中药龟板提取物化学成分及其调控鼠骨髓间充质干细胞(rMSCs)增殖活性的实验研究

中药龟板提取物浸膏经硅胶柱层析, 用石油醚-乙酸乙酯作洗脱剂, 梯度洗脱, 得到16个组分; 采用MTT法和流式细胞技术研究了它们对鼠骨髓间充质干细胞(rMSCs)的增殖作用, 实验结果显示组分Ts-12具有促进rMSCs增殖的作用(p＜0.05), 而组分Ts-4则表现出抑制rMSCs增殖的作用(p＜0.05), 其它样品对rMSCs的增殖作用不显著(p＞0.05), 不具统计学意义. 采用了GC-MS分析各组分化学成分, 并用HPLC和9个标准物质鉴定确证了组分Ts-12中含有十六酸甲酯(S-1)、十六酸乙酯(S-3)、十八酸甲酯(S-4)和甾醇(S-7)以及十四酸甾醇酯(S-8), 组分Ts-4主要含有十八酸(S-5). 对标准品也采用了MTT法和流式细胞仪研究了它们对rMSCs的增殖作用, 结果表明十四酸甾醇酯和十六酸甲酯具有促进rMSCs增殖的作用, 而十八酸具有抑制作用.     

New bioactive constituents from eleutherine americana

Three new constituents were isolated from Eleutherine americana Merr. et K. Heyne (hong-cong) by means of silica gel, octadecyl silane (ODS) column chromatography and high-performance liquid chromatography (HPLC). They were identified as (1) 9,9′-dihydroxy-8,8′-dimethoxy-1′-dimethyl-1H, 1H′-[4,4′]bis[naphtha[2,3-c] funanyl]-3,3′-dione; (2) 6,8-dihydroxy-3,4-dimethoxy-1-methyl-anthraquin-one-2-carboxylic acid methyl ester; and (3) 2-acetyl-3,6,8-trihydroxy-1-methyl anthraquinone by the physico-chemical properties and spectral data, respectively. All three compounds showed weak activities against the growth of Pyricularia oryzea. The minimum morphological deformation concentration (MMDC) was 145.8, 50.2, and 124.8 μg/mL. Additionally, (2) also inhibited the proliferation of human erythroleukemia cancer cell line K562 with IC₅₀ value of 49.1 μg/mL. __________ Translated from Chemical Journal of Chinese Universities, 2005, 26(11) (in Chinese)     

Fatty acid composition of two Athamanta turbith subspecies

The fruit oils of Athamanta turbith ssp. hungarica and Athamanta turbith ssp. haynaldii were obtained by Soxhlet extraction using petroleum ether. The fatty acid composition of oils was determined by GC in the methyl ester form. Considering the composition and content of fatty acids, the examined oils were very similar. Petroselinic acid was the principal one (45.6 and 46.2%, respectively), followed by a significant amount of linoleic acid (26.9 and 29.1%, respectively). In both oils, myristic, pentadecanoic, palmitic, palmitoleic, stearic, petroselinic, oleic, linoleic, α-linolenic, arachidic, and behenic acid were identified. Lignoceric acid was detected only in A. turbith ssp. hungarica oil. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 319–320, July–August, 2006.     

Synthesis of new spiro compounds containing a carbamate group

1,3-Dipolar cycloaddition to methyl 4-[2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)-1-oxoethyl]-phenylcarbamate of diazomethane in chloroform-diethyl ether and of 3,4-dimethoxybenzonitrile oxide generated from the corresponding aldehyde oxime by the action of N-chlorobenzenesulfonamide sodium salt (Chloramine B) in boiling ethanol gave, respectively, methyl 4-(2-oxo-1′,5′-dihydro-1H-spiro[indole-3,4′-pyrazol]-3′-ylcarbonyl)phenylcarbamate and methyl 4-[3′-(3,4-dimethoxyphenyl)-2-oxo-1H,4′H-spiro[indole-3,5′-isoxazol]-4′-ylcarbonyl]phenylcarbamate. The condensation of methyl 4-[2-(2-oxo-2,3-dihydro-1H-indol-3-ylidene)-1-oxoethyl]phenylcarbamate with hydrazine hydrate in ethanol afforded methyl 4-(2-oxo-1,2,2′,4′-tetrahydrospiro[indole-3,3′-pyrazol]-5′-yl)phenylcarbamate.     

