Fmoc保护氨基酸与Wang树脂的缩合反应

研究了保护氨基酸、Wang 树脂取代度、树脂粒度、搅拌方式对Fmoc-氨基酸-Wang树脂连接效率的影响. 结果表明, 保护氨基酸分子量的大小会因产生不同的位阻而影响缩合反应的效率, 分子量越小缩合效率越高; Wang树脂的取代度较高时, 已缩合的氨基酸给后续保护氨基酸的缩合形成阻碍, 使缩合效率降低; 粒径较小和搅拌较好时, 对保护氨基酸的粒内外扩散有利, 可提高反应速度和缩合效率.     

10-甲基吖啶苯酚酯衍生物的合成、表征及化学发光特性

吖啶-9-羧酸苯酚酯是一类效率较高的化学发光试剂.其结构一般有两部分组成,吖啶环发光部分和9-羧酸苯酚酯离去基团.本文对离去基团进行修饰,分别在离去基团苯酚部分的2,5或2,6位引入取代基CF₃、NO₂、Br、CH₃,合成了4个新吖啶酯衍生物,并对它们的分子结构进行了表征.4个新化合物和模型化合物(无取代基)比较,均表现出较好的化学发光效率;发光动力学基本符合文献报道规律.而且化学发光法对其水解稳定性考察显示,取代基的电性和位阻是影响稳定性的两大因素.     

溶剂调控布洛芬乙烯酯酶促水解的立体选择性的热力学研究

采用高效液相色谱研究了不同溶剂体系中褶皱假丝酵母菌脂肪酶（CRL）催化布洛芬乙烯酯水解反应的立体选择性.研究发现,在单一溶剂体系中Eyring曲线呈线性,在10~50 ℃的实验温度内均呈S选择性;在混合溶剂体系中Eyring曲线呈非线性,且观察到不同的转变温度（T_inv）.研究还发现：在亲水性有机溶剂二氧六环/水均相混合溶剂体系中,Eyring曲线的T_inv处立体选择性E 值为极小值,在疏水性有机溶剂异辛烷/水两相混合溶剂体系中,T_inv处E 值为极大值,而在氯仿/水两相混合溶剂体系中,随着温度的变化,立体选择性发生了反转.     

羧酸甲乙酯中羰基17O-NMR化学位移研究

提出了计算羧酸甲乙酯中羰基¹⁷O-NMR化学位移的公式：δ_cal（¹⁷O）=360.0+Δα+Δβ+Δγ,通过线性回归法确定了22种取代基参数.经回归检验表明该公式计算结果置信度为99.5%,与实验值的偏差Δδ在5.0以内的羰基¹⁷O-NMR化学位移计算值~100%.     

Spectroscopic studies and crystal structure of a dimeric Zn(II) complex with diethyl (pyridin-2-ylmethyl)phosphate

The crystal structure of [Zn₂(2-pmOpe)₂Cl₄] (2-pmOpe?=?diethyl (pyridin-2-ylmethyl)phosphate) was determined by X-ray-diffraction method. The compound was also characterized by IR, far-IR, 1H, and ³¹P NMR spectroscopy. In this compound, 2-pmOpe is a bidentate N,O-bridging ligand and Zn(II) are slightly distorted tetrahedral ZnNOCl₂. Zn(II) ions are doubly bridged by the 2-pmOpe ligands, resulting in a dinuclear species. The structure is stabilized by intermolecular C–H?···?O and C–H?···?Cl hydrogen bonds. The spectral properties are in agreement with the structural data.     

Dissipation of the plant growth regulator hexanoic acid 2-(diethylamino) ethyl ester in pakchoi and soil

A rapid and simple method for determining the plant growth regulator hexanoic acid 2-(diethylamino) ethyl ester (DA-6) in pakchoi and soil using gas chromatography-mass spectrometry (GC-MS) has been developed. For this purpose, a single step was used to extract DA-6 with dichloromethane from aqueous-acetone extracts of vegetables and soil. Average recoveries of DA-6 in pakchoi and soil were between 85% and 104% at both spiking levels 0.01 and 0.1 mg kg^?1. Relative standard deviations (RSD) were less than 11% for all of the recovery tests. The degradation of DA-6 in pakchoi and soil was studied. The results showed that DA-6 degradation in pakchoi and soil coincided with C = 3.9903 e^{?0.0516 t} , C = 0.3476 e^{?0.0224 t} , respectively; the half-lives were 13.43 h and 30.94 h in pakchoi and soil in Beijing, respectively.     

First total synthesis of isoquinolinone alkaloid marinamide and its methyl ester

The first total synthesis of isoquinolinone alkaloid marinamide 1 and its methyl ester 2 was described. The key steps involved a regioselective Frieclel-Crafts reaction of 1-benzyl-1H-pyrrole to form the intermediate 8.     

Synthesis of Bicyclic Compounds Derived from 1,2,4-Benzotriazines

The synthesis of bicyclic compounds derived from benzo[1,2,4]triazines is described.     

Efficient and Alternative Approach for Preparation of O-Benzoyloximes Using Benzoyl Peroxide

Benzoyl peroxide has been used as a mild and efficient reagent for the preparation of benzoyl ester of oxime in moderate to good yields.