磺酸功能化离子液体催化3-羟基丙酸甲酯酯交换聚合反应

以磺酸功能化咪唑离子液体为催化剂,以3-羟基丙酸甲酯为原料,采用自身酯交换法合成了具有生物可降解性能的聚羟基脂肪酸酯.系统考察了离子液体种类、反应温度以及聚合反应时间对反应性能的影响,同时采用红外、核磁、热分析等手段对产物进行表征.研究结果表明:阴离子为CF3SO-3的磺酸功能化离子液体在120℃的低温下催化聚合反应所得聚酯Mw可达10 159,收率82.1%;通过水洗方法可有效去除产物中的离子液体催化剂,从而避免催化剂污染产物.     

酸性咪唑类离子液体催化合成2-氯丙酸乙酯

研究了酸性咪唑类离子液体中2-氯丙酸乙醇的合成.制备了4种咪唑类离子液体作为催化剂用于酯化反应,通过Hammett方法测定其酸度,讨论了酸度-催化活性之间的关系.实验发现[Hmim] HSO4拥有比其它几种离子液体更好的催化效果.考察了离子液体用量、反应物配比、反应时间和反应温度对反应结果的影响.得到较佳的反应条件:n...     

β-(3,4-二羟基苯基)-α-羟基丙酸异丙酯/冰片酯合成研究

以3,4-二羟基苯甲醛为起始原料, 经苄基保护、Darzens环氧化、Lewis酸开环、NaBH4还原、催化加氢脱保护得到β-(3,4-二羟基苯基)-α-羟基丙酸异丙酯和β-(3,4-二羟基苯基)-α-羟基丙酸冰片酯, 所得化合物的结构通过1H NMR、13C NMR, IR, MS证实. 该方法操作简单、毒性低、产物易于纯化.     

(S)-2-乙氧基-3-(4-羟基苯基)丙酸乙酯的合成

(S)-2-乙氧基-3-(4-羟基苯基)丙酸乙酯的合成;二乙氧基乙酸乙酯;Horner Wadswordth Emmons反应;催化氢化;化学拆分;（S） 乙氧基（羟基苯基）     

3-羟基-1-金刚烷甲基乙烯基醚的合成

以3-羟基-1-金刚烷甲醇和乙炔为原料,庚烷为溶剂,叔丁醇钾为催化剂,氧化锌为助催化剂,于140℃/1.0 MPa反应3.0 h合成了3-羟基-1-金刚烷甲基乙烯基醚,收率85%,纯度≥99.5%,其结构经IR确证。     

氨基-3-氰基丙酸衍生物的合成

以廉价易得的2,5-二溴吡啶为原料,经取代、氧化、R-(+)-叔丁基亚磺酰胺手性诱导、氨基化、氨基酸缩合等反应,合成了氨基-3-氰基丙酸衍生物,其结构经¹H-NMR, ¹³C-NMR和LC-MS确证。同时对吡啶环5位取代反应机理进行探讨,并且采用ELISA法研究了氨基-3-氰基丙酸衍生物对炎症细胞（BMDM）Caspase-1活性的影响。结果表明：经11步合成的氨基-3-氰基丙酸衍生物结构新颖,并且对Caspase-1的抑制活性具有剂量依赖性。      

3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的合成

报道了以草酸二乙酯为原料,制备具有焦糖香味的香料化合物3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮的方法:首先乙基溴化镁与草酸二乙酯通过格氏反应,以约50%产率生成2-氧代丁酸乙酯,然后其在碳酸钾的作用下发生缩合反应,以约94%产率得到3-羟基-4-甲基-5-乙基-5-乙氧羰基-2(5H)-呋喃酮,再通过水解、脱羧反应,得到3-羟基-4-甲基-5-乙基-2(5H)-呋喃酮.路线总收率约36%.     

3-邻氯苯基-3-(5,5二甲基-3-羟基-2-环己烯-1-酮-2-基)丙酸乙酯的合成和晶体结构

标题化合物C19H23O4Cl（4）是由邻氯苯甲醛（1）与5，5-二甲基-1，3-环己二酮（2）、2，2-二甲基-1，3-二氧六环-4，6-二酮（3）在乙醇中反应而得。结构通过单晶X-射线衍射分析确定，其晶体属于单斜晶系，空间群晶体结构用直接法解出，使用全矩阵最小二乘法对原子参数进行修正，最后的偏离因子R＝0．034，Rw＝0．042。在晶体结构中存在一个共轭的烯醇结构。单晶X-射线分析表明；平面1（C（1）～C（6）、Cl）和平面2（C（8）～C（10）、C（12）、C（13））之间的两面角为97．11°，原子C（7）呈变形的四面体构型。     