Synthetic transformations of higher terpenoids: XXIV. Synthesis of cyanoethyl derivatives of lupane triterpenoids and their transformation into 1,2,4-oxadiazoles

Cyanoethylation of lupane triterpenoids was performed. Amide oximes of 3β-O-(2-cyanoethyl)-betulinic acid methyl ester and 3β-O-acetyl-28-O-(2-cyanoethyl)betulin and the corresponding O-[2-(1,2,4-oxadiazol-3-yl)ethyl] lupane derivatives were obtained.     

Protonation Switching to the Least‐Basic Heteroatom of Carbamate through Cationic Hydrogen Bonding Promotes the Formation of Isocyanate Cations

We found that phenethylcarbamates that bear ortho‐salicylate as an ether group (carbamoyl salicylates) dramatically accelerate O?C bond dissociation in strong acid to facilitate generation of isocyanate cation (N‐protonated isocyanates), which undergo subsequent intramolecular aromatic electrophilic cyclization to give dihydroisoquinolones. To generate isocyanate cations from carbamates in acidic media as electrophiles for aromatic substitution, protonation at the ether oxygen, the least basic heteroatom, is essential to promote C?O bond cleavage. However, the carbonyl oxygen of carbamates, the most basic site, is protonated exclusively in strong acids. We found that the protonation site can be shifted to an alternative basic atom by linking methyl salicylate to the ether oxygen of carbamate. The methyl ester oxygen ortho to the phenolic (ether) oxygen of salicylate is as basic as the carbamate carbonyl oxygen, and we found that monoprotonation at the methyl ester oxygen in strong acid resulted in the formation of an intramolecular cationic hydrogen bond (>C?O⁺?H???O<) with the phenolic ether oxygen. This facilitates O?C bond dissociation of phenethylcarbamates, thereby promoting isocyanate cation formation. In contrast, superacid‐mediated diprotonation at the methyl ester oxygen of the salicylate and the carbonyl oxygen of the carbamate afforded a rather stable dication, which did not readily undergo C?O bond dissociation. This is an unprecedented and unknown case in which the monocation has greater reactivity than the dication.     

Synthesis of double hydrophilic graft copolymer containing poly(ethylene glycol) and poly(methacrylic acid) side chains via successive ATRP

A well‐defined double hydrophilic graft copolymer, with polyacrylate as backbone, hydrophilic poly(ethylene glycol) and poly(methacrylic acid) as side chains, was synthesized via successive atom transfer radical polymerization followed by the selective hydrolysis of poly(methoxymethyl methacrylate) side chains. The grafting‐through strategy was first used to prepare poly[poly(ethylene glycol) methyl ether acrylate] comb copolymer. The obtained comb copolymer was transformed into macroinitiator by reacting with lithium diisopropylamine and 2‐bromopropionyl chloride. Afterwards, grafting‐from route was employed for the synthesis of poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methoxymethyl methacrylate) amphiphilic graft copolymer. The molecular weight distribution of this amphiphilic graft copolymer was narrow. Poly(methoxymethyl methacrylate) side chains were connected to polyacrylate backbone through stable C? C bonds instead of ester connections. The final product, poly[poly(ethylene glycol) methyl ether acrylate]‐g‐poly(methacrylate acid), was obtained by selective hydrolysis of poly(methoxymethyl methacrylate) side chains under mild conditions without affecting the polyacrylate backbone. This double hydrophilic graft copolymer was found be stimuli‐responsive to pH and ionic strength. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4056–4069, 2008     

Synthetic transformations of higher terpenoids: XXIII. Synthesis of diterpenoid-based dihydroisoindolones

Vilsmeier-Haak reaction of phlomisoic acid methyl ester gave a mixture of 15- and 16-formyllabdanoids. In addition, methyl 2-formyldodecahydrophenanthro[1,2-b]furan-6-carboxylate was isolated, and its structure was determined by X-ray analysis. Reductive amination of 16-formyllabdanoid with benzylamine or α-amino acid methyl esters led to the formation of labdanoid furfurylamines which reacted with maleic anhydride to produce N-substituted 4-oxo-10-oxa-3-azatricyclo[5.2.1.0^1,5]dec-8-ene-6-carboxylic acids. Acylation of labdanoid furfurylamines with (E)-but-2-enoyl chloride afforded the corresponding unsaturated amides which were converted into 10-oxa-3-azatricyclo[5.2.1.0^1,5]dec-8-en-4-ones via intramolecular Diels-Alder reaction. Treatment of the oxa adducts with boron trifluoride-diethyl ether complex gave dihydroisoindol-1-one derivatives containing a diterpene fragment.     

