Effective synthesis of methyl 3β-amino-3-deoxybetulinate

A practical method for preparing methyl 3β-amino-3-dexoybetulinate that is based on column chromatographic separation of 3α- and 3β-t-butoxycarbonates and subsequent removal of the protecting group using formic acid is proposed. The structure of methyl 3β-N-(t-butoxycarbonyl)-3-deoxybetulinate was established by an x-ray structure analysis. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 488–490, September-October, 2008.     

Über die Darstellung von 3β, 16α-und 3β, 16β-Diacetoxy-5α-pregnan-20-on

Zusammenfassung Die Synthese von 3, 16-Diacetoxy-5 -pregnan-20-on (VI) aus 3-Acetoxy-5 -pregn-16-en-20-on und eine verbesserte Darstellung von 3, 16-Diacetoxy-5 -pregnan-20-on (III) aus 3-Acetoxy-pregna-5, 16-dien-20-on werden beschrieben.     

Synthesis of Betulin-3-yl-β-D-Glucopyranoside

Two concise routes toward betulin-3-yl-β-D-glucopyranoside, being different in the protection of primary alcohol of betulin, were developed. The synthesis adopted a stepwise glycosidation method employing glycosyl trichloroacetimidate as donor.     

Novel Synthesis of 2β,3β,20β-Triacetoxy-5 -pregnan-6-one

Pregnenolone (2) is used in a novel synthesis of 2,3,20-triacetoxy-6-ketosteroid (6), a key intermediate in the preparation of 20-hydroxyecdysone (1)     

Synthesis of 6-chloronicotinates of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New esters of 3β,5α,6β-trihydroxysteroids and 3β,5-dihydroxy-6-ketosteroids containing 6-chloropyridine groups characteristic of the alkaloid epibatidine were synthesized by acylation with 6-chloronicotinoylchloride. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 175-179, March-April, 2009.     

Mass spectrometric analysis of androstan-17β-ol-3-one and androstadiene-17β-ol-3-one isomers

Mass spectrometric identification and characterization of steroids using electrospray ionization and tandem mass spectrometry has advantages in drug testing and doping control analysis attributable to limitations of gas chromatography followed by electron ionization mass spectrometry. Steroids with an androstadiene-17beta-ol-3-one nucleus and double bonds located either at C-1 and C-4, C-4 and C-9, or C-4 and C-6 were used to determine characteristic fragmentation pathways. Diagnostic dissociation routes are proposed using deuterium labeling, MS3 experiments, and analyses of structurally closely related compounds. Steroids such as boldenone (androst-1,4-diene-17beta-ol-3-one) produced characteristic product ions at m/z 121, 135, and 147. Compounds with double bonds at C-4 and C-9 generated abundant product ions at m/z 145 and 147. Conjugated double bonds at C-4 and C-6 gave rise to an intense and characteristic signal at m/z 133. Stereochemical differentiation between 5alpha- and 5beta-isomers of androstan-17beta-ol-3-ones was possible because of significant differences in relative abundance of product ions generated by elimination of acetone from alpha,beta-saturated 3-keto steroids.     

Practical Preparation of Resveratrol 3-O-β-D-Glucuronide

Abstract

A practical synthesis of resveratrol 3-O-β-D-glucuronide, suitable for preparation of large quantities, was developed using selective deacetylation of resveratrol triacetate with ammonium acetate. A simplified procedure for large-scale preparation of resveratrol is also reported.     

Synthesis and X-ray crystal structure of 3-deoxy-3-fluoro-β-D-allopyranoside

The synthesis of a novel compound, 3-deoxy-3-fluoro--d-allopyranoside, is described. It involves blocking the 4- and 6-positions of allose to cause fluorination only at the 3-position. This six-step synthesis gave pure crystalline compound in a 5% overall yield. The crystal structure, determined by X-ray diffraction, confirmed the chemical formula and configuration of the product. It showed that the C-F bond isaxial, while the C-(OH) bonds areequatorial. The overall conformation of this fluoroallose is similar to that of allose (Acta Cryst.1984,C40, 1863) (with OH instead of F), but the packing in the two crystals is different in the region of C3, the site of chemical variation.     

