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1.
新型金属卟啉的合成及其对大肠杆菌生长代谢的抑制作用   总被引:13,自引:1,他引:12  
以5,10,15,20-四(对羟基苯基)卟啉(2)为原料,合成并表征了一系列 水溶性和非水溶性的金属卟啉。使用LKB 2277热活性监测器测定了大肠杆菌在金属 卟啉4a ~ 4f和7a ~ 7f作用下的生热曲线,得到了不同金属卟啉在不同浓度下大 肠杆菌生长代谢的生热速率常数k,最大发热功率p_(max)和最大发热功率的出现时 间t。结果发现,含有吡啶溴化盐的水溶性金属卟啉7a ~ 7f对大肠杆菌生长代谢 的抑制活性要明显大于含有酯基的金属卟啉4a ~ 4f。  相似文献   

2.
报道了6-O-对甲苯磺酰基-1,2:3,4-二-O-异亚丙基-α-D吡喃型半 乳糖(3)与取代的3-巯基三唑或5-巯基四唑4a-4c或5a-5f的亲核取代反应,合 成了9个6-S-(取代的三或四唑杂环基)-1,2:3,4-二-O-异亚丙基-α- D吡喃型半乳糖(6a-6i),通过元素分析,IR,NMR和MS确证了上述化合物的结构 ,并经分子模型计算进行了其构象分析。  相似文献   

3.
金属卟啉能够在温和条件下催化烃类的部分氧化,且有较好的选择性因此,金属卟啉的仿生催化研究不仅具有重大的理论意义,亦有广阔的应用前景,现已成为仿生催化领域中人们极感兴趣的工作,但是,金属卟啉化合物催化领域中人们极感举的工作,但是,金属卟啉化合物催化烃类氧化时,一般须使用诸如PhIO、NaClO、H2O2这样的单氧原子供体作氧化剂,或使用诸如锌粉、Vc等还原剂加分子氧体系,从实际应用来看,单独使用分子氧为氧化剂用于金属卟啉催化烃类氧化是最具诱惑力的。然而,在这方面的研究报导仅见于多卤代卟啉,我们在探索单独用空气作用氧化剂进行金属卟啉仿生催化时发现,象乙苯这样含有相对较为活泼的C-H键的分子,在μ-氧化双锰卟啉([TPPMn]2O)的催化下,亦能够直接被分子氧氧化,本工作考察了各种因素对该反应的影响。  相似文献   

4.
苯胺及取代的苯胺和Meldrum’s acid在固相无催化剂条件下反应,合成了丙二酸单苯酰胺(1a-1f),收率81.0%~92.2%.化合物1a-1f在Eaton试剂(五氧化二磷+甲基磺酸)或多聚磷酸为环化试剂的条件下发生Friedel—Crafts分子内环化反应,以63.2%~93.8%和56.5%~81.3%的收率方便地得到4-羟基喹啉-2-酮衍生物(2a-2f).产物的结构通过IR,^1H NMR和元素分析得以证实.  相似文献   

5.
刘方明  王宝雷等 《化学学报》2002,60(6):1095-1101
α,β-不饱和酮(1a-1e)与邻氨基苯硫酚反应,得到含2-苯基-1,2,3-三唑基的1,5-苯并硫氮杂Zhuo(2a-2e),然后以其为原料与烯酮“现场”进行[2 2]环加成,合成出一系列含2-苯基-1,2,3-三唑基的β-内酰胺并合的1,5-苯并硫氮杂Zhuo衍生物(3a-3j),产物经^1H NMR,IR,元素分析及MS加以确证。  相似文献   

6.
李悦生 《高分子科学》2011,29(5):627-633
Mono salicylaldiminato vanadium(Ⅲ) complexes(1a-1f)[RN = CH(ArO)]VCl2(THF)2(Ar = C6H4(1a-1e),R = Ph,1a;R = p-CF3Ph,1b;R = 2,6-Me2Ph,1c;R = 2,6-iPr2Ph,1d;R = cyclohexyl,1e;Ar = C6H2tBu2(2,4),R = 2,6-iPr2Ph, 1f) and bis(salicylaldiminato) vanadium(Ⅲ) complexes(2a-2f)[RN = CH(ArO)]2VCl(THF)x(Ar = C6H4(2a-2e),x = 1 (2a-2e),R = Ph,2a;R =p-CF3Ph,2b;R = 2,6-Me2Ph,2c;R = 2,6-iPr2Ph,2d;R = cyclohexyl,2e;Ar = C6H2tBu2(2,4),R = 2,6-iPr2Ph,x = 0,2f) have been evaluated as the active catalysts for ethylene/1-hexene copolymerization in the presence of Et2AlCl.The ligand substitution pattern and the catalyst structure model significantly influenced the polymerization behaviors such as the catalytic activity,the molecular weight and molecular weight distribution of the copolymers etc.The highest catalytic activity of 8.82 kg PE/(mmolV·h) was observed for vanadium catalyst 2d with two 2,6-diisopropylphenyl substituted salicylaldiminato ligands.The copolymer with the highest molecular weight was obtained by using mono salicylaldiminato vanadium catalyst 1f having ligands with tert-butyl at the ortho and para of the aryloxy moiety.  相似文献   

