Direct Catalytic Asymmetric Addition of α-Fluoronitriles to Aldehydes

A fluorine-containing tetrasubstituted stereogenic center is a highly valued structural feature in medicinal chemistry. Herein, we describe the direct coupling of racemic α-fluoronitriles and aldehydes promoted by a chiral Cu^I/Barton's base catalytic system, delivering α-tetrasubstituted α-fluoro-β-hydroxynitriles with satisfactory stereoselection. The stereochemical course was positively biased by the combined use of asymmetrical achiral thiourea as a supplementary ligand for Cu^I, which significantly enhanced the stereoselectivity. Both aromatic and aliphatic aldehydes were implemented to provide densely and stereoselectively functionalized chiral building blocks with aliphatic and aromatic tails.     

应用FTIR光谱研究不同取代苯胺对O－乙基－N－异丙基（取代硫脲基）硫代磷酰胺酯生成反应的影响

应用ＦＴＩＲ光谱研究不同取代苯胺对Ｏ－乙基－Ｎ－异丙基（取代硫脲基）硫代磷酰胺酯生成反应的影响何兰龄，赖城明，林，徐谨民，王永泰，杨华铮，吴烨（南开大学化学系，天津，３０００７１）（南开大学中心实验室）（南开大学元素有机化学研究所）关键词ＦＴＩＲ，取...     

GC/MS解析中二苯硫脲的中性丢失

温和条件常温常压下 ,苯胺与CS2 在AlCl3 催化作用下反应 ,对反应混合物用乙醇进行重结晶获得白色片状晶体 ,GC/MS分析表明该晶体为异硫氰酸苯酯。然而 ,用熔点测定、HPLC/MS/MS ,FTIR ,UV和1HNMR等手段对此晶体进行分析 ,确定其为二苯硫脲。结合GC/FTIR谱图 ,研究了二苯硫脲的质谱裂解机理。实验结果表明二苯硫脲质谱裂解中可能发生了中性丢失 ,丢失了中性分子苯胺 ,生成的异硫氰酸苯酯分子离子由于π电子共轭而致稳。此机理同样能合理解释二苯脲和二萘硫脲的GC/MS谱图中只出现异氰酸苯酯和异硫氰酸萘酯分子离子峰的现象。     

硫脲在铂电极表面吸附行为的表面增强拉曼光谱研究

本文通过电化学方法有效抑制了硫脲在铂电极表面的解离,从而实现了用SERS技术研究粗糙铂电极表面硫脲的吸附行为。结果表明,硫脲分子是以硫端斜躺吸附在电极表面,随着电位变负渐渐转为直立。     

N'-(4,6-二取代嘧啶-2-基)氧化烟酰硫脲的合成与生物活性测定

合成并表征了9种未见文献报道的N'-(4,6-二取代嘧啶-2-基)氧化烟酰硫脲衍生物3, 结构经IR, ¹H NMR, 元素分析得到确证. 初步的生物活性测试表明化合物3a具有较好的除草活性, 化合物3b具有一定的杀虫活性.     

Studies on the adsorption behaviors of Pb(II) onto an acyl-thiourea resin

In this paper, an acyl-thiourea resin (PIDTR) was synthesized and its adsorption performances to Pb(II) were investigated by adsorption tests, scanning electron microscopy (SEM), Fourier transform infrared spectra (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses. A pH of 6.0 was found to be the optimum pH to obtain the maximum adsorption capacity in 12 hours of equilibration time. The Langmuir model was well fitted to the adsorption data with adsorption capacity of 0.756?mmol?·?g^?1. The adsorption kinetics showed that the adsorption process experienced liquid film diffusion and chemical reaction. The thermodynamic studies indicated that the adsorption for Pb(II) was spontaneous and endothermic. The results of SEM suggested that Pb(II) adsorbed on the surface of PIDTR. The FTIR and XPS analyses further confirmed Pb(II) might chemisorb onto PIDTR surfaces and N–Pb, O–Pb, and S–Pb were formed with the breakage of C?O, C?S, and N-H bonds in the PIDTR molecule.     

Quinuclidine-Thiourea Inclusion Compound. A Perfect van der Waals Cavity

Thiourea reacts with 1-azabicyclo[2.2.2]octane (quinuclidine, Q) in methanol at room temperature leading to the formation of Q(3-thiourea).Single crystal X-ray diffraction analysis shows that the product has a rhombohedral structure, = = 90°, = 120°,a = b = 15.9371(2),c = 12.4248(2),which may bedescribed as a thiourea matrix defining hexagonal channels where the quinuclidine molecules are located. The ¹³C-cross polarisation magic angle spinning (CP-MAS) study indicates that the guest inside the cavities has high conformational, rotational and translational mobility at room temperature. Thermal studies indicate that the structural identity of the thiourea matrix remains after a partial loss of amine, and this result suggests that the thiourea-amine inclusion compound possesses an open host structure, or that a topotactic process is associated.     

酰基硫脲分子内氢键与取代基效应的定量关系

对２３个Ｎ－二茂铁甲酰基－Ｎ’－芳基硫脲和４个Ｎ－苯甲酰基－Ｎ’－芳基硫脲的δβ－ＮＨ与各种取代胺的碱性强度ｐＫｂ及苯环下取代基常数σ进行了系统的定量关系研究。结果提示了此类化合物的分子内氢键与取代基效应之间的定量关系。     

氯化四硫脲合钯配合物Pd[(NH2)2CS]4Cl2的晶体结构

The title compound， Pd[(NH₂)₂CS]₄Cl₂， has been synthesized and structurally characterized. It crystallizes in orthorhombic， Pna2(1) space group ， with M_r=481.79(C₄H₁₆Cl₂N₈PdS₄)， a=12.943(3)， b=8.283(2)， c=15.148(3)?， V=1623.9(6)?³， Z=4. The Pd(Ⅱ) ion has an square-planar geometry， and is coordinated by four S atom donors from four thiourea molecules. The two Cl^- anions found in the apical position balance the charge. In the solid state， the title compound forms three dimensional network structures through hydrogen bonds. The inter-molecular hydrogen bonds connect the {Pd[(NH₂)₂CS]₄}²⁺ and chloride ion to contribute to the stability of the structure. CCDC： 193379.     

N-(5-对溴苯氧甲基-1,3,4-噻二唑-2-基)-N′-芳氧乙酰基硫脲的合成与生物活性

2-氨基-5-对溴苯氧甲基-1,3,4-噻二唑与芳氧乙酰基异硫氰酸酯反应,合成了9种新的芳氧乙酰基硫脲。其结构经1H NMR,IR和元素分析确证。初步的生物活性实验结果表明,部分化合物具有较好的植物生长调节活性。