Synthesis of 1,6-anhydro-3-bromo-3,4-dideoxy-β-d-threo-hex-3-enopyranose

A preparative method for chemo- and stereoselective reduction of 3-bromolevoglucosenone into 1,6-anhydro-3-bromo-3,4-dideoxy--D-threo-hex-3-enopyranose using Zn(BH₄)₂ was developed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2455–2457, December, 1995.     

Synthesis of new α-chloropyridine derivatives of steroidal 3β,5α,6β-triols and 3β,5-dihydroxy-6-ketones

New steroid derivatives containing 6-chloropyridine groups characteristic of the alkaloid epibatidine and neonicotinoid insecticides were synthesized by reacting 3β,5α,6β-trihydroxysteroids or 3β,5-dihydroxy-6ketosteroids with 2-chloro-5-chloromethylpyridine. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 180-182, March-April, 2009.     

5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇的合成

以5-雄烯二醇为原料,用微生物转化的方法合成了两个重要的神经甾体5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇。所用菌种总枝毛霉为我们自己筛选,并首次应用于5-雄烯-3β, 7α, 17β-三醇和5-雄烯-3β, 7β, 17β-三醇的合成中。     

Synthetic Mucin Fragments: Methyl-3-O-(2-Acetamido-2-Deoxy-4-O- and 6-O-β-D-Galactopyranosyl-β-D-Glucopyranosyl)-β-D-Galactopyranoside and Methyl 3-O-(2-Acetamido-2-Deoxy-4-O- and 3-O-Methyl-β-D-Glucopyranosyl-3-D-Galactopyranoside

Abstract

Glycosylation of methyl 3-O-(2-acetamido-3, 6-di-O-benzyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (2) with 2,3,4,6-tetra-O-acetyl-α-D-galactopyranosyl bromide (1), catalyzed by mercuric cyanide, afforded a trisaccharide derivative, which was not separated, but directly O-deacetylated to give methyl 3-O-(2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-β-D-galactopyranosyl-β-D-giucopyranosyl)-2,4,6-tri-O-benzyl-β-D-galactopyranoside (8). Hydrogenolysls of the benzyl groups of 8 then furnished the title trisaccharide (9). A similar pflyccsylation of methyl 3-O-(2-acetamido-3-O-acetyl-2-deoxy-β-D-glucopyranosyl)-2,4,6-tri-O-benzyl- β-D-galactopyranoside (obtained by acetylation of 4, followed by hydrolysis of the benzylidene acetal group) with bromide 1 gave a tribenzyl trisaccharide, which, on catalytic hydrogenolysls, furnished the isomeric trisaccharide (12). Methylation of 4 and 2 with methyl iodide-silver oxide in 1:1 dichloro-methane-N, N-dimethylformamide gave the 3-O- and 4-O-monomethyl ethers (13) and (15), respectively. Hydrogenolysis of the benzyl groups of 13 and 15 then provided the title monomethylated disaechartdes (15) and (16), respectively. The structures of trisacchacides 9 and 12, and disaccharides 14 and 16 were all established by ¹³C MMR spectroscopy.     

Isolation and Crystal Structure of Stigmast-4-ene-3β,6β-diol

The title compound (C29H50O2, Mr = 430.69) was isolated from the algae Halimeda xishaensis collected from the South China Sea. Its crystal structure was determined by single-crystal X-ray diffraction for the first time. The crystal belongs to orthorhombic, space group P212121 with a = 8.1560(13), b = 10.7861 (18), c = 29.973(5) A, V = 2636.8(8)A3, Z = 4, Dc = 1.085 g/cm3, F(000)= 960, μ(Mo-Ka) = 4.533 mm-1, λ = 0.71073 A, S = 1.061, (△ρ)max= 0.382 and (△ρ)min= -0.244e/A3. The structure was refined to R = 0.0561 and wR = O. 1553 for 2711 observed reflections with I ＞ 2σ(I). X-ray diffraction analysis reveals that the title compound has two β-OH groups, and the side chain is saturated. There exist two intermolecular hydrogen bonds between three molecules.     

