Umsetzung von 1,5-Dimethyl-2,3,3,4-tetrachlor-1,5,2,4-diazadiphosphorinan-6-on mit Anilinderivaten,Heptamethyldisilazan und tert.-Butylamin: Oxidative Addition von Tetrachlor-o-benzochinon an einige P(III)-haltige Produkte

The reaction of the title compound 1 with the p-R-aniline derivatives (R═H, F, OCH₃, NO₂, and NH₂) led to the formation of the aza-2σ³,4σ³-diphosphetidines 2a– 2e, whereas 2-trimethylsiloxyaniline furnished the azadiphosphetidine 2f. The reaction of the sterically crowded 2,6-dimethylaniline with 1 furnished the disubstituted derivative 3. The tricyclic compound 5 was formed during the reaction of 1,2-phenylenediamine with 1. Heptamethyldisilazane formed the aza-2σ ³ ,4σ ³ -diphosphetidine 6 on reaction with 1. The bulkier tert.-butylamine formed with 1 a mixture of the aza-2,4-diphosphetidine 7a and the disubstituted derivative 7b, which could not be separated. The reaction of 2b and 6 with tetrachloro-o-benzoquinone resulted in the formation of the bis-spirophosphoranes 8 and 9b, respectively. The formation of the monospirophosphorane 9a was observed in the ³¹P NMR spectrum. The characterization of compounds is based in particular on NMR investigations (¹H, ¹³C, ³¹P). 2a was characterized by a single-crystal X-ray structure analysis. The dimethylurea fragment is planar; the four-membered ring is folded about the P···P vector by 38.7°.     

气相中CrO2+活化甲烷C—H键的理论研究

用密度泛函UB3LYP/6-311＋＋G**方法计算研究了气相中CrO₂⁺ (²A₁/⁴A")活化甲烷C—H键的微观机理, 找到了四条反应通道. 对其中涉及的两态反应(TSR)进行了分析, 并对影响反应机理和反应速率的势能面交叉现象(potential energy surfaces crossing)进行了详细讨论, 进而运用Hammond假设和Yoshizawa等的内禀坐标单点垂直激发计算的方法找出了一系列势能面交叉点[crossing points (CPs)], 并作了相应的讨论. 进一步用碎片分子轨道理论[fragment molecular orbital (FMO)]对TS1中的轨道相互作用进行了分析, 解释了CrO₂⁺活化甲烷C—H键的机理.     

Facile synthesis of some new functionalized 2-selenoxopyrimidines

Abstract

Some new functionalized 2-selenoxodihydropyrimidines 1–6 were synthesized in good yields via a simple one-pot reaction. The simple method depended on the reaction of selenourea with some nitrile active methylene compounds under basic-catalyzed conditions. Also, treatment of selenourea with each of malononitrile and ethyl cyanoacetate in the presence of benzaldehyde under the same basic reaction conditions afforded the 2-selenoxopyrimidine-5-carbonitriles 7 and 8, respectively. Furthermore, selenourea reacted with benzaldehyde and different β-dicarbonyl compounds under Biginelli reaction conditions to afford the 2-selenoxo-1,2,3,4-tetrahydropyrimidine-5-carboxylates 10, 11 and 13. Using acetylacetone as a substrate in Biginelli reaction yielded the unexpected 5-benzylidene-4,6-dimethyl-pyrimidine-2(5H)-selenone (14). The structures of the synthesized compounds were established on the basis of elemental analysis, IR, ¹H- and ¹³C-NMR and mass spectral data.     

