超支化分子桥联受阻酚抗氧化剂的合成与表征

以正十八胺为核的1.0代超支化大分子和β-(3,5-二叔丁基-4-羟基苯基)丙酰氯为原料,通过酰胺化缩合反应,合成了一种具有长链烷基和2个受阻酚基团的新型超支化分子桥联受阻酚类抗氧化剂.通过正交实验确定了超支化分子桥联受阻酚类抗氧化剂的最佳合成体系为:3,5-丙酰氯为酰化剂、K_2CO_3为缚酸剂、苯和水为反应溶剂.通过条件优化实验确定了超支化分子桥联受阻酚类抗氧化剂的最佳合成条件为:3,5-丙酰氯与1.0代超支化大分子的物质的量比为6∶1、反应温度为25 ℃、反应时间为12 h、体系苯与水体积比为6∶1、3,5-丙酰氯与缚酸剂K_2CO_3的物质的量比为1∶1,在此条件下,超支化分子桥联受阻酚类抗氧化剂的收率高达75.5%.FT-IR和1H NMR证实了合成抗氧化剂的化学结构与其理论结构相符.超支化分子桥联受阻酚类抗氧化剂在聚乙烯树脂中的抗氧化性能优于抗氧化剂1076,且随着烷基链长度的增加,抗氧化性能增强.     

一类新型受阻酚抗氧剂的合成与表征

以3,5-丙酰氯和1.0代以氨为核的星型聚酰胺-胺为原料,通过缩合反应合成一类结构新颖的受阻酚抗氧剂,通过正交实验确定新型抗氧剂的最佳合成工艺条件为:n(3,5-丙酰氯):n(1.0代PAMAM)=5:1,溶剂三氯甲烷用量为40mL,反应时间为12 h,分段升温.此条件下,产品收率在65％以上,熔点为204.5℃～20...     

树状聚酰胺-胺桥联受阻酚类抗氧化剂的合成及清除DPPH·活性研究

以系列1.0、2.0代树状聚酰胺-胺(PAMAM)为桥联基,3-(3,5-二叔丁基-4-羟基苯基)丙酰氯为抗氧化基团,通过酰胺化缩合反应合成了系列树状桥联受阻酚类抗氧化剂。红外光谱和核磁共振氢谱证实了系列树状聚酰胺-胺桥联受阻酚类抗氧化剂的化学结构。采用EPR技术研究系列树状聚酰胺-胺桥联受阻酚类抗氧化剂清除DPPH·的能力,结果表明,系列树状聚酰胺-胺桥联受阻酚类抗氧化剂具有良好清除DPPH·活性,且随着清除时间的延长、桥联基长度和代数的增加,其清除活性增强。     

脂肪二胺桥联受阻酚的合成及抗氧化活性研究

以脂肪二胺为桥联基,通过与β-(3,5-二叔丁基-4-羟基苯基)丙酰氯酰胺化缩合反应,合成了4种脂肪二胺桥联受阻酚.核磁氢谱和质谱证实了脂肪二胺桥联受阻酚的化学结构,采用DPPH法和测氧法对脂肪二胺桥联受阻酚的抗氧化活性进行了研究.结果表明脂肪二胺桥联受阻酚对含氮自由基DPPH和过氧自由基ROO均具有良好的抗氧化活性.随着受阻酚桥联基的增长,受阻酚清除自由基的活性均下降,但随着受阻酚物质的量分数的增加,清除活性均增大,且桥联基对清除DPPH自由基活性的影响大于清除ROO自由基的活性.     

