High-Yield Syntheses of Tetra-O-benzyl-α-D-glucopyranosyl bromide and Tetra-O-pivaloyl-α-D-glucopyranosyl bromide and their Advantage in the Koenigs-Knorr Reaction

Summary. Several improved approaches for the preparation of tetra-O-benzyl-α-D-glucopyranosyl bromide and tetra-O-pivaloyl-α-D-glucopyranosyl bromide are discussed. The importance of these compounds, which are useful glycosyl donors, was demonstrated by successful preparation of cholesteryl glucopyranosides in an almost neutral medium without the formation of orthoesters. In addition, accurate ¹H and ¹³C NMR resonance assignments of the synthesized cholesteryl glycosides were performed by 2D NMR spectroscopy.     

柘树根多糖的分离纯化及结构表征

以柘树[Cudrania tricuspidata(Carr.) Bur.]的根为材料, 经热水抽提、木瓜蛋白酶-Sevag法除蛋白、乙醇沉淀和DEAE-Sephadex A-50凝胶柱层析分离纯化, 得到一种水溶性的柘树根多糖(CPS-0). 采用HPLC、糖基组成分析、甲基化分析、GC、GC-MS、NMR(1H NMR, 13C NMR及HMQC)、元素分析、UV和IR等技术对CPS-0的纯度、性质、组成和结构进行表征. 结果表明, CPS-0仅含葡萄糖, 分子量为4.6×103, 主链由1,4-连接的α-D-葡萄糖残基组成, 其侧链由末端及1,4-连接的葡萄糖残基构成, 取代于主链分支点葡萄糖的6位, 平均每10个葡萄糖残基组成的重复单元中含有1个分支.     

Stereospecific mannosylations of myo -inasitol: Synthesis of manno- myo -inositol fragment of Mycobacterium tuberculosis

Methyl iodide activated stereospecific α-mannosylations utilising 2-pyridyl-1-thiomannopyranoside derivatives (2,3,4) as donors and suitably protected myo-inositol derivatives (1,25,27,29) as acceptors to prepare 2-0-α-D-mannopyranosyl-6-[O-α-D-mannopyranosyl-(1–6)-O-α-D-mannopyranosyl-(l-6)-O-α-D-mannopyranosyl]-D-myo-inositol derivative (31) is described. IICT Commun. No. 3355     

High-Yield Syntheses of Tetra-O-benzyl-α-D-glucopyranosyl bromide and Tetra-O-pivaloyl-α-D-glucopyranosyl bromide and their Advantage in the Koenigs-Knorr Reaction

Several improved approaches for the preparation of tetra-O-benzyl-α-D-glucopyranosyl bromide and tetra-O-pivaloyl-α-D-glucopyranosyl bromide are discussed. The importance of these compounds, which are useful glycosyl donors, was demonstrated by successful preparation of cholesteryl glucopyranosides in an almost neutral medium without the formation of orthoesters. In addition, accurate ¹H and ¹³C NMR resonance assignments of the synthesized cholesteryl glycosides were performed by 2D NMR spectroscopy.     

An easy access to a 3,6-branched mannopentaoside bearing one terminal [1-<Superscript>13</Superscript>C]-labeled <Emphasis Type="SmallCaps">D</Emphasis>-mannopyranose residue

Methyl 2,4-di-O-benzoyl-α-D-mannopyranoside was used as a key intermediate in the synthesis of 3,6-branched mannopentaoside bearing one terminal D-[1-¹³C]mannopyranose residue, viz., methyl 6-O-[3,6-di-O-(α-D-mannopyranosyl)-α-D-mannopyranosyl)-3-O-{α -D-[1-¹³C]mannopyranosyl}-α-D-mannopyranoside. Dedicated to Academician N. K. Kochetkov on the occasion of his 90th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1250–1255, May, 2005.     