Studies on the Thermodynamic and Kinetic Properties of the Reactions of Ti+ with Sulfur Transfer Reagent SCO Along the C═S Bond Activation Branch at 200–1200K

Theoretical studies on the thermodynamic and kinetic properties of the reactions of Ti⁺ with sulfur transfer reagent SCO via the C═S bond activation pathway have been carried on using DFT/B3LYP method, general statistical thermodynamics, and Eyring transition state theory with Wigner correction. The relevant reactions include reaction 1 ⁴ Ti⁺+¹SCO → ⁴ IM ₁ → ⁴ TS ₁ → ⁴ IM ₂ → ⁴ TiS⁺+ ¹ CO, and reaction 2 ⁴Ti⁺+¹SCO →⁴IM₁→ CP →²IM₂→²TiS⁺+¹CO in which the spin multiplicity changes from the quartet state to the doublet state in the crossing region. It is concluded that the increase of the temperature is favored to the reaction 1 process, since the equilibrium constants (K) rises from 0.566 × 10[P]-9 at 200 K to 0.109 × 10⁰ at 1200 K, and the reaction rate constant (k) from 0.222 × 10⁰ s[P]-1 at 200 K to 0.540 × 10 ¹¹ s[P]-1 at 1200 K. Moreover, reaction 1 is endothermic, and non-spontaneous in the way the entropy increases, while reaction 2 is exothermic and spontaneous in the way their entropy decreases. The reaction path 2 is the energetically favorable channel, and its thermodynamic data change not largely with the rise of temperature.     

Reactivite Des α -Phosphonylketones Dans la Reaction de Gewald: Synthese de Nouveaux Derives de L′aminophosphonothiophene

The reaction of α -phosphonylketones 1 with active methylenenitriles 2 leads to phosphonoalkylidenes 3 . The reaction of compounds 3 with sulfur under basic conditions leads to the new 2-amino-4-phosphonothiophenes 4 . The structure of all obtained products was confirmed by NMR (¹H, ³¹P, ¹³C) and IR spectroscopy, and in some cases by mass spectrometry.     

Thermodynamic and kinetic properties of scandium (I) ion reacting with SCO in gas phase

Theoretical studies on the thermodynamic and kinetic properties of the reactions of scandium (I) ion with the sulfur-transfer reagent SCO via the C-O bond activation pathway have been carried out over the temperature range of 200-1200 K using the DFT/B3LYP method, general statistical thermodynamics, and Eyring transition state theory with Wigner correction. The relevant reactions include reaction 1 ¹Sc⁺ + SCO → ¹IM1 → ¹TS1 → ¹IM2 (Step 1) → ¹TS2 → ¹IM3 → ¹ScO⁺ + ¹CS (Step 2), and reaction 2 ³Sc⁺ + SCO → ³IM1 → CP → ¹IM2 → ¹TS2 → ¹IM3 → ¹ScO⁺ +¹CS in which the spin multiplicity changes from the triplet state to the singlet state in the crossing region. It was concluded that the order of the equilibrium constants (K) and the reaction rate constants (k) are consistent with that of their corresponding exoergic energies, ΔE, and reaction barriers, respectively. Step 2 of reaction 1 is both thermodynamically and kinetically favored over the whole temperature range. Moreover, both Reaction 1 and reaction 2 are exothermic and spontaneous processes in which their entropy increases, and the magnitudes of their thermodynamic values all decrease with increasing temperature.      

Synthesis and spectroscopic studies of new organotin(IV) complexes with tridentate N- and O-donor Schiff bases

The Schiff bases H₂L¹ and H₂L² have been prepared by the reaction of 2-amino-4-chlorophenol with pyrrole-2-carbaldehyde and 2-hydroxy-1-naphtaldehyde, respectively, and HL³ from reaction of 2-(aminomethyl)pyridine with 2-hydroxy-1-naphtaldehyde. Organotin complexes [SnPh₂(L¹)] (1), [SnPh₂(L²)] (2), [SnMe₂(L²)] (3) and [SnPhCl₂(L³)] (4) were synthesized from reaction of SnPh₂Cl₂ and SnMe₂Cl₂ with these Schiff bases. The synthesized complexes have been investigated by elemental analysis and FT-IR, ¹H NMR and ¹¹⁹Sn NMR spectroscopy. In complexes the Schiff bases are completely deprotonated and coordinated to tin as tridentate ligands via phenolic oxygen, pyrrolic, and imine nitrogens in 1, two phenolic oxygens and imine nitrogen in 2 and 3, and phenolic oxygen, imine and pyridine nitrogens in 4. The coordination number of tin in 1, 2, and 3 is five and in 4 is six.     

