羟胺合成哌嗪类化合物的研究

本文讨论了以羟胺为原料环合得到哌嗪及其衍生物。筛选得到了镍、铜、铬、锌、锰／氧化铝载体催化剂，并通过试验得到了最佳反应条件，使哌嗪的收率达95％以上。并根据类似方法合成了2-甲基哌嗪和顺式-2，6-二甲基哌嗪。     

哌嗪的生产应用和市场

综述了哌嗪的合成技术和应用开发现状,分析了哌嗪的市场前景。     

Antibacterial activity and mechanism of piperazine polymer

Piperazine polymers poly(ethylenediaminetetraacetic dianhydride-co-piperazine) (PE) and MGF-Ct24E-modified poly(ethylenediaminetetraacetic dianhydride-co-piperazine) (PEM) showed good antibacterial activity. Considering their different applications, the effects of time, pH, and inoculation concentration of these antibacterials against Escherichia coli (E. coli) in unique environments were evaluated in this study. The results indicated that the MIC and MBC values of the polymers increased after the introduction of MGF-Ct24E into PE, but the two types of polymers still exhibited good antibacterial activity in a short time period under acidic conditions. In addition, we investigated the effect of the piperazine polymers on bacterial cell structure. It was clear that PE and PEM could destroy the bacterial cell wall, cell membrane and DNA, and their specific mechanism may be different. For PE, its carboxyl group could react with peptidoglycans on the E.coli cell wall to form holes on the bacterial surface, allowing PE to penetrate into the bacterial cell to damage DNA. For PEM, the alkaline MGF-Ct24E could adsorb E.coli and make it shrink, meanwhile, the PE component created small holes on the bacterial walls and membranes, and inserted into the bacteria to result in bactericidal effect. These findings reveal the potential usefulness of PE and PEM in biomedical applications.     

盐酸曲美他嗪的合成

研究一种冠状动脉血管扩张剂盐酸曲美他嗪的合成方法。以六水哌嗪为起始原料,经酰化、Mannich反应、水解、成盐反应制得目标化合物。目标化合物的结构经熔点测定、红外及1 H-NMR谱确证,总收率为29.2%,经HPLC检测纯度为98.5%。该合成方法成本较低、操作简便、条件温和,适于工业生产。     

4,5,6,7-四氢吡唑并[1,5-a]哌嗪-3-甲酸乙酯的合成

以4-氯-3-氧代丁酸乙酯为原料,经与叔丁醇钾醚化、DMF-DMA缩合、水合肼环合、脱叔丁基、羟基氧化、还原氨化、分子内环合以及氢化脱苄等反应合成了标题化合物。并对其中关键的羟基氧化反应和分子内环化反应的工艺条件进行了优化,获得了较优的工艺条件:在羟基氧化反应中以二氧化锰为氧化剂、氯仿为溶剂;在分子内环化反应中以甲基磺酰氧基(OMs)为离去基团。目标化合物的总收率为39.5%,其结构经~1HNMR、~(13)CNMR、MS和元素分析进行了确定。     

1,4-二硝基呋咱并[3,4-b]哌嗪(DNFP)的合成

设计合成了高能量密度材料1，4-二硝基呋咱并[3，4-b]哌嗪（DNFP）。即以N，N＇-二叔丁基乙二胺为起始原料，低温条件下与二氯乙二肟缩合环化生成1，4-二叔丁基哌嗪-2，3-二酮肟（PDO—tB），而后在氢氧化钠的乙二醇溶液中高温反应脱水环化得1，4-二叔丁基呋咱并[3，4-b]哌嗪，经98％硝酸和硫酸的混酸体系硝解合成出DNFP，总收率32．6％，采用红外光谱、核磁共振谱、元素分析对DNFP和中间体结构进行了表征；改进了PDO—tB的合成工艺条件，加料方式由一次性加入改为缓慢滴加，并确定了适宜的冷浴温度为-18℃；研究了不同硝解体系对反应的影响，确定了适宜的硝解体系为硝硫混酸，硝解收率为61．7％。     

