis and chemical evidences.Saponins 1 and 3 exhibited significant cytotoxicity against human glioblastoma U251MG cells.     

Two new steroidal glycosides from Ophiopogon japonicus

Two new C27-steroidal glycosides were isolated from the fibrous roots of Ophiopogon japonicus. The spectral analysis and chemical evidence revealed their chemical structures to be （25R）-spirost-5,14-dien-3β-yl-O-α-L-rhamnopyranosyl-（1 → 2）-β-D- xylopyranosyl-（1 → 4）-β-D-glucopyranoside （1） and ophiogenin 3-O-β-D-glucopyranoside （2）.     

Synthesis,structural characterization and solubility of 2-(1-substituted-1,11-undecylidene)-5-arylimino-△~3 -1,3,4-thiadiazolines

A series of novel 2-(1-substituted-1,11-undecylidene)-5-arylimino-△~3-1,3,4-thiadiazolines(4) were synthesized and their structure was characterized by ~1H NMR,~(13)C NMR and elemental analysis.Their solubility in both polar and non-polar solvents is significantly improved owing to the introduction of ethyl or methylthio group at cyclododecyl ring as compared with parent compounds[1,2-(1,11-undecylidene)-5-arylimino-△~3-1,3,4-miadiazolines].However,their fungicidal activity against Rhizoctonia solani is ...     

Synthesis and cytotoxicity of 28-carboxymethoxy lupane triterpenoids. Preference of 28-O-acylation over 28-O-alkylation of betulin by ethyl bromoacetate

28-Carboxymethoxy lupane tritepenoids 3 and 4 were synthesized by alkylation of betulin with the THP protected 2-hydroxyethyl iodide followed by oxidation and reduction.Direct reaction of betulin (5) or betulone (10) with ethyl bromoacetate led to 28-O-acylation, instead of 28-O-alkylation.The targeted compounds 3 and 4 were not cytotoxic at the highest concentrationtested (75 mmol/L), suggesting that elongation of the chain length at the 28-position in both betulinic acid (1) and betulonic acid (2)was detrimental to the cytotoxicity.The acylation products 28-O-bromoacetates (8a, 8b and 11) and 28-O-methoxyacetate 13exhibited cytotoxicity against several cancer cell lines tested.     

薤中新的甾体皂苷类化学成分

从薤(Allium chinense G. Don)的乙醇提取物中分离得到6个新甾体皂苷类化合物, 通过波谱数据及理化性质分析, 鉴定其分别为5α-cholano-22,16-内酯-3-O-β-D-吡喃葡萄糖基-(1→2)-[β-D-吡喃葡萄糖基-(1→3)]-β-D-吡喃葡萄糖基(1→4)-β-D-吡喃半乳糖苷(1)、 6-酮-5α-cholano-22,16-内酯-3-O-β-D-吡喃木糖基-(1→4)-[α-L-吡喃阿拉伯糖基-(1→6)]-β-D-吡喃葡萄糖苷(2)、 (25R)-26-O-β-D-吡喃葡萄糖基-5α-呋喃甾烷-3β,26-二醇-3-O-β-D-吡喃葡萄糖基-(1→2)-[β-D-吡喃葡萄糖基-(1→3)]-β-D-吡喃葡萄糖基(1→4)-β-D-吡喃半乳糖苷(3)、 (25R)-6-酮-26-O-β-D-吡喃葡萄糖基-5α-呋喃甾烷-3β,22α,26-三醇-3-O-α-L-吡喃木糖基-(1→4)-β-D-吡喃葡萄糖苷(4)、 (25R)-6-酮-5α-呋喃甾烷-3β,22α,24β,26-四醇-3-O-β-D-吡喃木糖基-(1→4)-[α-L-吡喃阿拉伯糖基-(1→6)]-β-D-吡喃葡萄糖苷(5)和(25R)-5α-呋甾-2α,3β,22α, 26-四醇-26-O-β-D-吡喃葡萄糖苷(6). 化合物1和2的皂苷元骨架在天然产物中首次分离得到. 选用H₂O₂诱导PC12细胞神经氧化损伤模型, 初步考察了6种新的呋甾型化合物的抗氧化活性, 实验结果表明, 化合物3对由H₂O₂诱导的细胞氧化损伤有显著的保护效果.     

Two new phenolic glycosides from the aerial parts of Androsace umbellata

Two new phenolic glycosides,2-hydroxy-4-O-β-D-glucopyranosylphenylacetic acid methyl acetate(1) and 2-hydroxy-4-O-β-D-glucopyranosylphenylacetic acid(2) were isolated from the aerial parts of Andwsace umbellata.Their structures were elucidated by spectral techniques.     

