吡喃二酮衍生物的活性及吡喃酮并吡唑的合成研究进展

吡喃二酮衍生物具有较好的生物活性。回顾了近年来2,4 吡喃二酮化合物的生物活性的相关报道,概述了该类化合物的研究进展,简要介绍了吡喃酮并吡唑的合成方法。     

乙基麦芽酚的合成工艺研究

乙基麦芽酚的合成工艺研究周建纯朱庆安（珠海金珠应用化学研究所５１９０１５）一、前言乙基麦芽酚学名为２—乙基－３－羟基－４Ｈ－吡喃酮－［４］，英文名称为２－ｅｔｈｙｌ－３－ｈｙｄｒｏｘｙ－４ｈ－ｐｙｒａｎ－４－ｏｎｅ，分子式Ｃ７Ｈ８Ｏ３，分子量１４０．...     

邻(对)羟基苯乙烯酮的合成

介绍了邻（对）羟基苯乙烯酮的制备方法。该法采用丙酮和邻（对）羟基苯甲醛在稀碱存在下，于20℃-25℃进行醛酮缩合反应，合成工艺简单，收率高。用^1HNMR,^13CNMR分析，产品纯度高。     

2,4-吡喃二酮衍生物的合成方法研究进展

2,4-吡喃二酮在医药和农药方面都是一个具有潜在生物活性的母体结构。其衍生物在医药方面具有抗菌、抗癌,抑制HIV朊酶等生物活性,在农药方面具有杀虫、杀菌、除草和抗植物病毒等。介绍了近年来2,4-吡喃二酮衍生物的合成方法的研究进展。     

异黄烷酮化合物的合成研究进展

对近20年异黄烷酮化合物的合成研究进展进行了综述。     

羟基自由基对沸石分子筛合成影响的研究

使用过硫酸钠作为助剂,其水溶液在一定温度下热解产生羟基自由基,与未加入过硫酸钠的分子筛反应液空白实验对照。使用电子顺磁共振(EPR)表征了过硫酸钠溶液中的羟基自由基,使用X射线衍射(XRD)和扫描电子显微镜(SEM)表征了不同晶化时间的产物。结果表明,两组实验在80℃条件下晶化相同时间,未加入过硫酸盐的实验,沸石分子筛产物先生成NaA沸石,而后逐渐转变为方钠石;加入过硫酸钠盐后,产物前期主相即是方钠石,仅产生痕量的NaA沸石,随后很快生成纯的方钠石。羟基自由基可以提高沸石分子筛合成过程中的相选择性和合成效率。     

α—羟基异丙基苯甲酮及其衍生物的合成

研究了α－羟基异丙基苯甲酮及其衍生物的合成工艺，对各单元反应的条件及影响因素等进行了探讨。     

2,3,4-三羟基二苯酮的新合成工艺

以焦性没食子酸为原料,甲醇-水为混合溶剂,草酸-磷酸为催化剂,氮气保护的条件下与三氯甲苯反应,合成了重要的工业材料2,3,4-三羟基二苯酮（3HBP）,反应条件温和。通过单因素实验确定了合成3HBP的最适宜工艺条件为：焦性没食子酸的质量为6.3 g（0.05 mol）,混合溶剂甲醇-水（体积比为2：8）为50.0 mL,升温至40℃时缓慢滴加三氯甲苯（0.055 mol）,滴加完毕后升温至65℃恒温反应至原料焦性没食子酸消失。在最适宜条件合成的3HBP,经柱层析后收率为89.1%。该合成方法简便,环境污染小,绿色环保,具有工业化应用的潜力。     

含环己烯结构新型氯代双酮化合物的合成及表征

本文以顺丁烯二酸酐、氯苯经Ｆｒｉｅｄｌｌｅ－Ｃｒａｆｔｓ反应合成了１,２－二（４－氯苯甲酰基）乙烯。经Ｄｉｅｌｓ－Ａｌｄｅｒ反应,以异戊二烯环加成合成了含环乙烯结构的双氯双酮化合物：１－甲基－４,５－二（４－氯苯甲酰基）环己烯。该氯代双酮化合物具有不饱和双键结构,是制备聚芳醚酮功能高分子材料的理想单体。     