Synthesis and Characterization of Bimetallic Nickel and Cobalt Carbonyl Complexes Containing Stannyl Groups

The bimetallic NiSn₂ complex Ni(SnBu₃^t)₂(CO)_3, 1, was obtained from the reaction of Ni(COD)₂ and Bu₃^tSnH and CO. The reaction of Co₂(CO)₈ and Bu₃^tSnH afforded the bimetallic Co–Sn complex Co(SnBu₃^t)(CO)₄, 3. Compound 3 was also obtained from the reaction of Co₄(CO)₁₂ and Bu₃^tSnH but in a lower yield. Both compounds 1 and 3 were characterized by single crystal X-ray diffraction, and possess trigonal bipyramidal geometries around the transition metal centre with two and one stannyl ligands, respectively.     

含能富勒烯吡咯烷衍生物的合成及工艺研究

利用Prato反应合成分离出了新型含硝基富勒烯吡咯烷衍生物1, 并对其工艺条件进行了研究, 探讨了反应物计量比、温度及时间对产物1产率的影响, 得到了合成产物1的最佳工艺条件: C₆₀, 间硝基苯甲醛和N-甲基甘氨酸的物质的量比为1∶1∶2, 温度为100 ℃, 反应时间为16 h, 此时产物1产率达到94.8%(以消耗的C₆₀计). 同时用UV-Vis, FT-IR, ¹H NMR, ¹³C NMR and MS spectra等光谱手段确定了产物1的分子结构.     

Sulfite Determination with Gold Electrode Promoted by bis(4-Pyridyl)disulphide/cytochrome C

Abstract

A biosensor was developed using oxidized cytochrome C - sulfite reaction by following the electrochemical reaction between reduced cytochrome C and gold electrode. The change in the current at the fixed potential equal to anodic peak potential of cytochrome C was proportional to sulfite concentration in the range of 0.4×10^?4 to 4.0×10^?4 M.     

A Superacid-catalyzed Synthesis of Fluorescent Covalent Triazine Based Framework Containing Perylene Tetraanhydride Bisimide for Sensing to O-nitrophenol with Ultrahigh Sensitivity

Abstract

A mesoporous covalent triazine framework, PCPDI, was synthesized via an aromatic nitrile trimerization reaction of N,N′-di(4-cyanphenyl)- 3,4,9,10-tetracarboxydiimide (CPDI) by CF₃SO₃H catalyzed at 40?°C and this method avoids the use of noble metal catalyzers or high temperature reaction. PCPDI exhibits high thermal stability and strong fluorescence. The PCPDI shows ultrahigh sensitivity to tracing o-nitrophenol in chloroform with K_SV constant of 1.74?×?10⁵ L mol^?1 and detection limit (LOD) of 1.72?×?10^?11?mol L^?1.     

DIFFÉRENCE DE COMPORTEMENT ENTRE LES RÉACTIFS ELECTROPHILES DIÉTHYLTRICHLOROMÉTHYLPHOS- PHONATE ET TÉTRACHLORURE DE CARBONE OPPOSÉS AU TRIÉTHYLPHOSPHITE

Abstract

The reaction of triethylphosphite 1 with diethyltrichloromethylphosphonate 2b in the absence of solvents and catalysts yields mainly diethyl(1,1-dichloropropyl)phosphonate 4 and diethyldichloromethylphosphonate 7. These main products are accompanied by a variety of by-products which differ considerably from those obtained in the reaction between triethyl phosphite and CCl₄. Both reactions would begin by a halophilic substitution of triethylphosphite on the positive halogen. For diethyltrichloromethylphosphonate 2b the formed carbanion would then attack preferentially the carbon β to P⁺ and the hydrogen γ to P⁺ on heterophosphonium cation. In contrast, the less sterically hindered trichloromethyl carbanion formed by the halophilic attack of triethylphosphite on carbon tetrachloride would rather attack mainly the positive P⁺ of this cation. The tetraethyl(dichloromethylene)bisphosphonate 8 previously reported by Kukhar and Sagina to be the main product formed in the thermal reaction between triethylphosphite and diethyltrichloromethylphosphonate was not found under our conditions. We observed its formation only under photochemical irradiation.     

