The Schmidt reaction with pyridine carboxylic acids

The Schmidt reaction in oleum is used to prepare 2, 3-and 4-aminopyridines.     

On the coordination reaction of pyridine by chloroindiumtetraphenylporphyrin and its thermodynamic properties

The axial interaction of chloroindiumtetraphenylporphyrin with pyridine is studied in a mixed binary benzene-pyridine solvent of variable composition. Thermodynamic parameters of the process are determined. It is concluded on the basis of the results that the binding of pyridine to chloroindiumtetraphenylporphyrin is a low-characteristic reaction.     

A study of the reaction of iron dichloride with the pyridine activated cyclopentadiene in anhydrous 2-propanol

A reaction was studied between iron dichloride solvate and pyridine activated cyclopentadiene in anhydrous 2-propanol. We showed that pyridine hydrochloride formed in the course of this reaction can be easily separated from the target product (ferrocene) and recycled after neutralization with sodium isopropoxide, which imparts the preparative value to the studied reaction.     

Highly selective methanol-to-olefin reaction on pyridine modified H-mordenite

The effects of the acid site in main channels of MOR zeolites on their product selectivity and deactivation in the MTO(methanol to olefin) reactions were investigated. The catalytic analysis demonstrates that the pyridine modified MOR zeolite yielded high selectivity( 65.3%) of C_2~=-C_4~=, although the conversion dropped from 100% to 54%. Furthermore, both the catalytic lifetime of MOR and the stability of yielding the lower olefins were increased from less than 30 min to more than 120 min after the modification with pyridine.1H MAS NMR on MOR and modified MOR shows that the acid sites in main channel do not benefit the productivity of lower olefins and catalysts' lifetime. It can be concluded from ex-situ ~(13)C CP MAS NMR that the deposit species during the MTO reaction depend on the pore sizes, and the formation of large alkyl aromatic species more likely occurs in the 12-ring main channels rather than the 8-ring side pocket.     

Crossed bisadducts in the reaction of pyridine with two different nitrile oxides

Bisadducts of some aromatic nitrile oxides to pyridine are described. Crossed adducts are formed by exposure of pyridine to a couple of different nitrile oxides.     

Effect of pyridine on the reaction of “spanned” zinc porphyrin with organic peroxides

The reaction of “spanned” zinc porphyrin with organic peroxides in the presence of pyridine at 298 K was studied. The kinetic characteristics of the reaction were obtained. The presence of pyridine favors the formation of the zinc chlorin complex. The nature of the nitrogen base affects the character and rate of the reactions of the zinc porphyrin with peroxide. The structures of the sterically strained metal porphyrin and of the chlorin complex formed in the reaction were optimized by PM3 calculations. As follows from the geometric structure of the macrocyclic compounds, the deformations of the macroring enhance in going from zinc porphyrin to zinc chlorin.     

Cyclization reaction of cyclopentadienone with prop-2-yn-1-ol in priority to Diels-Alder reaction

2,5-Bis(methoxycarbonyl)-3,4-diphenylcyclopentadienone (1a) reacts with prop-2-yn-1-ols (2) to give 3-methylene-2,3,3a,6a-tetrahydrocyclopenta[b]furan-4-one derivatives in the presence of trialkylamines.     

吡啶光氯化反应过渡态和反应途径的量子化学研究

用量子化学B3LYP方法在3---21G*水平上优化吡啶光氯化反应加成取代反应机理生成邻、间、对位氯代吡啶不同反应途径的过渡态并对反应热和活化能进行了计算,对邻位反应途径进行了IRC反应路解析,计算结果表明邻位反应途径过渡态的能量最低,为－704.830027a.u.,生成2－氯吡啶所需的活化能最低,为114.60kJ/mol。光氯化反应主要产物为2－氯吡啶,与实验结果一致。IRC反应路径显示在反应过程中C(2)---H(7)键的断裂和C(2)-----Cl(8)键的生成是协同但不是同步的。     

Thermodynamic characteristics of the radical cation of pyridine N-oxide and its reaction with methanol

The thermodynamic characteristics of the pyridine N-oxide radical cation were obtained and the energetics of its hydration were estimated. The electrochemically generated pyridine N-oxide radical cations are capable of cleaving an H atom from methanol, which is a component of the medium.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2438–2441, November, 1989.We would like to express our deep appreciation to A. E. Shilov for his cooperation in the research and discussion of the results of the study.     

Study of the coupling reaction of pyridine in the gas phase

The coupling reaction of pyridine in the gas phase to form bipyridyl and terpyridyl has been studied by electron ionization using an ion trap mass spectrometer. In contrast to the difficulty in carrying out electrophilic substitutions at carbon atoms in the pyridine ring under highly acidic solvent conditions, reactions in the gas phase overcame the conjugate acidification of pyridine in the solvent phase, thus decreasing the hardness of this electrophilic coupling. Through product ion mass spectra of the ion at m/z 157, we have shown that this ion was protonated bipyridyl rather than the ion/molecule adduct. A computational study of the heat of formation surface also supported the formation of polypyridyls through the electrophilic substitution of pyridine. We have confirmed the reaction through a study of pyridine-d(5) coupling in the gas phase.     

Kinetic study on the system of FeOCl and pyridine

The layer compound FeOCl absorbs pyridine molecules into its interlayer regions. The kinetics of this intercalation were investigated in the temperature region from room temperature to 130°C. The reaction products had different compositions, $\text{FeOCl(pyridine)}{}_{\mathrm{<mtext>1</mtext><mtext>4</mtext>}}$ and $\text{FeOCl(pyridine)}{}_{\mathrm{<mtext>1</mtext><mtext>3</mtext>}}$, in the temperature regions below and above 60°C, respectively. Reaction mechanisms were explained by nucleation and diffusion processes. The nucleation processes followed different rate equations in the respective temperature regions, the first-order rate law at lower temperatures, and the two-dimensional Avrami-Erofeev equation at higher temperatures. The diffusion processes were well described by two-dimensional Jander's diffusion equation. Activation energies of all processes were about 10 kcal/mole.     

Preparation of aromatic polyesters by the direct polycondensation reaction with diphenyl chlorophosphate in pyridine

The direct polycondensation reaction of diphenyl chlorophosphate (DPCP) as a new condensing agent in pyridine was used for the preparation of polyarylene esters. High-molecular-weight polymers can be prepared by reacting a pyridine solution of dicarboxylic acids and DPCP in the presence of LiCl, followed by treating with a pyridine solution of bisphenols. About an equivalent of LiCl, and 30 mol % excess of DPCP were most favorably added. Effects of the initial reaction of the acids and DPCP, and of dropwise addition of bisphenols on the polycondensation were investigated. Polycondensations of several hydroxybenzoic acids were also carried out with limited success.