Clionasterol Glucoside and Acylated Clionasterol Glucosides from Oplismenus burmannii

A new clionasterol glucoside, clionasterol‐[(1'→3α)‐O‐β‐D]‐glucopyranoside ( 1 ), a new acylated clionasterol glucoside, clionasterol‐[6'‐O‐acyl‐(1'→3β)‐O‐b‐D]‐glucopyranoside ( 2 ) and clionasterol ( 3 ) were isolated from the aerial parts of Oplismenus burmannii. The nature and length of fatty acid acyl chains in 2 was identified by alkaline methanolysis of compound 2 . The aglycone fraction on GC‐MS analysis showed three peaks in GC at t_R 49.86 (82.1%), 51.13 (13.3%) and 56.53 (4.6%) min, which were characterized as arachidic acid methyl ester ( a ) oleic acid methyl ester ( b ) and 12‐methyltetradecanoic acid methyl ester ( c ) respectively. Thus 2 was characterized as a mixture of three new compounds, clionasterol‐[6'‐O‐eicosanoyl‐(1'→3β)‐O‐β‐D]‐glucopyranoside ( 2a ), clionasterol‐[6'‐O‐(8Z)‐octa‐deca‐9‐enoyl‐(1'→3β)‐O‐β‐D]‐glucopyranoside ( 2b ) and clionasterol‐[6'‐O‐(12‐methyltetradecanoyl)‐(1'→3β)‐O‐β‐D]‐glucopyranoside ( 2c ).     

Synthesis of hexahydro[1,4]diazocino[7,8,1-<Emphasis Type="Italic">jk</Emphasis>]carbazoles and 1-methoxy-9-(β-vinylethylamino)ethylcarbazoles

3-Ethylhexahydropyrazino[3,2,1-jk]carbazole is converted into hexahydro[1,4]diazocino[7,8,1-jk]carbazoles by the action of methyl propiolate and acetylacetylene in acetonitrile and into 1-methoxy9-(β-vinylethylamino)ethylcarbazoles by the action of acetylenedicarboxylic ester and methyl propiolate in methanol. 3-Benzyl-substituted pyrazinocarbazole does not react with alkynes.     

Formation of diethylene glycol as a side reaction during production of polyethylene terephthalate

Polymers of poly(ethylene terephthalate) (PET) always contain a certain amount of incorporated diethylene glycol (DEG), substituting the incorporated glycol. DEG is formed in a side reaction during the ester interchange of dimethyl terephthalate (DMT) with ethylene glycol or during direct esterification of terephthalic acid with ethylene glycol, and to a smaller extent during the polycondensation of the low-molecular material. DEG is formed via an unusual type of reaction: ester + alcohol → ether + acid. Some evidence of this type of reaction is given by the formation of dioxane in low molecular PET and of methyl Cellosolve and methyl carbitol during the ester interchange of DMT with ethylene glycol and diethylene glycol, respectively. The strongest support for this type of reaction, however, was obtained from kinetic data. Polyesters of low molecular weight with OH group contents ranging from 3 to 0.5 mole/kg were heated at 270°C in sealed tubes for 1–7 hr. The kinetic equation for the proposed reaction is: d[DEG]/dt = k[OH] [ester]. With the aid of one rate constant the formation of DEG in all esters could be described.     

SEP-PAK Preparative Chromatography: Use in Radiopharmaceutical Synthesis

Abstract

The use of SEP-PAK^R C₁₈ cartridges for the isolation and purification of radiopharmaceuticals, labeled with the 20.4 minute half-life radionuclide carbon-11, is reported. Synthesis and SEP-PAK preparative chrotmatographic purification of [1-¹¹C]palmitic acid, [¹¹C-methyl]benzyl methyl ether, [1-¹¹C]butan-1-ol, and [1-¹¹C]pyruvic acid are described. The use of SEP-PAK C₁₈ cartridges has allowed development of rapid and remote methods for handling of high amounts (> 100 mCi) of radioactive products.     

Intramolecular [3+2] cycloaddition reaction of α,β-enoate derivatives having allylsilane parts: 1,1′-biphenyl-2,2′-di(triflyl)amide (BIPAM)+2Me2AlCl as a novel Lewis acid

The bidentate Lewis acid generated by mixing 1,1′-biphenyl-2,2′-di(triflyl)amide (BIPAM) and 2 M equiv of Me₂AlCl can efficiently promote the intramolecular [3+2] cycloaddition reaction of α,β-enoate derivatives having ester tether linking α,β-unsaturated ester and allylsilane parts.     