A Convenient Synthesis of N-Functionalized Perfluoroalkanesulfonamides

This article describes the synthesis of new N-functionalized perfluoroalkanesulfonamides (5) with two sulfonamides functionalities. Perfluoroalkanesulfonyl fluoride underwent a reaction with 2-chloroethylamine hydrochloride or 3-bromopropylamine hydrobromide to give N-(2-chloroethyl or 3-bromopropyl) perfluoroalkanesulfonamides (1). Reaction of (1) with potassium thiocyanate gave N-(2-thiocyanatoethyl or 3-thiocyanatopropyl) perfluoroalkanesulfonamides (3). The sulfonyl chloride derivatives (4) were prepared by reaction of 3 with sulfuryl chloride. In the last step, 4 reacted with ammonia to give the bis sulfonamides derivatives (5). The structures of all new compounds prepared were determined by ¹H, ¹⁹F, and ¹³C NMR spectroscopies and by HR-MS.     

Decomposition of dioxetane induced by electron transfer from a photoexcited lanthanide ion

The photodecomposition of adamantylideneadamantane-1,2-dioxetane (1) in the presence of Ce³⁺ is discovered. Electron transfer plays a dominant role in the reaction mechanism. The photoirradiation of solutions of1 and CeCl₃ within the absorption region of the latter leads to the decomposition of1 with the initial quantum yield φ=0.29±0.03. The reaction is caused by the dynamic extinction of the photoluminescence of^*Ce³⁺ ions by dioxetane1. Adamantanone is the main product of the photocatalytic reaction. However, side products of the interaction of the intermediate 1,4-dioxyradical anion with the solvent are also formed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1824–1826, October, 1993.     

Nature of sulfur centered radicals formed during pulse radiolysis of 2-mercaptopyridine in aqueous solutions

Spectral, redox and kinetic properties of the transient species formed by the reaction of 2- mercaptopyridine (2-MPy) with oxidants such as OH, Br¯₂ ^. ; N ^. ₃ and Cl¯₂ ^. radicals and reductants such as e¯_aq, H-atoms and (CH₃)₂ ^. COH radicals have been studied by pulse radiolysis technique. Reaction of one-electron oxidants with 2-MPy at pH 11.5 led to the formation of 2-pyridyl thiyl radical. The reduction potential for the couple C₅H₄NS ^. /C₅H₄NS¯ was estimated to be 0.84 V vs NHE from the equilibrium studies with I¯₂ ^. /2I¯ couple. At pH 6.8, the reaction of N ^. ₃ radical with 2-MPy gave a cation radical derived from 2-MPy. At pH 6.8 and 11.5, OH radicals react with 2-MPy by addition pathway. Reaction of e¯_aq with 2-MPy was found to give a reducing radical capable of transferring electron to methyl viologen. At acidic pH, the reaction of (CH₃)₂ ^. COH radicals and H-atoms with 2-MPy gave transient species identical to those produced by the reaction of oxidising radicals, namely, OH radicals, Cl¯₂ ^. and Br¯₂ ^. radicals.     

Construction of Extended and Polymeric 1,3-Dithiolane and Tetrathiafulvalene Derivatives using Cycloaddition of Bun 3P.CS2

Abstract

Cycloaddition of the adduct between Buⁿ ₃P and CS₂ to strained double bonds such as in norbornene gives novel zwitterionic products such as 5. This dissociates to the ylide 4 so that carrying out the reaction in the presence of an aldehyde leads to a Wittig reaction to give 2-alkylidene-1,3-dithiolanes. The compound 5 reacts with acetylenic dipolarophiles by cycloaddition accompanied by loss of Buⁿ ₃P to give dihydro-TTF derivatives. Both these reaction types also occur for norbornadiene and by using this together with dialdehydes or diacetylenes a range of new sulfur-rich extended and polymeric structures have been obtained.     

