Cycloaddition in Condensed Isoindoles. 2. Method for Obtaining New Derivatives of 2-Phenylpyridine

The reaction of pyrido[2,1-a]isoindole with maleimide derivatives has been investigated. A new rearrangement has been found, the products of which are 2-[2'-(1-R-2,5-dioxopyrrolidinidene)-2'-(1-R-2,5-dioxopyrrolidinyl)methyl]phenylpyridines. A probable mechanism for the rearrangement has been proposed. The existence of atropoisomerism for the compounds obtained has been demonstrated by ¹H NMR spectra.     

Synthesis of indanones via solid-supported [2+2+2] cyclotrimerization

A new facile approach toward natural and unnatural indanones has been developed, featuring a solid-supported [2+2+2] cyclotrimerization as the key step. This strategy has been applied to the chemo- and regioselective assembly of indanone arrays and to the total synthesis of a recently isolated indanone marine natural product.     

Oxazolidines. 2. Synthesis of 2-methyloxazolidines by cyclization of vinyl ethers of 1, 2-amino alcohols

A study has been made of the catalytic activity of a number of proton acids and Lewis acids, amongst which mercury salts were particularly active, in the cyclization of N-phenylethanolamine vinyl ether to 2-methyl-3-phenyloxazolidine. A method for the preparative synthesis of 2-methyloxazolidines has been developed.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 536–538, April, 1986.     

Kinetic studies of 2-methoxyethanol and 2-ethoxyethanol by pentavalent vanadium in aqueous sulphuric acid medium

Summary The kinetics of oxidation of 2-methoxyethanol and 2ethoxyethanol by vanadium (V) in aqueous sulphuric acid medium has been studied. The order of reaction with respect to the oxidant and substrate has been found to.be unity. The energy of activation has also been calculated graphically. A probable mechanism has been proposed.     

Synthesis and properties of aroyl derivatives of 2-imidazolone and 2-benzimidazolone

A series of C-aroyl derivatives of 2-imidazolone and 2-benzimidazolone has been obtained by the reaction of the chlorides of the corresponding carboxylic acids with imidazolone and benzimidazolone in the presence of anhydrous aluminum chloride. A consideration of the IR spectra has shown that the substances synthesized have the lactam structure in the solid state.     

Ab initio vibration and ro-vibrational spectrum of the 1A1 state of He2Si2+

The low-lying ro-vibrational states for the ground electronic state (1A1) of HeSi2+ have been calculated using an ab initio variational solution of the nuclear Schr?dinger equation. A 96 point CCSD(T)/cc-pCVQZ potential energy surface (PES) has been calculated and a Ogilvie-Padé (3,6) potential energy function has been generated. This force field was embedded in the Eckart-Watson Hamiltonian from which the vibrational and ro-vibrational eigenfunctions and eigenenergies have been variationally calculated. A 70 point QCISD/aug-cc-pCVTZ discrete dipole moment surface (DMS) was calculated and a 5th order power series expansion (in terms of the two bond lengths and the included bond angle) has been generated. Absolute line intensities have been calculated and are presented for some of the most intense transitions between the vibrational ground state and the low-lying ro-vibrational states of this ion.     

Triphenylphosphine-Mediated Synthesis of Methyl 2-Aroyloxypropenoates from 2-Aroyl-2-methoxycarbonyloxiranes

A new synthesis of several 2-aroyloxypropenoic acid methyl esters 5 by the reaction of 2-aroyl-2-methoxycarbonyloxiranes 2 with triphenylphosphine in tetrahydrofuran has been described.     

A Facile Synthesis of 2-Aroylindoles by the Oxidation of 2-Arylmethylindoles Using Sarett Reagent

Abstract

A facile synthesis of 2-aroylindoles by the oxidation of 3-substituted 2-arylmethylindoles using Sarett reagent has been reported. The phenylthio group at 3-position has been cleaved by Raney nickel.     

