双甲基丙烯酰氧苯基丙烷与苯乙烯共聚物的光学性能

标题共聚物的耐冲击性与丙烯酸酯均聚物相比有明显改善,但随着双烯单体含量的降低,共聚物的耐热性和表面硬度有所下降。丙烯酸酯含量为70%的共聚物的吸收紫外光能力最强(<370nm全吸收),含量为5%～10%的共聚物耐吸水性、耐酸耐碱性及耐冲击性最好。     

7-氮杂-3,6-二氧杂-二环[3.3.0]辛-2-酮类化合物合成的新方法

5-甲氧基-2-（5H）-呋喃酮与氮酸硅烷基酯通过1，3-偶极环加成反应可以为7-氮杂-4-甲氧基-3，6-二氧杂-二环[3.3.0]辛-2-酮类化合物提供新的合成途径。通过元素分析、IR、^1HNMR、^13CNMR、MS等波谱分析进行了结构表征。     

1,5-Diazabicyclo[3.1.0]hexanes and 1,6-diazabicyclo[4.1.0]heptanes: a new method for the synthesis,quantum-chemical calculations,and X-ray diffraction study

A new method was developed for the synthesis of 6-substituted 1,5-diazabicyclo[3.1.0]hexanes and 7-substituted 1,6-diazabicyclo[4.1.0]heptanes by condensation of N-monohalotrimethylene- and N-monohalotetramethylenediamines with carbonyl compounds in the presence of bases. X-ray diffraction studies and quantum-chemical B3LYP/6-31G* calculations demonstrated that the conformations of the resulting bicyclic systems are stabilized by stereoelectronic interactions. As a result, a boat conformation prevails in 1,5-diazabicyclo[3.1.0]hexanes, whereas the energies of chair, half-chair, and boat conformations of 1,6-diazabicyclo[4.1.0]heptanes are equalized.     

Efficient synthesis of 2- and 3-substituted-2,3-dihydro [1,4]dioxino[2,3-b]pyridine derivatives

A versatile new approach for the synthesis in three steps of 2-substituted-2,3-dihydro[1,4]dioxino[2,3-b]pyridines B via a Smiles rearrangement using easily available reagents is described. A study illustrating the influence of experimental conditions on the progress of the reaction is reported.     

[2+2]-Photocycloaddition von Cyclohexen an 2-Acetyl-5,5-dimethyl-1,3-cyclohexandion und 3-Acetyl-1,5,5-trimethyl-2,4-pyrrolidindion

Summary Irradiation of solutions of excess cyclohexene and 2-acetyl-5,5-dimethyl-1,3-cyclohexanedione (1), and 3-acetyl-1,5,5-trimethyl-2,4-pyrrolidinedione (4) results mainly in the formation of 1,5-diones2 and5. These originate from intermediate cycloadducts of cyclohexene and theexo-enols of the cyclic 1,3-diketones. The yields decrease with increasing polarity of the solvent. In solution2 and5 are in equilibrium with the cyclic hemiacetales3 and6.

     

Investigation of 2-[(<Emphasis Type="Italic">E</Emphasis>)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3H-indolium as a new highly sensitive reagent for the spectrophotometric determination of nitrophenols

A new, simple, rapid, and sensitive spectrophotometric method has been developed for the determination of nitrophenols [picric acid (PA); dinitrophenols (DNP)] in wastewater samples. The method is based on the reaction of nitrophenols with 2-[(E)-2-(4-diethylaminophenyl)-1-ethenyl]-1,3,3-trimethyl-3 H-indolium chloride reagent to form the colored ion associates, which are extracted by organic solvents. The molar absorptivity of the ion associates of PA with the investigated reagent ranges from 8.3×10⁴ to 11.3×10⁴ L mol^–1 cm^–1, depending on the extractant. Because only PA is extracted in an acidic medium with the investigated reagent, but both PA and DNP are extracted in an alkaline medium, it is possible to determine both substances in a mixture. Appropriate reaction conditions have been established. The absorbance of the colored extracts obeys Beers law in the range of 0.04–4.58 mg L^–1 PA, 1.0–18.4 mg L^–1 2,4-DNP and 1.2–14.7 mg L^–1 2,6-DNP, respectively. The limit of detections, calculated from a blank test (n=10; P=0.95), are 0.05 mg L^–1 PA, 0.9 mg L^–1 (2,4-DNP), and 1.1 mg L^–1 (2,6-DNP), respectively.     

Interaction of 4-Isopropoxalyl-1,5-diphenyl-2,3-dihydro-2,3-pyrroledione with Thiosemicarbazide: Synthesis and Crystal and Molecular Structure of (3aS*)(4R*)(6aR*)-4,6a-dihydroxy-4-isopropoxycarbonyl-1-thiocarbamoyl-3,5-diphenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-d]pyrazol-6-one

4-Isopropoxalyl-1,5-diphenyl-2,3-dihydro-2,3-pyrroledione reacts with thiosemicarbazide to form (3aS*)(4R*)(6aR*)-4,6a-dihydroxy-4-isopropoxycarbonyl-1-thiocarbamoyl-3,5-diphenyl-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-d]pyrazol-6-one. The molecular and crystal structure of the latter was studied by single crystal X-ray diffraction.     

Solvent-free Synthesis of Dihydrofuran-fused [60]Fullerene Derivatives by High-speed Vibration Milling

Solvent-free organic reactions have been attracting great interest of chemists due to the elimination of the usage of harmful organic solvents,low costs,and simplicity in the procedure1.Solvent-free mechanochemical reactions of fullerenes were explored and are significant for the reactions of fullerenes because the low solubility of fullerenes in common organic solvents requires large quantity of organic solvents and some novel fullerene reactions could only occur in the solid-state reaction2.…     

Synthesis and structure of anhydrodimers of salicylaldehydes

Anhydrodimers have been synthesized by reactions of salicylaldehyde and 3,5-di-tert-butylsalicylaldehyde with SOCl₂ or PCl₅. A mechanism of condensation has been proposed, and the molecular structure of dibenzo-2,6,9-trioxabicyclo[3.3.1]nona-3,7-diene has been determined by X-ray structural analysis.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1549–1551, August, 1995.The work was supported by the Russian Foundation for Basic Research (Project No. 94-03-08653).