7.
以H2O2为氧化剂,研究了离子液体为催化剂和溶剂,环己烯氧化生成反-1,2-环己二醇的反应。 考察了不同咪唑型离子液体、反应时间、反应温度和H2O2用量等对产率和选择性的影响, 实验结果表明,在7种咪唑型离子液体催化体系中,阳离子为咪唑环上含有1或2个羧基,阴离子为[PF6]的离子液体催化效果较好。 反应温度为100 ℃,n(H2O2)∶n(Cyclohexene)=1.1∶1,反应5 h时,离子液体c(0.60 g,2.1 mmol)催化生成的反-1,2-环己二醇的产率和选择性分别为95%和97%,而离子液体f(0.20 g,0.6 mmol)催化生成的反-1,2-环己二醇的产率和选择性分别为84%和90%,从离子液体的用量来看,含2个羧基的离子液体f的催化效率更高。  相似文献   

8.
综述了水溶性金属卟啉作为催化剂应用于均相或非均相的催化反应的研究进展,重点介绍了水溶性金属卟啉在水或水与有机溶剂混合介质中催化底物氧化反应的催化性能,其中包括烷烃的羟基化,烯烃的环氧化,含氧、含硫及含氮化合物的氧化反应.另外水溶性金属卟啉还可用于催化Suzuki-Miyaura反应、氧化偶联反应、C=C氧化断裂反应等.水溶性金属卟啉催化剂具有水溶性、催化效率高、反应条件温和等优点,因此将在催化反应特别是氧化反应中得到更广泛的应用.  相似文献   

9.
盘状液晶分子中引入氟代烃链并利用疏氟效应(fluorophobic effect)能有效稳定分子的柱状堆积;低对称性的盘状分子有较低的熔点和宽的介晶相温度范围.基于此,本文设计并合成了一系列半氟酯链的不对称苯并菲化合物C18H6(OCnH2n+1)4(OCH3)(O2CC2H4C6F13)(1),及相对应的不含氟化合物C18H6(OCnH2n+1)4(OCH3)(O2CC8H17)(2),n=4—8.化合物结构通过核磁和质谱表征.介晶性通过差示扫描量热法和偏光显微镜进行了研究.结果显示:化合物均为柱状互变热致液晶.含氟链化合物1a—1e与相对应的化合物2a-2e比较,有更高的熔点和清亮点.合成的多数化合物为室温液晶.  相似文献   

10.
高文涛  杨锦宗 《有机化学》1999,19(4):405-408
报道了采用溴氧化3-异丙烯基卓酚酮和3-肉桂酰基卓酚酮合成杂环并卓酮化合物的新方法。3-异丙烯基卓酚酮5位偶联产物1a-1f和3-肉桂酰基卓酚酮5位偶联产物3a-3d分别在吡啶介质中与过量溴作用生成5-取代苯偶氮基-7-溴-3-甲基-8-氢环庚并呋喃-8-酮2a-2f和6-取代苯偶氮基-2-苯基-8-溴-4,9-二氢环庚并吡喃-4,9-二酮4a-4d。  相似文献   

11.
The changes in the thermodynamic functions of the sorbents were calculated for the first time from measurements of the deformations of vermiculite during the sorption of water vapor and adsorption-calorimetric data.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Institute of Colloid Chemistry and the Chemistry of Water, Academy of Sciences of the Ukraine, 252180 Kiev. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 6, pp. 1270–1275, June, 1992.  相似文献   

12.
We have summarized results of many experimental investigations of the thermodynamics of ionization of H2O(liq.) from 0–300°C and from 1.0 atm to nearly 8000 atm. Results of these investigations (equilibrium constants, enthalpies of ionization, heat capacities, partial molal volumes, and compressibilities) have been used for a number of thermodynamic calculations. It is particularly noteworthy that it is possible to use thermal data from 0–145°C with an equilibrium constant for 25°C in calculating reasonably accurate equilibrium constants for temperatures as high as 300°C. Similarly, it is possible to use volumetric data that refer to 1.0 atm in calculating useful equilibrium constants that apply for pressures as high as 2000 atm.Much of the work reported here was done while the author was on leave at the University of Lethbridge.  相似文献   

