Intramolecular cycloadditions of keteniminium salts. A practical asymmetric synthesis of prostaglandins.

The intramolecular [2 + 2] cycloaddition of keteniminium salt 5 derived from (2S, 5S)-dimethylpyirolidine is the key step of a short synthetic route toward prostaglandins.     

2-Polyfluoroalkylchromones. 6. Synthesis of substituted 2-morpholino-2-trifluoromethylchroman-4-ones

Morpholine adds smoothly at the double bond of substituted 5- and 8-nitro-2-trifluoromethylchromones to form the corresponding 2-morpholino-2-trifluoromethylchroman-4-ones. 6-Methoxy-5-nitro-2-trifluoromethylchromone adds also benzylamine, whereas 7-methoxy-8-nitro-2-trifluoromethylchromone undergoes ring opening under the action of benzylamine to give 3-benzylamino-4,4,4-trifluoro-1-(2-hydroxy-4-methoxy-3-nitrophenyl)but-2-en-1-one.     

Vibrational studies of biomolecules. I. 2-Thiouracil

IR, far-IR and Raman spectra of 2-thiouracil are reported and interpreted. All the thirty normal modes could be assigned. The Raman spectrum and the vibrational assignments for all the thirty modes are reported for the first time. The ring breathing and Kekule stretching modes for 2-thiouracil are observed to have lower magnitudes when compared to those for uracil which could be due to the mass effect of the sulphur atom in place of the oxygen atom.     

超氧阴离子O-.2

介绍了超氧离子O2^-的产生、检测、化学性质、反应动力学、生物学研究、应用等方面的研究进展。     

Saturated Nitrogen-containing Heterocycles. 20. Catalytic Reduction of N-Hydroxyethylpyridinium and Quinolinium Salts

Previously unknown N-(2-hydroxyethyl)perhydroquinolines and N-(2-hydroxyethyl)piperidines were synthesized by catalytic reduction of N-(2-hydroxyethyl)tetrahydroquinolinium and N-(2-hydroxyethyl)tetrahydropyridinium tetrafluoroborates. A scheme for the formation of the hydrogenation products is presented.     

TLC of substituted pyridines. XII. Hydroxy derivatives

Investigations were made to determine the TLC properties of monosubstituted pyridines. The primary aim was to identify and quantitatively

2. R_f Values of Monohydroxypyridines and other Monosubstituted Pyridines (Monoamines and Monocarboxylic Acids) in Systems I and II

determine the monohydroxypyridines formed during in vitro chemical and enzymatic hydroxylation experiments.TLC studies were carried out not only on the monosubstituted pyridines, but also on 2,3-di-OH-pyridine and 3-OH-pyridine-N-oxide.The UV absorption spectra of pyridine and its substituted derivatives were recorded at a concentration of 10⁻³ M in ethanol, and were compared.The best TLC detection of these derivatives was elaborated too.     

Synthese von benzanellierten Carbacephamen, 1. Mitt.

Summary The direct intramolecular acylation and alkylation of the phenylsulfonylmethyl-group in the -lactames5a and7 are not successful. The postulated intermediate8 of the acylating reaction could be quenched with trimethylchlorosilane as the stable silylketale10. Desulfonation and desilylation of10 leads to the title compound12. The reaction of7 with base does not result in a carbacephame. Instead, the benzo[b]-azepinones15c,d have been obtained.

     

Syntheses and Olfactory Characters of Some Endo-α-Substituted-Bicyclo[2. 2. 2]-Octenyl (or Octanyl) Methanols

Sixteen title compounds were synthesized, twelve of which are new ones. Their structures were determined by 1H NMR, IR and MS, the refractive indices or melting points were measured. Odors of all the title compounds were evaluated and the structure-odor relationship was briefly discussed.     

4-Hydroxy-2-quinolones. 84. Synthesis of 5-R-5H-5,7a,12-Triazabenzo[a]anthracene-6,7-diones

2-Aminopyridines react under thermolysis conditions with ethyl 1-R-4-chloro-2-oxoquinoline-3-carboxylates exclusively in the imino form to give the corresponding 5-R-5H-5,7a,12-triazabenzo[a]anthracene-6,7-diones and 4-(pyridyl-2-amino)-1-R-quinolin-2-ones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 1060–1070, July, 2005.     