Intermolecular interaction potentials for the Ar-C2H2, Kr-C2H2, and Xe-C2H2 weakly bound complexes: information from molecular beam scattering, pressure broadening coefficients, and rovibrational spectroscopy

Integral cross sections and pressure broadening coefficients have been measured for the acetylene-krypton complex, by molecular beam scattering and by high resolution IR spectroscopy, respectively. A new potential energy surface (PES) is proposed to describe structure and dynamical properties of this prototypical weakly bound complex. The PES has been parametrized exploiting a novel atom-bond pairwise additive scheme and has been fitted to the experimental data. A similar PES has been obtained for the acetylene-xenon system by a proper scaling of the interaction parameters of the krypton case, based on empirical considerations. These PESs together with that recently proposed by the same authors [J. Phys. Chem. 109, 8471 (2005)] for the acetylene-argon case have been employed for close coupling calculations of the pressure broadening cross sections and for a characterization of the rovibrational structure of the complexes.     

Total synthesis of deglyco-bleomycin A2

Deglyco-bleomycin A2, the aglycon of bleomycin A2, has been synthesized for the first time.     

He*(23S)/CO2与CS2反应的化学发光

亚稳态原子（或分子）的传能反应，多年来一直受到人们的重视问．Cs。是涉及大气光化学、环境污染的重要分子之一，研究CS。与He”怦S）／CO。的碰撞反应是这些领域共同感兴趣的课题．Masaharu同详细地讨论了He”怦S）／CO与CS。的传能反应·本文在流动余辉装置上，研究了He“怦S）／CO。与CS。传能反应，对实验观察到的电子激发态产物CSt（A、CS（A，a）形成机理进行了讨论．1实验实验装置如图1所示·高纯的He体积分数为99．99％）通过两个装满了分子筛的液氮冷阶进一步提纯，然后由空。。阴极放电产生亚稳态He“炉S）原子·为…     

高碘酸盐-硫脲-硫酸反应体系的非线性动力学

研究了KIO4 SC(NH2)2 H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象；在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值[KIO4]0/[SC(NH2)2]0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象.     

Selective functionalization of 2-oxoallobetulin derivatives

A new series of 2-oxoallobetulin derivatives has been synthesized by using various unique reactions. Site-specific or regio-selective functionalization of those compounds has been investigated. In all cases, the reactions only happened at C-3 position except the synthesis of lactam happened at C-1 position. The intermediates leading to the novel allobetulin derivatives have also been described.     

Rapid assembly of polycyclic substances by a multicomponent cascade (4 + 2)-(2 + 2) cycloadditions: total synthesis of the proposed structure of paesslerin A

A versatile method for stereoselective formation of multisubstituted bicyclo[4.2.0]octane framework has been developed by means of catalytic (4 + 2)-(2 + 2) cycloaddition reactions. Its application to the synthesis of a substance reported to be the cytotoxic sesquiterpene, paesslerin A, is described, and it has been made clear that a revision of the structure of natural paesslerin A is required.     

Phenanthridine synthesis via [2+2+2] cyclotrimerization reactions

A concise synthesis of phenanthridines via a microwave-assisted [2+2+2] cyclotrimerization reaction has been developed.     

Synthesis and reactions of thioamides of 5-amino-2-aryl-2H-1,2,3-triazole-4-carboxylic acid

A method has been developed for obtaining thioamides of 5-amino-2-aryl-2H-1,2,3-triazole-4-carboxylic acid. Their heterocyclization reactions with bifunctional reagents has been studied. New heterocyclic polycyclic ensembles have been synthesized containing a 1,2,3-triazole fragment, a thiazole, and a residue of the natural alkaloid cytisine.     