Electrochemical properties of two-component polymers of palladium and pyrrolidine and piperazine derivatives of C60

Redox-active films have been generated via electrochemical reduction in a solution containing palladium(II) acetate and [C₆₀]fullerene, or derivatives of C₆₀. The C₆₀ derivatives include piperazine (piperazine-C₆₀), pyrrolidine (CH₃-pyr-C₆₀), and a pyrrolidine salt, [(CH₃)₂-pyr-C₆₀]⁺ attached to the fullerene unit. In these films, fullerene moieties are covalently bonded to palladium atoms to form a polymeric network. The polymer yields involving the piperazine and pyrrolidine derivatives of C₆₀ are significantly lower than the yield of the C₆₀/Pd film. The CH₃-pyr-C₆₀/Pd and [(CH₃)₂-pyr-C₆₀]⁺/Pd films are electrochemically active in the negative potential region due to the reduction of the fullerene moiety. Reduction of the CH₃-pyr-C₆₀/Pd film is accompanied by the transport of supporting electrolyte cations from the solution into the film. In the first reduction step of the [(CH₃)₂-pyr-C₆₀]⁺/Pd film, both cations and anions of the supporting electrolyte are involved. The piperazine-C₆₀/Pd film exhibits electrochemical activity at both negative and positive potentials. In the negative potential region, reduction of the fullerene cage takes place. Oxidation of the piperazine moiety is responsible for the observed current in the positive potential range. Here, the oxidation process of this polymer is significantly influenced by the presence of metallic palladium particles in the film.     

Synergistic flame retardancy of ZnO and piperazine pyrophosphate/melamine cyanurate in polypropylene

In order to improve the flame retardant efficiency and smoke-suppression of piperazine pyrophosphate/melamine cyanurate (PPAP/MCA) in PP, the synergism of ZnO and PPAP/MCA was investigated by limiting oxygen index (LOI) determination, UL-94 test, and cone calorimetry test (CCT). It is found that ZnO performs an exceptional synergism in flame retardant effect and inhibition on the flame propagation. Besides, ZnO can significantly inhibit the production of the smoke and CO. The TGA of the PP composites, the component and structure analysis of the heated composites and CCT residues reveal that ZnO performs the synergism primarily by the following modes: ZnO promotes obviously the charring of the composite, and improves the thermal stability as well as the strength of the intumescent layer, which brings about an improved flame retardant property and inhibiting ability on the flame propagation.     

CO2 Capture Using Activated Amino Acid Salt Solutions in a Membrane Contactor

An activated solution based on amino acid salt was proposed as a CO₂ absorbent. Piperazine (PZ) was selected as an activating agent and added into the aqueous glycine salt to form the activated solution. A coupling process, which associated the activated solution with a PP hollow fiber membrane contactor, was set up. An experimental and theoretical analysis for CO₂ capture was performed. The performances of CO₂ capture by the coupling process were evaluated using the PZ activated solution and the non-activated glycine salt solution. A numerical model for the simulation of the hollow fiber membrane gas–liquid mass transfer was developed. Typical parameters such as outlet gas phase CO₂ concentration, capture efficiency, and mass transfer coefficient for the activated solution were determined experimentally. The effects of operation temperature and liquid CO₂-loading on mass transfer coefficient and capture efficiency were discussed in this work. Axial and radial concentration profiles of CO₂ in the fiber lumen and mass transfer flux were simulated by the model. Results show that the performances of the PZ activated glycine salt solution are evidently better than that of the non-activated glycine salt solution in the membrane contactor for CO₂ capture. Elevation of the operation temperatures can enhance the overall mass transfer coefficient. The activated solution can maintain higher capture efficiency especially in the case of high CO₂-loadings. The gas phase CO₂ concentration with the activated solution is lower than that with the non-activated solution whether along axial or radial distances in the fiber lumen. The model simulation is validated with experimental data.     

脂肪胺合成哌嗪的几种方法

介绍了由脂肪胺合成哌嗪的几种方法。