钕诱导番茄产生抗性的时间研究

采用盆栽试验研究了Nd3 在不同诱导时间对番茄叶抗性指标(过氧化物酶(POD)、多酚氧化酶(PPO)和苯丙氨酸解氨酶(PAL)活性、细胞膜透性、氧自由基(O2-·)产生速率和木质素含量)的影响.结果表明:从第3 d开始,Nd3 诱导提高番茄叶内PAL活性,第3d增幅也最大,达32.30%,维持时间为诱导后第3～5 d;Nd3 诱导后第1～2 d POD活性升高,第1 d增幅最大,维持时间是诱导后第1～2 d;Nd3 诱导后1～3 d,PPO活性升高,第1 d增幅最大,维持时间是诱导后第1～3 d;从诱导后第2 d开始,Nd3 降低细胞膜透性,第3 d时降幅最大,为54.33%,持续时间为诱导后第2～5 d;从第3 d开始,Nd3 诱导降低氧自由基产生速率,第4 d降幅最大,第3 d氧自由基产生速率最低,持续时间为诱导后第3～5 d;从第4 d开始,Nd3 诱导提高木质素含量,5 d时有继续升高的趋势.从不同诱导时间番茄叶PAL活性、细胞膜透性、氧自由基产生速率的变化来看,在Nd3 诱导的第3 d,番茄产生的抗性最强.     

镧对油菜抗病性相关酶活性的影响

通过水培试验,研究了La对与油菜抗病性相关的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)和多酚氧化酶(PPO)酶活性以及对膜脂过氧化产物丙二醛(MDA)含量的影响。结果表明:喷施0.3mg·kg-1的La3+油菜叶绿素含量显著增加,POD,CAT,SOD和PPO活性增高,MDA含量降低,但可溶性蛋白含量无显著变化。可见La具有诱导植株产生抗病性的作用。     

钕对番茄叶挥发性物质诱导效应的研究

以Nd3+诱导番茄叶,测定其对番茄叶挥发性物质组成和含量的影响。结果表明,番茄叶经60 mg.L-1Nd3+诱导120 h后,挥发性物质的总含量较对照组的增加57%;氧合脂类、萜类化合物、芳香族化合物的含量分别较对照组的提高73%,38%和32%。含量最高组分(E)-2-己烯醛较对照组的提高74%。含量显著性提高的组分还包括萜类化合物的β-水芹烯和α-石竹烯,芳香族化合物的丁子香酚,分别较对照组的提高129%,65%和309%。不同浓度的Nd3+均可促进挥发性物质的释放,且随诱导时间呈不同的变化趋势。一定浓度的Nd3+还可诱导番茄叶活性氧的释放以及几丁质酶和-β1,3-葡聚糖酶活力的提高。说明Nd3+可能通过提高番茄叶挥发性物质的含量,以增强其抗病能力。     

外源钕减轻了重金属镉对菹草的毒害作用

研究了不同浓度钕对菹草镉胁迫的缓解效应.结果表明,单一镉(10 mg·L-1)处理降低了菹草叶片抗氧化酶系超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)活性,丙二醛(MDA)含量升高,可溶性蛋白和叶绿素含量下降.用不同浓度钕处理后,明显减轻了这些症状,抗氧化酶活性均有所提高,与毒害对照相比,SOD、CAT及POD活性分别提高了14.0%～30.0%,8.8%～47.3%,4.6%～15.1%,并减轻了叶绿素和可溶性蛋白的降解,减缓了MDA的积累.随着钕浓度的进一步加大,缓解效应逐渐减弱,钕作用的最适浓度为10～15mg·L-1.     

稀土-其它过渡金属混合催化剂用于共轭双烯烃的聚合——Ⅳ.(NdCl_3+FeCl_3)·nphen-HAI(i-Bu)_2体系对异戊二烯的聚合

本文报道由(NdCl_3+FeCl_3)·nphen-HAl(i-Bu)_2催化体系引发异戊二烯聚合的结果。在适当Nd/Pe比下,该体系对异戊二烯聚合的活性可超过单一钕或铁催化剂的活性,同时随催化剂中钕和铁含量的不同,所得产物的微观结构变化很大,当体系中钕含量由100％→0时,产物的顺-1,4结构含量由94.4％→22.1％,而3,4结构含量由5.6％→77.9％。Al/M(N=Nd+Fe)比、单体浓度和聚合温度不仅对聚合活性有影响,对产物的微观结构影响也较大。事实表明,该聚合体系中存在着两种过渡金属(Nd和Fe)活性中心,它们按各自的机理进行异戊二烯的聚合。     