Phosphorylation and Amine-induced Dephosphorylation of 4-Chlorocoumarin-3-carboxaldehyde and 4-Chloro-3-(β,β-dicyanoethenylidene)coumarin

4-Chlorocoumarin-3-carboxaldehyde (1) and 4-chloro-3-( g , g -dicyanoethenylidene)coumarin (2) produce their respective 1:1 phosphonate adducts (5a-c) and (6a-c) upon reaction with the appropriate dialkylphosphonates (3a-c). Compounds 5 undergo dechlorination and dephosphorylation upon reaction with certain primary aliphatic amines to yield 9 (or 10 ) according to the nature of the amine used. Compounds 1 and 2 undergo dechlorination through reaction with hexamethyl-phosphorustriamide 4 to give the respective 4-dimethylamino-derivatives ( 11a and 11b ). Structural reasonings for the new compounds are based on compatible analytical and spectroscopic measurements. The mechanism for formation of compounds 11 also is discussed.     

Functionalization of the 3β-methyl group of penicillin

A number of penicillins functlonalized at the 3β-methyl position have been syntheslsed. The progenitor of these compounds Is the 3β-hydroxymethyl penicillin 1.     

β-Mo_2C和Ni_3Mo_3N/β-Mo_2C的制备及其甲烷化反应性能研究

通过焙烧钼酸铵和六次甲基四胺(HMT)生成的络合物,制备β-Mo_2C。在此基础上加入Ni助剂制备了Ni_3Mo_3N/β-Mo_2C双金属碳化物催化剂。采用XRD、SEM、HRTEM、低温氮吸附、元素分析等方法对催化剂进行了表征,考察了其合成气甲烷化反应性能。结果表明,β-Mo_2C有较高的CO转化率,但CO转化率和CH_4选择性分别从第10h的75.93%和36.79%降低到了第100h的67.41%和33.54%。因此,β-Mo_2C活性不够稳定且CH_4选择性较低。而Ni助剂的加入显著提高了催化剂的甲烷化活性及稳定性,使CO转化率和CH_4选择性分别从第10h的83.15%和46.64%升高到了第100h的92.51%和57.23%。这是因为Ni助剂的加入有助于生成Ni_3Mo_3N,新生成的Ni_3Mo_3N有利于甲烷化反应。     

表面活性剂AEO-3对β沸石合成的促进作用

在常规β沸石的水热合成体系中加入非离子型表面活性剂脂肪醇聚氧乙烯醚(AEO-3),按照n_(Al_2O_3)∶n_(SiO_2)∶n_(Na_2O)∶nTEAOH∶n_(H_2O)∶n_(AEO-3)∶n_(C_2H_5OH)=(0.28～1)∶40∶1.55∶10∶640∶(0.45～7.69)∶11.37的配料比,考察其作为助剂对β沸石合成的影响。实验发现,与常规合成体系相比,AEO-3的加入可促进硅铝酸盐溶胶的生成并增加了其均匀化程度,同时增加了产品收率。所合成样品的X射线衍射、N_2和Ar吸附-脱附、扫描电镜、固体核磁和正癸烷吸附的表征结果表明,表面活性剂AEO-3的加入使β沸石的纳米晶粒更加完整与均匀,提高了结晶度和微孔体积,并使得收率提高。所合成的β沸石的骨架硅铝比提高,酸强度增加。另外,AEO-3的加入提高了β沸石结构中的手性多形体A的比例。     

Circular Dichroism Spectra of Stigmastane 3β-Benzoyloxy-6-ketosteroids

CD spectra of stigmastane derivatives containing a 3-benzoyloxy group and a saturated or conjugated 6-ketone were studied. Application of known empirical rules to functional groups enabled the mutual influence on the optical activity of their electronic transitions in the compounds to be evaluated. It has been demonstrated that CD spectra can be used to prove the structures of these steroids.