Spectral analysis of Mn2+, Co2+ and Ni2+: B2O3-ZnO-PbO glasses

This paper reports on the spectral properties of Mn2+, Co2+ and Ni2+ ions doped B2O3-ZnO-PbO glasses. XRD, FT-IR spectra and DSC profiles of these glasses have also been carried out, and the FT-IR profiles have shown the presence of both BO3 and BO4 units. It is interesting to notice that the FT-IR peak positions are slightly shifted towards higher energy with an increase in transition metal ion concentration change. From the measured DSC thermograms, glass transition (T(g)), crystallization (T(c)) and temperature of melting (T(m)) have been evaluated. From the UV absorption spectra of Mn2+, Co2+ and Ni2+ ions doped glasses, both direct and indirect optical band gaps have been calculated. The visible absorption spectra of Mn2+:glasses have shown a broad absorption band at 520 nm (6A1g(S) --> 4T1g(G)); with Co2+ ions one absorption band at 605 nm (4A2(4F) --> 4T1(4P)) and another at 1450 nm (4A2(4F) --> 4T1(4F)); and for Ni2+:glasses three absorption bands at 420 nm (3A2g(F) --> 3T1g(P)), 805 nm (3A2g(F) --> 1Eg(D)) and 880 nm (3A2g(F) --> 3T1g(F)) have been observed. For Mn2+:glasses, upon excitation with 262 nm, a green emission (539 nm) with a slight blue shift; and with 392 nm, a green emission (534 nm) with a slight red shift with Mn2+ ions concentration change (0.2-0.5 mol%) has been observed. This green emission has been assigned to (4T1(G) --> 6A1(S)) d-d transition of Mn2+ ions that are in tetrahedral co-ordination. For 0.5 mol% Co2+ ions doped glass, upon excitation with 580 nm, a red emission (625 nm) has been observed which originates from 2E(2G) --> 4A2(4F) transition of Co2+ ions in tetrahedral co-ordination. For Ni2+ ions doped glasses upon excitation with 420 nm, a green (577 nm) and red (670 nm) emissions are observed and are assigned to (1T2g(D) --> 3A2g(F)) and (1T2g(D) --> 3T2g(F)) d-d transitions of Ni2+ ions in octahedral co-ordination.     

An ESR study of titanium-silicalite in presence of H2O2

The interaction of H2O2 with TS-1 has been investigated by the ESR technique. A well manufactured TS-1 has been considered, where the presence of extra-structural titanium can be excluded. The two main signals observed are attributed to oxygen radical species co-ordinated on structural titanium sites, and the relevant effect of water presence in the paramagnetic complex is discussed. A comparison is performed with O2-/Ti species in TS-1 obtained by reduction/re-oxidation procedures of Ti(IV). Moreover, some possible structural configurations of the paramagnetic sites are proposed, for two of which ab initio calculation yield g(z)-values quite close to the experimental ones.     

NaRuO2 and NaxRuO2.yH2O: new oxide and oxyhydrate with two dimensional RuO2 layers

The new oxide and oxyhydrate NaRuO2 and NaxRuO2.yH2O (x = 0.22, y = 0.45) have been characterized. NaRuO2 is isostructural with alpha-NaFeO2. The symmetry is rhombohedral (R3m space group) with lattice parameters of a = 3.018(2) A and c = 16.493(3) A. The structure has been refined by the Rietveld method. The oxyhydrate NaxRuO2.yH2O has been prepared by stirring a sample of NaRuO2 in water at ambient temperature. NaxRuO2.yH2O crystallizes in the space group R3m with lattice parameters of a = 2.930(2) A and c = 21.913(5) A. The structure is related to the CuFeO2 3R polytype structure with the AABBCC sequence of the oxygen close packed layers along the c-axis. Analogies with the related cobalt phases are discussed. The susceptibilities of NaRuO2 and NaxRuO2.yH2O are small and constant in a large temperature range.     

Methylation of 2-phenylamino-1,3,4-thiadiazole. A structure debated

The true identity of the 4-methyl-5-phenylimino-δ²-1,3,4-thiadiazoline (A) has been demonstrated. The reactions, previously reported in the literature to give A have been repeated and the structure of the compounds obtained has been established.