Some condensations of methyl 4-acetylphenylcarbamate

Condensation of methyl 4-acetylphenylcarbamate with isatin in the presence of diethylamine afforded methyl 4-[(3-hydroxy-2-oxo-2,3-dihydro-1H-indol-3-yl)acetyl]phenylcarbamate which was converted into the corresponding chalcone on heating in glacial acetic acid in the presence of hydrochloric acid. 1,3-Dipolar cycloaddition to that chalcone of azomethine ylide generated from 2-phenacylisoquinolinium bromide by the action of triethylamine gave methyl 4-(3′-benzoyl-2-oxo-1′,2,2′,3,3′,10b′-hexahydro-1H-spiro-[indole-3,1′-pyrrolo[1,2-a]isoquinolin]-2′-ylcarbonyl)phenylcarbamate. Condensation of 2-hydroxy- and 2,4-dihydroxybenzaldehydes with methyl 4-acetylphenylcarbamate in the presence of gaseous hydrogen chloride resulted in the formation of chromenium salts with a methoxycarbonylaminophenyl fragment on the C² atom in the heteroring.     

Synthesis and cytotoxic activity of derivatives of 6<Emphasis Type="Italic">Z</Emphasis>-acetylmethylenepenicillanic acid <Emphasis Type="Italic">tert</Emphasis>-butyl ester

The sulfoxide of 6Z-[2-(methoxyimino)propylidene]penicillanic acid tert-butyl ester and the sulfones of 6Z-[2-(hydroxyimino-, methoxyimino-, benzyloxyimino-, 2-bromo- and 4-bromobenzyloxyimino)-propylidene]penicillanic acid in the syn and anti forms have been synthesized by the condensation of the sulfoxide and sulfone of 6Z-acetylmethylenepenicillanic acid tert-butyl ester with hydroxylamine, methoxyamine, benzyloxyamine, 2-bromo- and 4-bromobenzyloxyamines. The syn and anti isomers of 3Z-(2-methoxyiminopropylidene)-4R-(benzothiazolyl-2-dithio)-2-oxoazetidinyl-1R-(2-propenyl)acetic acid tert-butyl ester were obtained by opening of the thiazolidine ring in 6Z-[2-(methoxy-imino)propylidene]-1-oxopenicillanic acid tert-butyl ester with 2-mercaptobenzothiazole. The 3Z-(2-methoxyiminopropylidene)-4R-(methylsulfonyl)-2-oxoazetidinyl-1-(2-propylidene)acetic acid tert-butyl ester was synthesized by the interaction of 1,8-diazobicyclo[5.4.0]undec-7-ene and methyl iodide with 6Z-[2-(methoxyimino)propylidene]-1,1-dioxopenicillanic acid tert-butyl ester. A dependence of the cytotoxic effect in relation to cancer and normal cells in vitro on the structure of the substituent in position 6 and the syn and anti isomerism of the oxyimino group was established for the synthesized compounds.     

Chiral rhodium carboxylates as asymmetric hydrogenation catalysts

The comparative catalytic activities of a few chiral rhodium carboxylato complexes in combination with chiral and achiral phosphines are described. In the hydrogenation of α-acetamidocinnamic acid and its methyl ester, differences are observed in turnover numbers and enantioselectivities. Diastereomeric interactions between chiral carboxylato and chiral phosphine moieties resulting in different rates are clearly seen. Arrhenius plots of (+) and (-) DIOP [DIOP = 2,3 isopropylidene 2,3 dihydroxy-1,4bis (diphenylphosphino) butane] with rhodium (-) mandalato complex give markedly different activation energies.     

Reaction of [α-(trimethylsilyl)benzyl]ferrocenes with α-ferrocenylbenzyl cations

Although methanolysis of [α-(trimethylsilyl)benzyl]ferrocene (I) and [p-methyl-α-(trimethylsilyl)benzyl]ferrocene (II) in the presence of anhydrous ferric chloride merely gave α-ferrocenylbenzyl methyl ether (III) and p-methyl-α-ferrocenylbenzyl methyl ether (IV), respectively, acid-catalyzed methanolysis of (I) and (II) in the presence of an equimolar amount of (III) or (IV) afforded 1,2-diferrocenyl-l,2-diarylethanes. It is suggested that one electron oxidation of [α-(trimethylsilyl)benzyl]ferrocene by α-ferrocenylbenzyl cation generated from α-ferrocenylbenzyl methyl ether, and subsequent methanolysis of the resulting substituted ferricenium ion may occur to give the two species of α-ferrocenylbenzyl radical, which in turn undergo an approximately statistical coupling.     