稀土Eu3+对不同光强下红叶石楠色素含量及PAL活性的影响

以盆栽红叶石楠(Photinia fraseri)优良品种'红罗宾'二年生组培苗植株为供试材料,探讨了不同遮光条件及稀土元素Eu3+处理对其顶部叶片色素含量、苯丙氨酸解氨酶(PAL)活性和Ca2+-ATPase酶活性的影响.结果显示,减少光照强度会导致叶绿素和类胡萝卜素含量上升,而使花青苷、红色素和PAL活性下降;稀土元素Eu3+处理一定程度提高了花青苷含量和PAL及Ca2+-ATPase酶活性.通过Eu3+和钙离子螯合剂(EGTA)、钙离子载体(A23187)、钙通道阻断剂(Verapamil)及钙调蛋白拮抗剂(CPZ)组合处理对50%光强下红叶石楠顶部叶片PAL活性影响的研究,推测Eu3+的生理作用机制可能是Eu3+通过细胞膜上的钙离子转运系统进入细胞内部,取代Ca2+-CaM信号系统中的Ca2+形成Eu3+ -CaM和(或)Eu3+-Ca2+-CaM复合物,替代Ca2+启动钙信号系统激活靶酶,调节效应酶功能,进而调控植物的一系列生理生化过程.     

稀土-其它过渡金属催化剂用于共轭双烯烃的聚合I.(NdCl3+FeCl3).nphen-AlH(i-Bu)2体系对丁二烯的聚合

用共沉淀法制备了不同钕、铁含量的NdCl_3和FeCl_3邻菲罗啉(phen)络合物,并与AlH(i-Bu)_2组成Ziegler-Natta型催化剂,发现这种混合催化剂在合适的Fe/Nd比范围内,对丁二烯的聚合活性高于单一稀土或铁催化剂,尤其是产物的微观结构,可随催化剂中铁、钕含量不同而有较大幅度的变化(cis-1,4含量98—40%,1,2含量1—49%左右,考察了AI/M(M=Nd+Fe的摩尔数)和溶剂对聚合活性的影响,随Al/M的变化,催化剂的活性出现一个高峰;并随催化剂用量不同,活性高峰处的Al/M值也不同,溶剂对催化利活性的影响也很大,其顺序是:甲苯≈苯>环已烷>正己烷,即芳烃>脂环烃>直链烃。     

稀土-其它过渡金属混合催化剂用于共轭双烯烃的聚合——Ⅳ.(NdCl3+FeCl3)·nphen-HAI(i-Bu)2体系对异戊二烯的聚合

 本文报道由(NdCl₃+FeCl₃)·nphen-HAl(i-Bu)₂催化体系引发异戊二烯聚合的结果。在适当Nd/Pe比下,该体系对异戊二烯聚合的活性可超过单一钕或铁催化剂的活性,同时随催化剂中钕和铁含量的不同,所得产物的微观结构变化很大,当体系中钕含量由100％→0时,产物的顺-1,4结构含量由94.4％→22.1％,而3,4结构含量由5.6％→77.9％。Al/M(N=Nd+Fe)比、单体浓度和聚合温度不仅对聚合活性有影响,对产物的微观结构影响也较大。事实表明,该聚合体系中存在着两种过渡金属(Nd和Fe)活性中心,它们按各自的机理进行异戊二烯的聚合。     

钕对缺钙油菜膜损伤和过氧化进程的影响

通过在缺钙条件下对油菜进行水培 ,探讨了Nd对缺钙油菜膜损伤和过氧化进程的影响。3 μmol·L- 1硝酸钕可降低根质膜相对透性和叶片中膜脂过氧化作用产物丙二醛含量 ,提高过氧化氢酶 ,过氧化物酶和超氧化物歧化酶的活性。Nd可减轻油菜缺Ca症状 ,抑制膜的过氧化进程 ,完全营养液中加入硝酸钕也有类似效果。     

镧对美洲商陆毛状根生长、皂苷产生及抗氧化酶活性的影响

采用不同浓度镧来固体培养美洲商陆毛状根,并采用分光光度法来测定毛状根的商陆皂苷含量、抗氧化酶SOD和POD活性及苯丙氨酸裂解酶(PAL)酶活性,以探讨镧对美洲商陆毛状根生长及其次生代谢影响的生理机制。结果表明,镧浓度低于10.0 mg·L~(-1)可促进毛状根的生长,其中以5.0 mg·L~(-1)镧处理的毛状根生物量最大,而高于20.0 mg·L~(-1)镧则抑制毛状根生长,但其皂苷含量最高;与对照相比,低于10.0 mg·L~(-1)镧可提高毛状根SOD活性,其中以1.0 mg·L~(-1)镧的SOD活性最高;而镧浓度为0.5 mg·L~(-1)时,毛状根的POD活性最高,大于0.5 mg·L~(-1)时,POD活性随着镧浓度的升高而降低;而毛状根PAL活性及其皂苷含量则随着镧浓度增大而逐渐提高。表明镧可能通过提高毛状根的抗氧化酶和PAL活性而影响其生长和皂苷的合成。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.