Microwave-assisted synthesis and characterization of a new metal-free and metallophthalocyanines

Dinitrile monomer (3) was synthesized by nucleophilic aromatic substitution of 4-phenoxyphenol (1) with 4-nitrophthalonitrile (2). The metal-free phthalocyanine (4) was prepared by the reaction of dinitrile monomer (3) with DMAE. Ni(II), Co(II), and Zn(II) metallophthalocyanines were prepared by the reaction of 3 with chlorides of Ni(II), Co(II), and Zn(II) in DMAE. The new compounds were characterized by IR, ¹H- and ¹³C-NMR, UV-Vis, elemental analysis, and MS specral data.     

ACTION DES CYANOARYLIDENES ACTIVES SUR LES β -CETO- δ -CARBETHOXYPHOSPHONATES ET PHOSPHINEOXYDES: SYNTHESE DE 2-AMINO-6-(PHOSPHONOMETHYL)-4H-PYRANES

The reaction of β-keto-δ-carbethoxyphosphonates and phosphineoxides 1 with active cyanoarylidenes 2 in basic conditions provides a convenient access to the new 2-amino-6-(phosphonomethyl)-4H-pyranes 3. The reaction is found to be highly regioselective. The structure of all obtained products is confirmed by NMR ( ¹ H, ³¹ P, ¹³ C), IR spectroscopy, and in some cases by mass spectrometry.     

CH3S与HCS双自由基反应的密度泛函理论研究

应用量子化学从头算和密度泛函理论(DFT)对CH₃S与HCS双自由基单重态反应进行了研究. 在MPW1PW91/ 6-311G(d,p)水平上优化了反应通道上各驻点(反应物、中间体、过渡态和产物)的几何构型, 用内禀反应坐标(IRC)计算和频率分析方法对过渡态进行了验证. 在QCISD(t)/6-311＋＋G(d,p)水平上计算各物种的单点能, 并对总能量进行了零点能校正. 研究结果表明, CH₃S与HCS反应为多通道反应, 有4条可能的反应通道, 反应物首先通过S…S弱相互作用形成具有竞争反应机理的五元环硫-硫偶合中间体a和链状硫-硫偶合中间体c, 再由此经过氢迁移、离解、异构化等不同机理得到主要产物P1 (2CH₂S), 次要产物P2 (CH₃SH＋CS), P3 (CH₄＋CS₂)和P4 [CH₂(SH)CSH]. 根据势能面分析, 所有反应均为放热反应, 生成P1的反应热为－165.55 kJ•mol^－1. 通道R→a→TSa/b→b→P1为标题反应的主通道, 其速控步骤a→TSa/b→b在200～2000 K温度区间内的速率常数可以表示为k₁^CVT/SCT＝1.75×10¹⁰T^0.65exp(－907.6/T) s^－1. P3及P4的生成需要越过很高的活化能垒, 是动力学禁阻步骤, 但在反应体系中加入合适催化剂, 改变其反应机理, 有可能使生成CH₂(SH)CSH, CH₄及CS₂的反应易于进行.     

3-(4-β-D-吡喃阿洛糖苷-苯基)-4-芳基-5-芳基-1,2,4-噁二唑啉的合成及其镇静活性的研究

以豆腐果苷为原料, 与盐酸羟胺缩合反应生成4-β-D-吡喃阿洛糖苷-苯甲醛肟(2), 2与次氯酸叔丁酯发生取代反应生成4-β-D-吡喃阿洛糖苷-α-氯苯甲醛肟(3); 再将3与Schiff碱通过1,3-偶极环加成生成一系列3-(4-β-D-吡喃阿洛糖苷-苯基)-4-芳基-5-芳基-1,2,4-噁二唑啉(5a～5h). 3和 5a～5h共9个化合物均未见文献报道, 其结构经¹H NMR, IR和MS (HRMS)加以确认, 并对5a～5h进行了药理活性筛选. 结果表明, 部分化合物具有良好的镇静活性. 其中, 化合物5g (200, 100 mg•kg^－1)和5h (200, 100 mg•kg^－1)与豆腐果苷相比较具有更强的活性.