Polar steroidal compounds from the Far-Eastern starfish <Emphasis Type="Italic">Lethasterias fusca</Emphasis>

Nine steroidal compounds including three new steroidal glycosides, viz., sodium (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol 15-sulfate (fuscaside A), (24S)-3,24-di-O-(β-D-xylopyranosyl)-5α-cholestane-3β,6β,8,15α,24-pentol (fuscaside B), and (22E,24R)-24-O-(β-D-xylopyranosyl)-5α-cholest-22-ene-3β,6α,8,15β,24-pentol (desulfated minutoside A); three previously known glycosides, viz., distolasterosides D₁ and D₂ and pycno-podioside A; two previously known polyhydroxysteroids, viz., 5α-cholestane-3β,6α,8,15β,16β,26-hexaol and 5α-cholestan-3β,4β,6α,7⇇8,15β,16β,26-octol; and the known sodium 24,25-dihydro-marthasterone 3-sulfate were isolated from the Far-Eastern starfish Lethasterias fusca. The structures of these compounds were elucidated by NMR spectroscopy and mass spectrometry. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 196–200, January, 2008.     

Mild Pfitzner—Moffat oxidation of the (1→3)-β-D-glucan from Saccharomyces cerevisiae

The structure of the cell wall glucan isolated from the industrial strain of Saccharomyces cerevisiae was characterized as to be composed of a linear (1→3)-β-D-glucan chain with single β-D-glucopyranosyl residues attached to every ninth backbone unit by (1→6)-glycosidic linkages. Mild oxidation of this β-D-glucan with a dimethyl sulfoxide—acetic anhydride reagent yielded an “oxidized” glucan with aldehyde groups introduced at C-6 and carbonyl oxygens located at C-2 and C-4 of the glucopyranosyl rings. The conversion of the oxidized glucan into the polyoxime was used to study the progress of oxidation and to establish the carbonyl groups distribution in this new reactive polysaccharide derived from baker’s yeast cell wall.     

Polysaccharides of Fabaceae. I. Galactomannan of Astragalus sericeocanus seeds

Galactomannan (yield 3.58% of seed mass) of molecular weight 876 kDa was isolated from seeds of Astragalus sericeocanus Gontsch. (Fabaceae). Its solutions had high viscosity [η], 764.6 mL/g, and optical density [α]_D +65.3°. The polysaccharide consisted of galactose and mannose in molar ratio 1:1.58. The main chain of the galactomannan macromolecule was constructed of 1,4-β-D-mannopyranose units, 63% of which were substituted at C-6 by single α-D-galactopyranose units. ¹³C NMR spectroscopy established that the galactomannan contained units of differently substituted galactose mannobiose units: Man-Man, (Gal)Man-Man, and/or Man-Man(Gal) in addition to (Gal)Man-Man(Gal), the ratio of which was 0.15:0.51:0.34. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 555–557, November–December, 2008.     

27-Ald-triterpenoid saponins from Adina rubella

Four new triterpenoid saponins were isolated from the roots of Adina rubella Hance. They were characterized as adinaic acid 3β-O-[α-L-rhamnopyranosyl(l→2)-β-D-glucopyranosyl(l→2)-β-D-glucurono-pyranoside-6-O-methyl ester]-28-O-β-D)-glucopyranoside, adinaic acid 3β-O-[α-L-rham-nopyranosyl(l→2)-β-D-glucopyranosyl(l→2)-β-D-glucuronopyranoside-6-O-butyl ester]-28-O-β-D-glu-copyranoside, adinaic acid 3β-O-[β-D-glucopyranosyl(l→2)-β-D-glucopyranosyl]-(28→1)-β-D-gluco-pyranosyl(l→6)-β-D-glucopyranosyl ester, 27-hydroxyursolic acid 3β-O-[α-L-rhamnopyranosyl (l→2)-β-O-glucopyranosyl(l→2)-β-D)-glucuronopyranoside-6-O-methyl ester]-28-O-β-D)-glucopyranoside. Their structures were elucidated by spectral methods, especially with the aid of 2D NMR techniques. Their complete assignments of the 1H and 13C NMR signals were carried out.     

Comparison and characterization of polysaccharides from natural and cultured <Emphasis Type="Italic">Cordyceps</Emphasis> using saccharide mapping

Comparison and characterization of polysaccharides from natural and cultured Cordyceps on the basis of their chemical characteristics such as glycosidic linkages were performed for the first time using saccharide mapping. The results showed that polysaccharides from most of the natural and cultured Cordyceps had similar responses to enzymatic digestion. These polysaccharides mainly contained (1→4)-β-D-glucosidic linkages, and (1→4)-α-glucosidic, (1→6)-α-glucosidic, 1,4-β-D-mannosidic, as well as (1→4)-α-D-galactosiduronic linkages also existed in some polysaccharides. Especially, natural and cultured Cordyceps polysaccharides could be discriminated on the basis of high performance liquid chromatography profiles of pectinase hydrolysates, which is helpful to control the quality of polysaccharides from Cordyceps.     