BF3·Et2O催化Pechmann反应一锅合成3-氨基-5,7-二羟基-4-甲基香豆素

3-氨基-5,7-二羟基-4-甲基香豆素（4）是一种新的重要有机合成中间体,可用于多种潜在生物活性物质的合成。本文将间苯三酚与2-乙酰氨基乙酰乙酸乙酯（2）在BF3.Et2O的催化作用下,经串联的Pechmann缩合反应和脱乙酰基反应一锅合成4。化合物2由乙酰乙酸乙酯经成肟、还原、酰化反应制得。中间体和目标物的结构均经1H NMR、13C NMR、MS表征。该方法具有原料廉价易得、步骤短、操作简便易控、反应条件温和、收率高的优点。     

Preparation of PVA-GA-CS/PVA-Fe-SA bipolar membrane and its application in electro-generation of 2,2-dimethyl-3-hydroxypropionic acid

PVA-GA-CS/PVA-Fe-SA bipolar membrane was prepared by a paste method. PVA-sodium alginate (SA) and PVA-chitosan (CS) were cross-linked by FeCl₃ and glutaraldehyde (GA), respectively. The charge densities of PVA-CS and PVA-SA solutions were determined by the colloid titration. The swelling level of bipolar membrane was in the range of 25–85%, meanwhile the permeability and the ion-exchange capacity as well as co-ion transport properties was investigated. FTIR was applied to analyze the functional groups of the bipolar membrane. Furthermore, SEM photographs of the BPM cross-section illustrated a structure that consists of an anion layer (PVA-GA-CS) and a cation layer (PVA-Fe-SA). TG analysis of PVA-GA-CS/PVA-Fe-SA bipolar membranes exhibited a good thermal stability. PVA-GA-CS/PVA-Fe-SA bipolar membranes were used as the separator in the electrolysis cell for electro-generation of 2,2-dimethyl-3-hydroxypropionic acid. The average current efficiency was 52.2%, and the highest current efficiency reached 68.9%.     

聚(乙烯基四唑-co-丙烯酸)的合成与表征

以聚丙烯腈为原料,首先通过部分腈基的[3+2]合环反应转化为聚(乙烯基四唑-co-丙烯腈)[Poly(VT-co-AN)],再通过碱性水解反应将剩余的腈基转化为羧基,合成出聚(乙烯基四唑-co-丙烯酸)[Poly(VT-co-AA)]。 采用傅里叶红外变换光谱仪(FT-IR)、核磁共振碳谱仪(¹³C NMR)、酸碱滴定等方法对Poly(VT-co-AN)和[Poly(VT-co-AA)的结构进行了表征,结果表明,Poly(VT-co-AN)的分子链中含有腈基、四唑基团和部分羧基,四唑基团的含量为68.6%,与酸碱滴定法测定的四唑基团的含量相近,[Poly(VT-co-AA)中含有四唑基团和羧基,不含有腈基,酸值高于Poly(VT-co-AN),四唑基团的含量为67.6%,与叠氮化钠与聚丙烯腈的摩尔比相近。 热失重分析结果显示[Poly(VT-co-AA)的热分解速率加快,在270~285 ℃的温度区间内分解完全。     

Darzens synthesis of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid derivatives

Esters and amides of 2,2-dichloro-3-(2-furyl)-3-hydroxypropionic acid were prepared by the reaction of furfural with dichloroacetic acid derivatives under the conditions of the Darzens condensation. The structures of the reaction products were confirmed by their¹H NMR and IR spectra and chemical transformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1444–1448, August, 1994.     

Poly(lactic acid) Synthesis in Solution Polymerization

The step-growth polymerization of L-lactic acid in solution was studied in this work. In order to attain a polymer with high molecular weight, the water formed during the polymerization must be continuously removed. The use of organic solvents with high boiling point, drying agents and reduced pressure led to poly(lactic acid) (PLA) with high molecular weight, directly from the monomer. Tin (II) chloride dihydrate, SnCl₂.2H₂O, was the best of the catalysts tested as it allowed achieving PLA with a molecular weight close to 80 000 g.mol⁻¹. However, the stereoregurarity control is a severe problem in PLA synthesis by step-growth due to transesterification reactions, which lead to an inversion of the conformation and a decrease of the optical purity of the polymer. Specific rotation measurements were used in this work and showed to be a powerful technique to evaluate the racemization extent. The thermal stability of the PLA samples was evaluated by DSC which exhibits a thermal behaviour similar to the commercial Polylactide.     