13.
Enthalpies of solution in water H sol o and enthalpies of sublimation H sub o were determined for a number of crystalline derivatives of uracil: 1,6-dimethyluracil (m 2 1,6 Ura), 1,3,6-trimethyluracil (m 3 1,3,6 Ura), 6-ethyl-1,3-dimethyluracil (e6m 2 1,3 Ura), 6-propyl-1,3-dimethyluracil (pr6m 2 1,3 Ura) and 6-butyl-1,3-dimethyluracil (but6m 2 1,3 Ura). Standard enthalpies of hydration H hydr o and standard enthalpies of interaction H int o of the solutes with their hydration shells were calculated. The data obtained show that dependence of H int o on the number of-CH2- groups of n-alkyl chain added upon substitution of diketopyrimidine ring is nonlinear. This finding is discussed in connection with results of X-ray diffraction structure determinations for the crystalline compounds.  相似文献   

14.
宋华强 《化学教育》2019,40(1):27-30
以“质量守恒定律”为例,选取科学革命、科学问题、科学实验、归纳与重复、解释与预测等几个视角对科学课堂教学的各个环节进行了分析。通过分析,各环节中所蕴含的科学哲学内容得以显现,对科学课堂教学的认识更为全面,对科学本质的认识更加深刻。  相似文献   

15.
We have made calorimetric measurements of enthalpies of dilution of aqueous iodic acid and have used these results for evaluation of the standard enthalpy of ionization of HIO3(aq.). We have also made calorimetric measurements of enthalpies of addition of perchloric acid solution to aqueous solutions of KIO3, KNO3, NaIO3, and NaNO3 and have used these results to obtain further values for the standard enthalpy of ionization of HIO3(aq.). On the basis of all these results, we have selected Ho=–660±125 cal-mole–1 as the best available standard enthalpy of ionization of HIO3(aq.) at 298.15°K, compared to the previously accepted –2400 cal-mole–1. Using the best available K=0.157 for ionization, we also obtain Go=1097 cal-mole–1 and So=–5.9 cal-oK–1-mole–1 for ionization of HIO3(aq) at 298.15°K.On study leave from Department of Inorganic and Analytical Chemistry, LaTrobe University, Bundoora, Victoria, 3083, Australia, to University of Lethbridge.On study leave from Department of Chemistry, University of Wollongong, Wollongong, N.S.W. 2500, Australia, to University of Lethbridge.  相似文献   

16.
The unsaturated and saturated pressures of gallium trichloride vapor were measured by the static method with membrane-gauge manometers in wide pressure (0.2–760 Torr) and temperature (313–1071 K) intervals. Scanning calorimetry was used to determine the thermodynamic characteristics of GaCl3 fusion. The thermodynamic characteristics were obtained for sublimation, fusion, vaporization, and association in the vapor of GaCl3 molecules. The enthalpies of formation and the absolute entropies of GaCl3 in the liquid and gaseous phases and Ga2Cl6 in the gaseous phase were calculated using literature data. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1266–1269, July, 2007.  相似文献   

17.
Based on the model of spatial separation of the dissolution and passivation of hydrophilic metals, the effect of strong specific adsorption of anions on the shape of curves for the relaxation of anodic current of metals in acid solutions after switching an anodic activation pulse off is considered by using iron as an example.  相似文献   

18.
Enthalpies of solution in water, H sol o , and of sublimation, H subl o , were determined experimentally for a number of crystalline N-methyl adenines: m6Ade, m 2 6,6 Ade, m9Ade, m 2 6,9 Ade, and m 3 6,6,9 Ade. Derived standard enthalpies of hydration H hydr o , were corrected for the calculated cavity terms H cav o to yield enthalpies of interaction H int o of the solutes with their hydration shells. The increments of H int o per unit area of the water-accessible molecular surface S B , H int o (CH3)/S B (CH3), for the particular methyl groups: is considered to be the net effect of the gain in the energy resulting from van der Waals' interactions and of the loss in the energy due to polar interactions upon methyl substitution. It proved to vary somewhat numerically in agreement with the theoretically predicted hydration schemes of adenine. Comparison of H int o /S B value for adenine with those previously determined for uracil and thymine indicates that the aminopurine moiety is less hydrated than the diketopyrimidine ring.  相似文献   

19.
锌在植物中的形态及生理作用机理研究进展   总被引:27,自引:1,他引:26  
对锌在植物中的形态及锌在植物生理过程中的作用机理进行了综述和讨论,表明锌对碳水化合物代谢,蛋白质代谢,植物生长素代谢及细胞膜的功能和结构有很大影响。此外,锌与植物病害也有很大关系。  相似文献   

20.
An equation for the internal pressure acting on an adsorbate in micropores was obtained on the basis of the assumption that the chemical potential of an adsorbate in micropores is equal to that in an equilibrium gas phase and using the Dubinin-Radushkevich equation. The empirical relation between the characteristic adsorption energy and the half width of pores was expressed in terms of internal pressure and diameter of adsorbate molecules. The two-dimensional pressure was calculated for micropores with plane-parallel walls, where the width of a micropore coincides with the diameter of an adsorbate molecule. The results obtained were compared with the two-dimensional pressure of a monolayer on a free planar surface for an adsorbate and adsorbent of the same nature.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1928–1930, October, 1995.  相似文献   

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