Effect of Ceramide on Mesenchymal Stem Cell Differentiation Toward Adipocytes

Proinflammatory cytokines such as tumor necrosis factor (TNF) α are well known to inhibit adipocyte differentiation. TNF-α triggers ceramide synthesis through binding of TNF-α to its p55 receptor. Therefore, ceramide is implicated in many of the multiple signaling pathways initiated by TNF-α. In breast tissue engineering, it is important to know how to modulate adipocyte differentiation of the stem cells with exogenous additives like ceramide in vitro. We hypothesized that stem cell adipogenesis could be retained in TNF-α-treated preadipocytes in which ceramide synthesis was blocked and that exogenous ceramide could inhibit adipocyte differentiation. We first studied the effect of ceramide synthase inhibitor, Fumonisin B2, on the adipogenesis of murine mesenchymal stem cells (D1 cells), treated with TNF-α. We then studied the effect of specific exogenous C6-ceramide on D1 cell viability and differentiation. It was found that 1 ng/ml of TNF-α significantly inhibited D1 cell adipogenesis. Cells treated with 5 μM of Fumonisin B2 were able to undergo adipogenesis, even when treated with TNF-α. High concentrations of exogenous C6-ceramide (>50 μM) had an inhibitory effect, not only on the pre-confluent proliferation of the D1 cells but also on the post-confluent cell viability. High concentrations of C6-ceramide (>50 μM) also inhibited mitotic clonal expansion when D1 cell differentiation was induced by the addition of an adipogenic hormonal cocktail. C6-ceramide at low concentrations (10–25 μM) inhibited lipid production in D1 cells, demonstrated by decreased levels of both total triglyceride content and specific fatty acid composition percentages. Genetic expression of peroxisome proliferator-activated receptor (PPAR) γ and aP2 in D1 cells was reduced by C6-ceramide treatment. CCAAT/enhancer-binding protein (C/EBP) β levels in D1 cells were reduced by C6-ceramide treatment during early differentiation; PPARγ and aP2 protein levels were reduced at terminal differentiation. C6-ceramide at lower concentrations also decreased lipid accumulation of differentiating D1 cells. Our results suggest that ceramide synthase inhibitor retains the adipogenic potential of TNF-α-treated mesenchymal stem cells, while exogenous ceramide at lower concentrations inhibit the adipogenesis of mesenchymal stem cells. Ceramide, therefore, could be a modulator candidate in breast tissue engineering strategies.     

Pd(II)-catalyzed vinylic polymerization of norbornene and copolymerization with norbornene and copolymerization with norbornene carboxylic acid esters

The vinylic polymerization of norbornene and its copolymerization with norbornene carboxylic acid methyl esters were investigated. Norbornene was polymerized by us using di-μ-chloro-bis-(6-methoxybicyclo[2.2.1]hept-2-ene-endo-5σ,2π)-palladium(II) as catalyst. The polymerization time can be decreased by a factor of 100000 by activation of the catalyst with methylaluminoxane (MAO). With this palladium catalyst activated by MAO, 140 t of norbornene can be polymerized per mol palladium per h. This catalyst system was much more active than [Pd(CH₃CN)₄](BF₄)₂ ( I ). The polymerization of norbornene by (6-methoxybicyclo[2.2.1]hept-2-ene-endo-5σ,2π)-palladium(II) tetrafluoroborate was also possible but it was not as fast as the polymerization by Pd catalysts activated with MAO. We were also able to obtain copolymers of norbornene and 5-norbornene-2-carboxylic acid methyl ester (exo/endo = 1/4 or 2/3) containing between 15 and 20 mol-% ester units. The copolymerization of norbornene and 2-methyl-5-norbornene-2-carboxylic acid methyl ester (exo/endo = 7/3) was faster than the copolymerization mentioned before. In contrast the homopolymerization of 2-methyl-5-norbornene-2-carboxylic acid methyl ester was 10 times slower than that of 5-norbornene-2-carboxylic acid methyl ester (exo/endo = 1/4).     

Organic Base‐Catalyzed Stereoselective Isomerizations of 4‐Hydroxy‐4‐phenyl‐but‐2‐ynoic Acid Methyl Ester to (E)‐ and (Z)‐4‐Oxo‐4‐phenyl‐but‐2‐enoic Acid Methyl Esters

We have developed a 1,4‐diazabicyclo[2.2.2]octane (DABCO)‐catalyzed isomerization of 4‐hydroxy‐4‐phenyl‐but‐2‐ynoic acid methyl ester to (E)‐4‐oxo‐4‐phenyl‐but‐2‐enoic acid methyl ester and an N,N‐diisopropylethylamine‐catalyzed isomerization of the same substrate to (Z)‐4‐oxo‐4‐phenyl‐but‐2‐enoic acid methyl ester.