A new C21 steroid glycoside from Marsdenia tenacissima

A new C21 steroid glycoside,11α-O-tigloyl-12-β-O-acetyl tenacigenin B 3-O-β-D-glucopyranosyl-（1→4）-β-D-glucopyr- anosyl-（1→4）-3-O-methyl-6-deoxy-β-D-allopyranosyl-（1→4）-β-D-oleandropyranoside（1）,named tenacissoside N was isolated from the stems of Marsdenia tenacissima.The structure of the glycoside was identified by HR-ESI-MS and NMR spectra.     

A new cycloartane nortriterpenoid from Quercus variabilis Blume

The leaves and stems of Quercus variabilis Blume afforded a new cycloartane nortriterpenoid,3α-acetyloxy-4α,14α-dimethyl-9β, 19-cycloergost-24-oic acid(1),along with five known compounds(2-6).The structure of 1 was elucidated by 1D and 2D NMR and mass spectroscopy.     

Two new glycosides from the seeds of Cassia obtusifolia

Two new glycosides,nor-rubrofusarin-6-O-β-D-(6′-O-acetyl)glucopyranoside(1) and 1-desmethylaurantio-obtusin-2-O-β-D-glucopyranoside (2) were isolated from the seeds of Cassia obtusifolia and their structures were established by chemical and spectral evidences.     

Unexpected Products from the Reaction of Naphthols with Cholesterol Catalysed by Montmorillonite K 10

Under catalysis of montmorillonites, arenes could be cholesterylated by cholesterol (1) via a Friedel-Crafts alkylation.¹ When phenols were employed as substrates for that reaction, aryl cholesteryl ethers were obtained instead of aryl cholestenes.² However, β-naphthol (2a) and α-naphthol (2b) gave obviously different products. We report here the identification of these unexpected products from the reaction of 2 with 1 catalysed by montmorillonite K 10.     

A new glycoside from the leaves of Neoalsomitra integrifoliola

A new ionone glycoside （6R,9R）-blumenyl α-L-rhamnopyranosyl-（1 → 6）-β-D-gluco-pyranoside （1）, together with a new natural product 2-methoxyl-4-trans-pmpenyl-phenol α-L-rhamnopyranosyl-（1 → 6）-β-D-glucopyranoside （2）, was isolated from the leaves ofNeoalsomitra integrifoliola. Their structures were elucidated by chemical and spectral analysis. Compound 1 showed weak anti-inflammatory and low-level antioxidant activities.     

Heterocyclic benzoxazole-based liquid crystals

The synthesis, characterization, and mesomorphic properties of a new type of heteronuclear compounds 1a-c and a Pd complex 1d derived from benzoxazole as the core group are reported. These compounds were prepared by the ring closure reaction of 4-alkoxybenzoic acid 4-[(4-alkoxy-2-hydroxyphenylimino)methyl]phenyl esters 6 in the presence of lead(IV) acetate. All the compounds were characterized by ¹H and ¹³C NMR spectroscopies and elemental analysis. The phase behaviour of these mesogenic compounds was characterized and studied by differential scanning calorimetry and polarizing optical microscopy. All the compounds 1a exhibited nematic (N) and/or smectic C (SmC) phases, as expected for rod-like molecules; however, the compounds 1b and 1c exhibited crystal phases. For those compounds 1a having shorter carbon chains (n = 1, 3, 4) nematic phases were observed, whereas for compounds having longer carbon chains (n = 6, 7, 8, 10, 12, 14) smectic C behaviour was also observed at lower temperatures. The greater aspect ratio (l/d) of compounds 1a compared with 1b and 1c was found to be required for the observation of liquid crystallinity. The fluorescent properties of these compounds were also examined. All λ_max peaks of the absorption and photoluminescence spectra of compounds 1a-1c occurred at c. 316-322 nm and 371-382 nm, respectively. The quantum yields of some compounds were relatively low, and also slightly solvent-dependent.     

Two new steroidal glucosides from Ophiopogon.japonicus （L.f.） Ker-Gawl

Two new steroidal glucosides, 26-O-β-D-glucopyranosyl （25S）-furost-5-ene-1β,3β,22α,26-tetraol l-O-β-D-xylopyranosyl- （1 → 3）-[α-h-rhamnopyranosyl-（1 → 2）]-[β-D-fueopyranoside and （25R） spirost-5-ene-3β,14α-diol-3-β-O-β-L-rhanmopyranosyl- （1 → 2）-[β-D-xylopyranosyl（1 → 4）]-[-β-D-glucopyranoside, were isolated from the Ophiopogon japonicus （L.f.） Ker-Gaw. Their structures were elucidated by spectroscopic methods.