Triterpene glycosides ofHedera canariensis III. Determination of the structures of glycosides L-F1, L-F2, and L-I2 from the leaves of Algerian ivy

The leaves of Algerian ivyHedera canariensis Willd. (Araliaceae) have yielded two new triterpene glycosides — caulophyllogenin 3-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranoside (L-F₂) and its 28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-gentiobiosyl ester (L-I₂) - and also the previously known hederagenin 3-O-α-L-rhamnopyranosyl-(1→2)-O-β-D-glucopyranoside (L-F₁). The structures of the glycosides were established on the basis of chemical transformations and¹H and¹³C NMR spectroscopy. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 777–781, November–December, 1998.     

Polysaccharides and sterols from green algae Caulerpa lentillifera and C. sertularioides

Sterols and polysaccharides of green alga Caulerpa lentillifera grown under laboratory conditions and in mariculture and polysaccharides of green alga C. sertularioides grown under natural conditions were studied. The sterol fraction consisted of C₂₇-C₂₉ steroidal alcohols with Δ⁵-unsaturation in the steroid core regardless of the growth conditions. The dominant (79.9%) steroid component of the sterol fraction was clionasterol. The water-soluble fraction of C. lentillifera grown under laboratory conditions was a mixture of 1,4-α- and 1,3-β-D-glucans and protein. The same fraction isolated from C. lentillifera grown in mariculture contained only protein. The water-soluble fraction of C. sertularioides grown under natural conditions contained 1,3;1,6-β-D-galactan sulfated at C2. The principal components of the base-soluble polysaccharide fractions from all algae samples were 1,4-α-D-glucans. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 5-8, January-February, 2009.     

短柄雪胆中的三萜葫芦素及其皂苷

从短柄雪胆的块根中分离得到了14个三萜葫芦素类化合物. 经波谱分析及化学方法鉴定了它们的结构, 其中有新化合物5个, 分别命名为短柄雪胆苷A～E (1～5), 以及肉花雪胆苷元A (6), 藤三七雪胆苷R8 (7), 肉花雪胆苷I (8), 肉花雪胆苷II (9), 肉花雪胆苷III (10), 雪胆甲素(11), 雪胆乙素(12), 雪胆甲素苷(13), 藤三七雪胆苷R1 (14)等9个已知化合物. 6是首次从自然界中得到的化合物.     

Polysaccharides from Fabaceae. IV. Galactomannan from <Emphasis Type="Italic">Gueldenstaedtia monophylla</Emphasis> seeds

Galactomannan (yield 1.73% of seed mass) with molecular weight 808 kDa was isolated from seeds of Gueldenstaedtia monophylla Fisch. (Fabaceae). Its solutions were typically highly viscous with [η] 664.7 mL/g and optically active with [α]_D +45.2°. It consisted of galactose and mannose in a 1:1.91 ratio. Physical chemical methods established that the principal chain of the polysaccharide consisted of 1,4-β-D-mannopyranose units substituted 50.1% in the C-6-position by single α-D-galactopyranose units and traces of 6-O-α-galactopyranosylgalactopyranose. The contents of mannobiose blocks substituted by galactose Man–Man, (Gal)Man–Man/Man–Man(Gal), and (Gal)Man–Man(Gal) in the galactomannan macromolecule were 23, 42, and 35%, respectively.     

Structure of the repeat unit of the Alteromonas addita type strain KMM 3600T O-specific polysaccharide

The O-specific polysaccharide of Alteromonas addita type strain KMM 3600T is constructed of trisaccharide repeat units containing L-rhamnose, D-glucose, and D-galactose. It was established that the O-specific polysaccharide consists of trisaccharide repeat units with the structure →3)-α-D-Galp-(1→3)-α-L-Rhap-(1→3)-α-D-Glcp-(1→ based on monosaccharide analysis, Smith degradation, PMR and ¹³C NMR spectroscopy, and two-dimensional COSY, HSQC, and HMBC. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 445–447, September-October, 2008.     