三白草提取物对自由基的清除作用研究

考察了三白草乙醇提取物经不同溶剂萃取所得的各部分对1,1-二苯基-2-三硝基苯肼(DPPH)自由基、羟基自由基和超氧自由基的清除能力。以2,6-二叔丁基-4-甲基苯酚(BHT)为参考。结果表明,三白草乙醇提取物经不同溶剂萃取所得的各部分对DPPH自由基、羟基自由基和超氧自由基都具有清除能力,且随着提取物浓度的增加,清除能力逐渐增高;其中乙酸乙酯部分对DPPH自由基、羟基自由基和超氧自由基的清除作用最强。     

新型分子内复合抗氧剂清除自由基的性能

以DPPH?为研究对象,采用紫外-可见光分光光度计研究了新型分子内复合抗氧剂对自由基的清除能力,并与市售抗氧剂1076和BHT进行对比。结果表明,相同条件下,该新型分子内复合抗氧剂清除自由基的能力优于市售抗氧剂1076和BHT;且清除自由基的能力随抗氧剂浓度的增加而增大,随清除反应时间的延长先增大后趋于稳定。清除反应温度对清除能力影响不大,表明该清除反应的反应活化能较低,该清除反应可在室温下快速进行。熔体流变速率和氧化诱导期测得的结果也证实了新型分子内复合抗氧剂的抗氧化能力优于市售抗氧剂BHT和1076。     

三种黄酮清除自由基活性的研究

为比较黄酮2、3位单双键不同及3'、4'邻位取代基不同对清除自由基活性的影响。采用UV-Vis光谱法测定了木犀草素、香叶木素及橙皮素对1,1-二苯基-2-三硝基苯肼自由基(DPPH·)、超氧阴离子自由基(O2-·)的清除作用。结果显示3种黄酮化合物对两种自由基都有一定的清除作用,清除效果随浓度的增大而增大。但对自由基清除能力表现为木犀草素远强于香叶木素、香叶木素与橙皮素无显著差别。说明具有B环3'、4'邻二羟基结构的黄酮清除自由基的能力明显强于具有B环3'羟基、4'甲氧基结构的黄酮;黄酮C环2、3位单双键不同对自由基清除能力影响不显著。     

Effects of repeated frying on physicochemical characteristics,oxidative stress,and free radical scavenging potential of canola oil and ghee

The repeated use of cooking oils and ghee for the deep frying of food materials may affect their nutritional quality. The present study evaluated the effect of repeated frying on the physicochemical characteristics and antiradical potential of canola oil and ghee. The oil and ghee were used for frying of fish and chicken for 2, 4, 6, 8, and 10 frying cycles followed by the analysis of physicochemical, oxidative stress, and antiradical parameters. Regression analysis of the data showed a frying cycle-dependent significant linear increase in saponification (R² = 0.9507–0.9748), peroxide and acid values (R² = 0.956–0.9915), and malondialdehyde (MDA) production (R² = 0.9058–0.9557) of canola oil and ghee subjected to fish and chicken frying but exponential increase in saponification value (R² = 0.9778) and MDA production (R² = 0.7407) of canola oil and ghee used for fish frying. The increase in the number of frying cycles linearly decreased the iodine value (R² = 0.9781–0.9924), and 1, 1-diphenyl-2-picrylhydrazyl, hydroxyl, and 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging potential (R² = 0.9089–0.9979) of canola oil and ghee. Repeated frying in cooking oil and ghee increases oxidative stress and decreases their physicochemical and antioxidant qualities. Canola oil was comparatively more oxidative resistant than canola ghee. The regression equations derived from regression analysis will guide researchers to conduct similar types of univariate studies.     

Synthesis of polymeric nanofiber and polymeric nanosphere by living free radical polymerization

Living free radical polymerizations are employed to synthesize the polystyrene copolymer. The applications of those copolymer in nanomaterials are elucidated in this research. It involves the copolymerization of styrene with 2‐hydroxyethyl methacrylate. The copolymers are reacted with cinnamoyl chloride, and then irradiated with UV light. The polymeric nanofibers are formed by solvent splitting. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3550–3558, 2006     

Synthesis of macroporous polymers with radical scavenging properties by immobilization of polyphenolic compounds