Recyclization of 2-iminocoumarins using nucleophilic reagents. 6. Reaction of 2-iminocoumarin-3-carboxamides with 2-aminobenzophenones

It has been shown that the reaction of 2-iminocoumarin-3-carboxamides with substituted 2-aminobenzophenones occurs in accordance with recyclization mechanism to form substituted 3-(4-phenylquinazolin-2-yl)coumarins. The structure of the compounds obtained was confirmed by spectroscopic data and by X-ray analysis.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1533–1542, October, 2004.     

LnHal2Hn — Neue Phasen in den ternären Systemen Ln/Hal/H. II.: Präparation

LnHal₂H_n— New Phases in the Ternary System Ln/Hal/H. II.: Preparation The hydride dihalides, LnHal₂(H,D)_n, have been prepared from LnHal₂ or from mixtures of LnHal₃ and LnH_n in welded tantalum ampoules under defined hydrogen pressures. Under 1 atm hydrogen CeBr₂H_0.87 (at 770°C), CeI₂H_0.90, CeI₂D_0.96 and GdI₂H_0.97 (at 800°C respectively) are formed as dark blue transparent platelets with a weak metallic luster. The compounds could be hydrogenated at 550°C to the colourless compounds LnHal₂H_1.00. From the equilibrium pressure isotherm (at 800°C) the lowest possible H-content of CeI₂H_n is determined to be n = 0.33 at a H₂-pressure of 0.25 mbar. The continuous variation of the H-content is characterized by a, likewise, continuous alteration of the lattice constants from a = 4.209(1) Å to 4.1697(8) Å and c = 15.218(6) Å to 15.440(2) Å for n = 0.33 to 1.00. Neither CeCl₂ nor CeCl₂H_n could be prepared. According to our investigations, the phase described as LaBr₂ can not be prepared as a binary compound. Attempts to prepare it from LaBr₂H_0.90 were unsuccessful. In contrast, GdI₂ can be prepared hydrogen free and has the heavy-atom structure of GdI₂H_n.     

Interaction of 2-Aminoindoles with Tetracyanoethylene. 1. 2-Amino-3,4-dicyano-α-carbolines and Related Compounds

2-Aminoindoles are subject to attack by tetracyanoethylene at position 3 with, when possible, subsequent ring closure.     

Heterocycles with a Bridging Nitrogen Atom. 17. Unexpected Formation of Indolizine during the Preparation of (2-Thioxopyridin-1-yl) Acetate

Ethyl 2-hydroxy-1-(2-thioxopyridin-1(2H)-yl)indolizin-3-carboxylate was formed along with ethyl (2-thioxopyridin-1(2H)-acetate from the reaction of 2-bromo-1-(ethoxycarbonylmethyl)pyridinium bromide with sodium sulfide. The structures of all compounds were confirmed by X-ray crystallography. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, 1250–1255, August, 2005.     

2-Polyfluoroalkylchromones. 7. Reactions of 6-substituted 2-tetra- and 2-pentafluoroethylchromones with 2-aminoethanol

The reactions of 2-aminoethanol with 6-methyl-2-tetra- and 6-methyl-2-pentafluoroethylchromones involve the carbonyl group to give imines; the reactions with 6-nitro-2-tetra- and 6-nitro-2-pentafluoroethylchromones involve the C(2) atom, resulting in the pyrone ring opening. This also occurs in the reactions of 2-(1,1,2,2-tetrafluoroethyl)chromone with ammonia and benzylamine.     

Interaction of 2-Aminoindoles with Tetracyanoethylene. 2. 3-Dicyano-methylene-2-iminoindolines

3-Dicyanomethylene-2-iminoindolines are obtained on interacting 2-aminoindoles with tetracyanoethylene in acidic medium. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1515–1520, October, 2005.     

肠道病毒71型外壳蛋白VP2在Pichia.pastoris酵母中的表达

利用逆转录聚合酶链式反应(RT-PCR)的方法,克隆肠道病毒71型(Enterovirus 71,EV71)SHZH03株外壳蛋白VP2基因,构建酵母分泌型表达质粒pPIC9K/VP2,经序列测定证实α-factor信号肽和VP2的序列和阅读框正确后,用SacI酶切使之线性化,电转化法将目的基因整合到宿主菌GS115基因组上;经转化子表型筛选和PCR分析鉴定后,甲醇诱导筛选到高效表达VP2蛋白的工程菌株.用饱和硫酸铵法对重组蛋白VP2进行了较好的纯化.Western Blot分析表明,重组蛋白VP2具有较好的反应原性,从而为发展EV71快速、高效、廉价诊断试剂奠定了基础.