树状桥联半受阻酚类抗氧剂的合成与抗氧化性能

从端基为胺基树状大分子出发, 合成了一种具有多个半受阻酚抗氧化基团、 结构对称的树状桥联半受阻酚类抗氧剂. 元素分析、 傅里叶变换红外光谱(FTIR)、 氢核磁共振波谱(¹H NMR)、 质谱(MS)和冰点降低法证实合成的树状桥联半受阻酚类抗氧剂的化学结构与理论结构一致, 纯度较高. 采用1,1-二苯基-2-苦基肼(DPPH)法和差热扫描量热(DSC)法研究了树状桥联半受阻酚类抗氧剂的抗氧化性能, 并与相应的树状桥联全受阻酚类抗氧剂进行了对比. 研究结果表明, 树状桥联半受阻酚类抗氧剂清除DPPH自由基的活性不仅与清除体系中抗氧剂的浓度有关, 而且与清除时间有关; 清除时间为30 min时的抗氧化能力是清除时间为400 min时抗氧化能力的近2倍. 树状桥联半受阻酚类抗氧剂的半受阻效应使其在DPPH体系和HDPE树脂中的抗氧化能力均优于其相应的树状桥联全受阻酚类抗氧剂.     

一种树状桥联水杨醛亚胺配体的合成与表征

以甲醇为溶剂,将具有配位能力的水杨醛(2)通过Schiff碱缩合反应接枝到整代聚酰胺-胺(1)骨架上,合成了一种树状桥联水杨醛亚胺配体,其结构经1H NMR,IR和元素分析表征.最佳反应条件为:1 4 mmol,n(1):n(2)=1:6,甲醇30 mL,于65℃反应5 h,产率在90%以上.     

对硝基邻苯二乙醚合成技术研究

以邻苯二酚与溴乙烷为原料、聚乙二醇为相转移催化剂合成邻苯二乙醚,再经过冰醋酸和硝酸硝化得到对硝基邻苯二乙醚。研究了反应温度、反应时间、原料摩尔比和催化剂用量等对反应收率的影响,获得了合成邻苯二乙醚的优化工艺条件:n(C6H4(OH)2)∶n(NaO H)∶n(C2H5Br)=1∶2.6∶2.4,反应温度80℃,反应时间4h,催化剂用量2g,该反应条件下邻苯二乙醚平均收率88%。混酸硝化条件下合成对硝基邻苯二乙醚的较佳工艺条件为n(C10H14O2)∶n(HNO3)=1∶1.2,乙酸25mL,反应时间30min,反应温度20℃,该反应条件下对硝基邻苯二乙醚平均收率为99%。     

聚酰胺-胺树状高分子与稀土离子络合的荧光光谱研究

合成了4.0代聚酰胺-胺(PAMAM)树状分子,用荧光分光光度法研究了4.0代PAMAM树状分子与Sm3 、Dy3 、Ce3 的络合作用.结果表明,反应时间、PAMAM物质的量、反应体系pH都会影响PAMAM对Ce(Ⅲ)、Sm(Ⅲ)及Dy(Ⅲ)离子的配位作用,对端氨基树状高分子主要存在RE-N4和RE-N2两种配位方式;随着稀土离子的加入,各种配位方式的相对比例会发生变化;pH对配位方式也有较大的影响.该研究为制备尺寸可控的PAMAM树状高分子封闭的稀土原子簇提供了理论基础.     

4-(二苯氨基)苯甲醛的合成工艺改进

以Al Cl3为催化剂,三苯氨(1)和原甲酸三乙酯(2)为原料,合成了4-(二苯氨基)苯甲醛(3),其结构经1H NMR和FT-IR确证。合成3的较佳工艺条件为:1 40 mmol,n(1)∶n(2)∶n(Al Cl3)=1∶5∶8,苯为溶剂,于30℃反应4 h,收率91%。     

2,3,6,7,10,11-六甲氧基苯并菲的合成工艺改进

以1,2-二甲氧基苯(1)为原料,二氯乙烷为溶剂,氯化铁为催化剂,合成了2,3,6,7,10,11-六甲氧基苯(2)。在142 mmol,n(FeC l3)∶n(1)=4∶1,50℃反应2 h的最佳反应条件下,2的收率达81.48%。     

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.