Peracid oxidation of benzothiopyranthiones and benzopyranthiones

Benzothiopyran-2 and 4-thiones and benzopyran-2-thiones undergo oxidation to sulphines which on further oxidation give the carbonyl derivatives or polymeric products.

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Persäure-Oxidation von Benzothiopyranthionen und Benzopyranthionen (Kurze Mitteilung)

Zusammenfassung Benzothiopyran-2 und 4-thione und Benzopyran-2-thione werden mit Persäuren zu Sulfinen oxidiert, die ihrerseits bei weiterer Oxidation die Carbonylderivate oder polymere Produkte ergeben.

     

KCl—MgCl2—H2O—DMF四元体系25℃时的等温溶度研究

结果表明:25℃时四元体系KCl-MgCl_2-H_0-DMF共有六个结晶区:MgCl_2·6H_2O,KCl·MgC_(12)·6H_2O,MgCl_2·6H_2O·2DMF,MgCl_2·2H_2O·4DMF和MgCl_2·4DMF;有九条单变线和四个四元无变点。其中KCl的相区很大,其他则相当狭小,这个结果对利用有机溶剂进行光卤石加工,分离制取KCl具有一定价值。     

非羧酸类有机化合物及其酸性

有机化学中，除了羧酸之外，存在一些不含有羧基官能结构，但仍然可在一定条件下通过相关C-H键或O-H键的异裂解离出质子，表现出一定酸性，甚至是显著酸性的有机化合物，曾被称之为假酸或碳素酸，总结了几类典型的非羧酸类有机化合物及其酸性，包括硝基甲烷、含有α-H的醛酮类化合物、乙酰乙酸乙酯、乙酰丙酮、丙二酸二乙酯、末端炔烃、醇、酚及其衍生物，并从电子结构特征出发，简要分析了其酸性的本质和影响因素，有助于全面系统学习和认识这些有机化合物的酸性。     

Magnetocaloric Effect in Anisotropic Mixed Spin ½—1 System: Pair Approximation Method

We use the Pair Approximation method to analyze the magnetic and magnetocaloric behaviors of diluted mixed spin ${\rm S_A}$=1 and spin ${\rm S_B}$=1/2 with the anisotropic Heisenberg model, on a cubic lattice with coordination number $z$=6. Our system is described in presence of an external magnetic field; the phase diagram and thermodynamic properties related to the concentration of magnetic atom (A or B) and the single ion anisotropy are constructed and discussed. Special attention is paid to magnetocaloric properties provided by isothermal entropy change as well as the cooling capacity. These cooling power keys are plotted and discussed as a function of interaction anisotropy and magnetic component concentration of two sublattices ions A and B. Numerical results show a double peak structure in the entropy change curve and the inverse magnetocaloric effect related to the presence of the negative single-ion anisotropy.     

VIBRATION AND STABILITY OF RING-STIFFENED THIN-WALLED CYLINDRICAL SHELLS CONVEYING FLUID

Based on the Flügge shell theory,equations of motion of ring-stiffened thin-walled cylindrical shells conveying fluid are developed with the aid of the Hamilton's principle.Analysis is carried out on t...     

Solvent Effect of DMSO-d6 on 1,2-Diols in 1H NMR

There is a classic experiential rule about 1,2-diol RCR^1 （OH） CR^1 （OH） R（ R^1 = H or methyl）, that is, the proton chemical shift of the α-R^1 group at the hydroxvl group in the all-isomer, in general, aPPears in a higher field with ca.     

多模叠加态|Ψe4,Ⅲ〉q中广义电场分量的N次方H压缩

利用多模压缩态理论,详细研究了由多模偶相干态和多模虚偶相干态的线性叠加所组成的一种新型的四态叠加多模叠加态光场|Ψ_e⁴,Ⅲ〉_q中广义电场分量的等幂次N次方H压缩特性结果表明:1)在腔模总数q与压缩次数N的乘积q·N=4m(m=1,2,3,…)的条件下,态|Ψ_e⁴,Ⅲ〉_q的广义电场分量可恒处于等幂次NH最小测不准态2)在q·N=4m’+2(m’=0,1,2,…)的条件下,当态间的初始相位差(θ₁-θ₂)、各模的初始相位和 φ_j,以及各模平均光子数之总和 R_j²等分别满足一定的取值条件时,态|Ψ_e⁴,Ⅲ〉_q的广义电场分量总可呈现出周期性变化的偶数次的等幂次N次方H压缩效应.     

第Ⅰ类两态叠加多模叠加态光场的非线性高阶压缩特性研究

本文在文献20的基础上进一步提出了多模辐射场的N-Y最小测不准态、N-H最小测不准态、N-Y压缩最小测不准态以及N-H压缩最小测不准态等的定义.构造了由多模(q模)相干态|{Z_j}>_q及其相反态|{-Z_j}>_q的线性叠加所组成的第Ⅰ类两态叠加多模叠加态光场|ψ₁⁽²⁾>_q,利用文献20新近提出的有关多模辐射场的两种非线性高阶压缩的定义,首次对态|ψ₁⁽²⁾>_q的N次方Y压缩及N次方H压缩效应进行了详细研究.结果表明,1)当N为偶数时,态|ψ₁⁽²⁾>_q恒处于N-Y最小测不准态;当N为奇数时,态|ψ₁⁽²⁾>_q在一定条件下可呈现出周期性变化的、任意阶的N次方Y压缩效应.2)当q·N为偶数时,态|ψ₁⁽²⁾>_q恒处于N-H最小测不准态;当q·N为奇数时,在另外的条件下,态|ψ₁⁽²⁾>_q则可呈现出周期性变化的、任意阶的N次方H压缩效应.3)N次方Y压缩及N次方H压缩效应的压缩深度与腔模总数q、压缩参数R_j以及压缩阶数N等非线性相关,后者与上述参量的非线性关联程度要比前者的更强.     

1-H and 14-N NMR relaxation studies on solutions of Mn(ClO4)2 in acetonitrile

Proton spin-lattice and spin-spin relaxation times of acetonitrile solutions of Mn(ClO₄)₂ between 298°KT413°K have been measured over a wide frequency range (10 kHzv90 MHz). From these data and corresponding 14-N NMR line width measurements of acetonitrile at varying temperatures, it is possible to extract structural and dynamical parameters such as the number of complexed acetonitrile molecules, their mean lifetime in the first solvation sphere of the manganese ions, and the rotational diffusion constant of the [Mn(CH₃CN)₆]²⁺ complex.     

Structure of azadirachtin-I, 11 β-H epimer

The 11 -H epimer of Azadirachtin-I, isolated from the seed kernels of Azadirachta indica A. Juss (Neem), was characterized by both NMR and X-ray crystallographic techniques. NMR data reveals that the H11 proton is in -orientation and the X-ray studies confirm this observation. The compound crystallized in space group P2₁ with the cell parameters a = 11.933(2) Å, b = 7.752(5) Å, c = 17.241(9) Å, = 106.80(3). Though the structural features are similar to the 11 -H epimer of Azadirachtin-H, the orientation of the acetoxy group at C3 is different. The dihedral angle C9–C8–C14–O13, which describes the relative orientation of the modified decalin and modified furan moities of the molecule, is 23.3(8).