SOLID PHASE SYNTHESIS OF ISOXAZOLINES

The solid-phase synthesis of isoxazolines on 2-polystyrylsulfonamidoethanol resin isreported. 2-Polystyrylsuifonamidoethanol resin 1 was reacted with acryloyl chloride to afford2-polystyrylsulfonylamidoethyl acrylate resin 2, which was further reacted with brominatedaldoximes by [3+2] cycioaddition to give isoxazoline resin 4. Resin 4 was treated with aqueous 6mol/L HCI solution to obtain isoxazolines in good yield and purity.     

Synthesis of 2-[β-(5′-halogenofur-2′-yl)vikyl]benzimidazoles

2-[-(5-halogenofur-2-yl)vinyl]benzimidazoles (I) have been synthesized by the condensation of o-phenylenediamine with 5-halogeno-fur-2-ylacroleins or of 2-methylbenzimidazole with 5-halogenofurfurals. The methiodides of the 1-methyl-substituted derivatives ofI readily react with secondary amines (piperidine, dimethylamine)giving methiodides of 2-[-(5-dialkylaminofur-2-yl)vinyl]-1-methylbenzimidazoles.     

Catalytic synthesis of diazines from 1,3-diaminopropane and 3-amino-1-propanol

The transformations of 1,3-diaminopropane and 3-amino-1-propanol under pulse conditions over tungsten trioxide in an inert atmosphere at 300–500 °C were investigated. The transformation of 1,3-diaminopropane leads to the formation of saturated pyrimidine bases; the maximum selectivity of the formation of hexahydropyrimidine bases at 300 °C is 60%, while the selectivity of the formation of tetrahydropyrimidine bases is 20% (400 °C). In the case of 3-amino-1-propanol the overall yield of heterocyclic bases was less than 5%, and piperazine and pyrazine derivatives were observed as the cyclic products; the formation of pyrimidine bases was not observed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 967–973, July, 1982.     

On the theory of “true” three particle scattering

The Hulthen, Kohn and Schwinger-type variational principles for the phase of true three particle scattering is formulated using the method of the hyperspherical basis. The optical theorem for such processes is proved.     

Endurance limit of polyethylene during cyclic loading under conditions of a plane stressed state

Conclusions The effect of the asymmetry of the loading cycle on the fatigue strength of HDPE subjected to biaxial tension has been studied. An increase in the acuteness of the cycle leads to an increase in the durability of the material. Under conditions of cyclic loading, the material became embrittled as the duration of the experiment was extended. The effect of various different ratios between the principal stresses on the fatigue strength of HDPE has been investigated. It has been shown that the form of the isochronous boundary curves depends on the duration of the experiment. It was established that the mechanism of HDPE fracture changes depended on the duration of the loading. The accumulation of defects, when an experiment was of average or longer duration, built up at a greater rate than would have been predicted by a linear rule for summation.M. I. Kalinin Leningrad Polytechnic Institute. The "Plastpolimer" Okhtinsk Scientific Manufacturing Association, Leningrad. Translated from Mekhanika Polimerov, No. 1, pp. 35–40, January–February, 1977.     

Effect of temperature — Time factors on the yield point of crystalline polymers in the flat stressed state (high-density polyethylene)

Conclusions 1. Experiments have been performed on biaxial stretching of HDPE over a wide range in ratios of the principal stress components, strain rates, and temperature. The character of change in the limiting characteristics of HDPE are different in different temperature regions.2. The limiting resistance of HDPE in the flat stressed state for T=const and v_i=const is described satisfactorily by the Malmeister and Gol'denblat-Kopnov criteria.3. Prediction of the limiting resistance of HDPE should be carried out within limited temperature ranges, in which similarity of strain diagrams, a similar character of structural changes in the material (accumulation of damage), and identical character of change in its limiting characteristics are observed.Okhtinsk "Plastpolimer" Scientific and Production Union, Leningrad. Translated from Mekhanika Polimerov, No. 2, pp. 247–254, March–April, 1977,     

Raman effect of light on argon atoms

Scalar scattering of light on the 3p and 3s subshells of the argon atom (Stokes scattering) and anti-Stokes scattering on the excited 4p and 4s states of argon are examined in the Hartree-Fock approximation. The calculation is made in a velocity form and in a length form. It is shown that the value in the r form is 1.5–2 times greater than in the form.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 36–42, January, 1977.     

聚L-苏氨酸修饰电极对多巴胺和肾上腺素的电催化氧化

利用循环伏安法将L-苏氨酸聚合修饰在玻碳电极表面, 制成聚L-苏氨酸修饰电极. 实验表明, 该电极对多巴胺和肾上腺素都有较好的催化氧化效果. 运用循环伏安法详细研究了修饰电极的电化学性质. 在pH 2.5的磷酸盐缓冲溶液(PBS)中, 肾上腺素的电子传递系数为0.51, 表观反应速率常数为1.33 s-1; 在pH 7.5的PBS中, 多巴胺在电极上产生一对氧化还原峰, 多巴胺在电极上的电子传递系数为0.60, 表观反应速率常数为0.92 s-1. 该修饰电极对多巴胺和肾上腺素能够进行同时测定, 还原峰电流与多巴胺和肾上腺素浓度分别在1.0×10-6-5.0×10-4 mol·L-1和3.0×10-6-1.0×10-4 mol·L-1范围内呈现良好的线性关系.     

SiHCl3-H2气相外延生长Si单晶反应机理的理论研究

采用密度泛函理论计算方法, 在B3LYP/6-311G*水平下, 计算并得到了SiHCl3与H2反应各反应通道上各驻点的构型、振动频率和能量. 结果表明, 在气相中SiHCl3分解的通道d和SiHCl3与H2反应的通道c为竞争反应, 但其均未还原出Si原子, 只有衬底Si参与SiHCl3-H2的反应, Si原子才淀积在Si衬底上.     

α-乙酰氧基-N-亚硝基吡咯烷的解离及其致癌代谢机理的理论研究

用ab initio方法, 在MP2/6-31G**水平下讨论了α-乙酰氧基-亚硝基吡咯烷(α-Acetoxy-NPYR)在各种条件下的解离反应机理, 并对形成终致癌物B, C, D的代谢机理进行研究. 发现在OH^－和H₂O作用下的解离都遵循羟基进攻羰基机理, OH^－作用下是一个经四面体中间体阴离子的无位垒过程, H₂O作用下有相对高的活化能(165.36 kJ/mol). H₃O^＋作用下是先形成阳离子产物的S_N1过程, 并没有发现遵循两种综合的解离情形. 同时, 羟基化产物异构化为终致癌物B, C, D是一个相对容易进行的过程.