柱前衍生法在氨基酸分析测定中的应用

介绍了目前柱前衍生法分析氨基酸常用的几类衍生试剂及相应的衍生方法,并且比较了各类柱前衍生试剂的优缺点,对近期氨基酸分离分析中的色谱检测方法做了系统综述。     

氨基酸分子构象稳定性与光电离解离动力学的氢键效应*

本文综述了氨基酸分子内氢键种类和数目对分子构象稳定性和光电离解离动力学的各种效应：得出分子内含有N···H–O和C=O···H–O氢键的构象具有较高的热力学稳定性; N···H–O氢键导致分子第一电离能数值的增加,同时可以导致电离过程中的质子转移以及后续二氧化碳释放的解离过程。氨基酸分子正离子的稳定性或碳碳化学键断裂解离动力学也不尽相同,丝氨酸分子在电离阈值附近解离过程中表现出奇特的立体效应。     

直接电导检测-离子排斥色谱法测定芳香族羧酸

研究了直接电导检测-离子排斥色谱法分离测定芳香族羧酸(邻苯二甲酸、水杨酸、苯乙酸、对羟基苯甲酸、苯甲酸和邻甲苯甲酸)。以Shim-packSCR-102H色谱柱为分离柱,H2SO4为流动相,考察了流动相浓度、色谱柱温度、流速对分离和测定芳香族羧酸的影响,确定最佳色谱条件为:0.08mmol/LH2SO4作为流动相,柱温45℃,流速1.2mL/min。所测芳香族羧酸的检出限为0.07～0.98mg/L;相对标准偏差在2.6%以下(n=5);回收率为95.8%～100.1%。本方法用于酱油样品的分析,得到满意结果。     

微波辐射下5-取代-2-硫代海因衍生物的合成

微波辐射下, 由硫氰酸铵与α-氨基酸通过两步反应合成了11种5-取代-2-硫代海因衍生物, 并用¹H NMR, IR和元素分析确证了中间产物和终产物的结构. 对比常规加热方法, 微波辐射具有反应时间短(4 min), 每步反应产率高(85%～93%)的优点. 同时对合成化合物2h的反应历程进行了讨论.     

邻菲咯啉合铜配合物与牛血清白蛋白的相互作用

利用荧光光谱法研究了两种配合物,[Cu（phen）（L-Phe）（H2O）]ClO4（1）（L-Phe为L-苯丙氨酸根）和[Cu（phen）（Gly）（H2O）]ClO4·2．5H2O（2）（Cly为甘氨酸根）,与牛血清白蛋白（BSA）的相互作用。结果表明,牛血清白蛋白的荧光强度随着配合物浓度的增大而逐渐降低,配合物（2）与BSA的结合常数大于配合物（1）与BSA的结合常数,牛血清白蛋白对配合物的结合位点数为1,荧光猝灭作用机理为静态猝灭．     

Functionalization of 4,6-dinitro-2-phenylindole at position 7

Transformation of the amino group in 7-amino-1-methyl-4,6-dinitro-2-phenylindole afforded a number of new 7-R-4,6-dinitroindoles and a first representative of a novel tricyclic heteroaromatic system of [1,2,5]oxadiazolo[4,3-g]indole. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1508–1511, July, 2008.     

Two new acids from mangrove endophytic fungus (No. ZZF13)

Two new acids 1 and 2, together with a known compound, purpactin A (3), were isolated from endophytic fungus No. ZZF13. Their structures were elucidated on the basis of 1D, 2D NMR, and HREIMS spectra. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp.336-337, July-August, 2008. Original articlesubmitted April 24, 2007.     

The Mitsunobu 1-O-esterification of 1-hydroxy-3-phenyl-1H-quinoxalin-2-one 4-oxide

1-Hydroxy-2-oxo-3-phenyl-1,2-dihydroquinoxaline 4-oxide under conditions of the Mitsunobu reaction reacts with alcohols giving the corresponding esters at the hydroxy group in position 1. Other representatives of hydroxamic acids such as 1,4-dihydroxyperhydroquinoxaline-2,3-dione and 1,4-dihydroxy-3,3,6,6-tetramethylpiperazine-2,5-dione undergo destruction under these conditions. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1240–1243, June, 2008.     

Stabilities and coordination modes of histidine in copper(II) mixed-ligand complexes with ethylenediamine,diethylenetriamine or N,N,N′,N″,N″-pentamethyldiethylenetriamine in aqueous solution

Solution equilibrium studies on the Cu(II)–polyamine–histidine ternary systems (polyamine: ethylenediamine (en), diethylenetriamine (dien), N,N,N′,N″,N″-pentamethyldiethylenetriamine (Me₅dien)) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the mixed-ligand complexes with [Cu(A)(His)]⁺ stoichiometry in all studied systems. Additionally, in the systems with dien and Me₅dien protonated [Cu(A)(H–His)]²⁺ species also exists in acid solution. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(His)]⁺, the geometry slightly deviated from square pyramidal for the [Cu(dien)(His)]⁺ and strongly deviated from square pyramidal towards trigonal bipyramidal for the [Cu(Me₅dien)(His)]⁺ species. The coordination modes in these mixed-ligand complexes are discussed.     

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.