Solid phase radical scavengers have been prepared by the immobilization of antioxidant (AOX) compounds on macroporous polymers. Poly(glycidylmethacrylate-co-trimethylolpropane trimethacrylate) [poly(GMA–TRIM)] and poly(N-acryloyl-tris(hydroxymethyl)aminomethane-co-glycidylmethacrylate-co-N,N′-methylenebisacrylamide) [poly(NAT–GMA–BIS)] were prepared by free radical polymerization using a mixture of dimethylsulfoxide (DMSO)-poly(ethyleneglycol) 6000 (PEG 6000) as a porogenic solvent. The polymers were aminated with ethylenediamine (EDA) and the linkage of the polyphenolic compounds (gallic and caffeic acids) was carried out by two different approaches: through N,N′-dicyclohexylcarbodiimide/4-dimethylaminepyridine (DCC/DMAP) system (one-step method) or through the previous formation of the acyl chloride of the polyphenolic compounds and subsequent amidation reaction (two-step method). The available phenolic groups on the macroporous polymers were determined using the Folin–Ciocalteu method; the radical scavenging properties of the materials prepared were evaluated using the radical species 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid] radical cation (ABTS⁺). From the results, higher antiradical capacities were obtained with the polymers in which the immobilization of the antioxidant molecules was performed through the two-step method. The polymeric networks prepared in this work yielded up to 13.2 μmol AOX/g of dry polymer, which allowed a quantitative removal of the radicals tested in less than 30 min.     

Synthesis of thermosensitive gel by living free radical polymerization mediated by an alkoxyamine inimer

Thermosensitive gel is synthesized through controlled/“living” free radical copolymerization of styrene and DVB mediated by an alkoxyamine inimer, 2,2,6,6-tetramethyl-1-(1′-phenylethoxy)-4-(4′-vinylbenzyloxy)-piperidine (V-ET). The inimer plays the role of both incorporating “T-shaped” inter-chain linkages and mediating the polymerization. First order kinetics is observed for crosslinking polymerizations before gel point, indicating a constant concentration of propagating radicals. Monomer conversion at the gel point depends on the feed ratio of DVB to V-ET. Higher amount of V-ET results in later gel point due to smaller molecular weight of the primary chains that depends inversely on the concentration of nitroxide. The resulting gel contains permanent and labile crosslinking points formed by DVB units and alkoxyamine moieties, respectively. Therefore, the gels exhibit gel-sol transition within a narrow temperature range. The gel properties, such as the swelling ratio and gel-sol transition temperature, can be controlled by changing the feed ratio of DVB to V-ET. The microenvironments in different gels, or at different temperatures, are investigated by ESR spectroscopy.     

Free radical scavenging activity of cellulase‐treated chitosan

Partially N‐acetylated chitosan was hydrolyzed by the cheap, commercially available, and efficient cellulase. The products, with different molecular weight, were comparatively investigated by GPC, FT‐IR, XRD, and NMR. The results show that the decrease of molecular weight led to transformation of crystal structure and increase of water‐solubility, but the chemical structures of residues were not modified. Superoxide anion radical and hydroxyl radical quenching assay were used for the evaluation of free radical scavenging activity of cellulase‐treated chitosan in vitro. Low molecular weight chitosan (LMWC3, M_w 1.7 × 10³) exhibited high scavenging activity against free radical. It scavenged 79.3% superoxide radical at 0.1 mg mL^?1. At 2.0 mg mL^?1, scavenging percentage of initial chitiosan, LMWC1 (M_w 27.3 × 10³), LMWC2 (M_w 5.9 × 10³), and LMWC3 (M_w 1.7 × 10³) against hydroxyl radical was 14.3%, 33.1%, 47.4%, and 65.9%, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Synthesis of amphiphilic block copolymer of acrylamide with styrene using free radical interfacial copolymerization

A novel free radical interfacial copolymerization was proposed and used to prepare the amphiphilic block copolymer of acrylamide (AM) with styrene (S). In this copolymerization, a synthesized new kind of initiator, namely, amphiphilic bifunctional initiator, which has not only a hydrophilic and a hydrophobic group but also two functional groups generating radicals in both ends of its molecule, was used to initiate the interfacial copolymerization. The generated amphiphilic block copolymer was characterized by infrared analysis, differential scanning calorimetry, elemental analysis, and dissolution behavior. The migration of generated copolymer from interface to water phase was discussed. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 443–449, 1998     

自由基酰化反应合成4-氯-2,6-二酰基吡啶

由4-氯吡啶通过自由基酰化反应合成4-氯-2,6-二乙酰基吡啶和4-氯-2,6-二丙酰基吡啶,方法简单,产率较文献方法高,分别达到25.7%和51.7%。