New triterpene glycoside from <Emphasis Type="Italic">Cyclamen adzharicum</Emphasis> tubers

Nine pure glycosides were isolated from total saponins of Cyclamen adzharicum Pobed. (Primulaceae). The total chemical structure of cyclamen F, 3β-O-[β-D-Xylp(1→2)]-[β-D-Glcp(1→2)]-(β-D-Glcp(1→4)-α-L-Arap)-16α-hydroxy-13,28-epoxy-30,30-dibutoxyolean, was elucidated using modern physicochemical and spectral methods (NMR, ¹H, ¹³C, HMBC, HMQC, DEPT, COSY, MS). A glycoside with the cyclamen F chemical structure has not been reported and, therefore, is a new organic compound.     

Synthesis, crystal structure, and thermal properties of N,N′-di(diethoxythiophosphoryl)-1,4-phenylenediamine

The title compound N,N′-di(diethoxythiophosphoryl)-1,4-phenyl-enediamine was synthesized by the reaction of diethoxythiophosphoryl chloride with p-phenylenediamine and characterized by elemental analysis, IR, and ¹H NMR spectra. Its crystal structure was determined by X-ray diffraction analysis and the thermal property was studied by TG analysis. The relative molecular weight of the title compound is 412.42. The crystal structure belongs to the orthorhombic, Pbca space group, with a = 0.86936(16) nm, b = 1.2787(2) nm, c = 1.8897(3) nm, β = 90°, V = 2.1006(7) nm³, Z = 8, Dc = 1.304 g/cm³, μ(Mo Kα) = 0.425 mm⁻¹, F(000) = 872, S = 1.052, the final R = 0.0628 and wR = 0.1860 for 1852 observed reflections with I>2σ(I). The X-ray diffraction analysis demonstrates that the crystal structure is centrosymmetric. The weak N-H⋯S intramolecular hydrogen bonds were observed to link the molecules into sheets. The TG analysis shows that the title compound has good thermal stability and char forming capability and its fire retardation for polyacrylonitrile reveals that the compound is an excellent intumescent fire retardant. __________ Translated from Acta Chimica Sinica, 2007, 65(18): 2034–2038 [译自: 化学学报]     

Polyfunctional fluoroalkyl-containing carbonyl compounds in the synthesis of heterocycles

Efficient procedures for the regioselective synthesis of fluoroalkyl-containing threefive-, six-, and seven-membered heterocycles as well as of related fused compounds, namely, α,β-epoxyketones, α,β-aziridinylketones, pyrazoles, pyrazolines, isoxazolines, 1,2-dithiolenes, amino- and mercaptopyrimidines, Δ^3,5-2-thioxo-1,3,2-thiazaphosphorines, Δ^3,5-2-thioxo-1,3,2-oxazaphosphorines, 2,3-dihydro-1,4-diazepines, azirino[1,2-a]quinoxalines, benzo[b]-and naphtho[2,3-b]-1,4-diazepines, and triazolopyridazines, which have been developed by the authors and coworkers, are summarized. The α- and β-functionalized fluoroalkylcontaining carbonyl compounds (β-diketones, β-ketoesters, their salts, regioisomeric β-aminovinyl ketones, β-aminovinylthiones, β-hydroxyketones, α,β-enones, and their halogen derivatives) were used as synthons in the processes of formation of the above-mentioned heterocycles. Dedicated to the memory of Academician I. Ya. Postovskii on his 100th birthday. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1279–1286, July, 1998.     

Triterpene glycosides ofHedera canariensis IV. Structures of glycosides L-F3, L-G0, and L-Gla from the leaves of Algerian ivy

Three minor partially acetylated glycosides have been isolated from the leaves of Algerian ivy, Hedera canariensis Willd. (Araliaceae) — the previously known {3-O-[-L-rhamnopyranosyl-(12)-O--L-arabinopyranoside] 28-O-[-L-rhamnopyranosyl-(14)-O-(6-acetyl--D-glucopyranosyl)-(16)-O--D-glucopyranoside}s of oleanolic acid and of hederagenin (ciwujianoside C₄ and kizuta saponin K₁₁) and the new 3-O-[-L-rhamnopyranosyl-(12)--O-L-arabinopyranoside] 28-O-[-L-rhamnopyranosyl-(14)-O-(6-O-acetyl--D-glucopyranosyl)-(16)-O--D-glucopyranoside of echinocystic acid (glycoside L-G₀). The structures of the glycosides isolated have been established on the basis of chemical transformations and¹H and¹³C NMR spectroscopy.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 81–86, January–February, 1999.