端羟基聚乳酸的合成与表征

采用共沸除水与醇酸缩合反应相结合的方法合成端羟基聚乳酸。通过L9(3^4)正交实验对合成工艺进行了研究,分析了抗氧剂TPP对反应的影响,并用^1H-NMR和DSC对产物结构进行表征。结果表明,产物主要为聚乳酸-1,4-丁二醇(PIA-1,4-BD)。和分子量相同的聚乳酸-1,4-丁二醇．聚乳酸(PLA-1,4-BD-PLA)比较,PLA-1,4-BD具有较高的Tg。     

Synthesis, degradability, and drug releasing properties of methyl esters of fungal poly(beta,L-malic acid)

Methyl esters of microbial poly(beta,L-malic acid) for conversion degrees of 25, 50, 75, and 100% were prepared by treatment of the polyacid with diazomethane. Esterification proceeded with retention of the molecular weight of the parent polyacid and the copolymers displayed a blocky microstructure consisting of short segments of malic and methyl malate sequences. The thermal stability of the copolyesters was lower than those of the parent homopolymers and all of them were fairly crystalline with melting temperatures within the range of 170-175 degrees C. They were degraded rapidly by water, the hydrolysis rate being highly dependent on the methylation degree. Microspheres with mean-average diameters in the range of 1-20 microm were prepared from the 100% methylated product by the emulsion-evaporation solvent method. Encapsulation of erythromycin was efficiently performed in these microparticles and its releasing upon incubation in simulated physiological medium was evaluated for different drug loads. Drug delivery was observed to occur by a releasing mechanism largely determined by the hydrodegradation of the host polymer and independent of the amount of loaded drug.     

Synthesis of hydrolytically degradable aromatic polyesters with lactide moieties

A synthetic route to higher molecular weight processable polyesters with bisphenol A terephthalate/isophthalate moieties and lactide moieties which are of potential interest for tissue engineering is described. The combination of aliphatic and aromatic moieties is a promising concept for processable polyesters with potential sites for physiological degradation and improved mechanical properties. The molecular structure of the copolyesters prepared by melt condensation via an acid chloride route and incorporation of the lactide moieties by transesterification of an oligo dl -lactide was confirmed by infrared, ¹H and ¹³C nuclear magnetic resonance spectroscopy as well as gel permeation chromatography. The thermal and mechanical properties of copolyesters with different amounts of lactide moieties are reported and correlated with their composition. The reaction mechanism by transesterification was proved by a model reaction with a physical blend of the components and the hydrolytical behavior of the copolyesters under physiological conditions has been investigated. © 1997 John Wiley & Sons, Ltd.     

Synthesis and reactivity of 3-(trichlorogermyl)propanoic acid and 3-(triphenylgermyl) propanoic acid

3-(Trichlorogermyl)propanoic acid (la) reacts with phenylmagnesium bromide in malar ratio 1:4 to give 3-(triphenylgermyl)propanoic acid (2a).In the compounds la and 2a theβ-carboxylic functional group shows some unusual properties when they react with excess of phenylmagnesium bromide.The compound la reacts with phenylmagnesium bromide in molar ratio 1:5 to give phenyl 2-(triphenylgermyl)ethylketone (3a) and in molar ratio 1:6 to give l,l-diphenyl-3-(triphenylgermyl)propanol (4a).The compound 2a reacts with phenylmagnesium bromide in molar ratio 1:2 to give 3a and in molar ratio 1:3 to give 4a also.Dehydration of the compound 4a with dilute hydrochloric acid seems especially easy.Moreover,the compound la reacted with phenylmagnsium bromide in molar ratio 1:6,then the mixture was treated with dilute hydrochloric acid to give 1,1-diphenyl-3-(triphenylgermyl)-1-propene (5a) in one pot reaction.Alkyl Ge-C bond in the compound 5a can be cleaved selectively by lithium aluminium hydride ( LiAlH4) in good yiel     

无毒催化剂催化合成外消旋聚乳酸及其在药物缓释微球中的应用

以D，L－乳酸单体为原料，使用人体营养添加剂如乳酸锌、乳酸钙，乙酸锌、硫酸锌、牛磺酸等作为无毒催化剂，通过熔融聚合直接合成低分子量的生物降解材料外消旋聚乳酸（PDLLA），粘均分子量接近4000，以PDLLA为载体，应用于制备抗菌药物环丙沙星聚乳酸微球，用DSC和SEM表征其成球性能，载药微球体外缓释半衰期为31．9h,53.2h后累积释药百分率约为84．0％，具有明显的缓释作用。     

Preparation of Clickable Poly(3‐hydroxyalkanoate) (PHA): Application to Poly(ethylene glycol) (PEG) Graft Copolymers Synthesis

A new synthesis of amphiphilic biodegradable copolymers consisting of hydrophobic poly(3‐hydroxyalkanoate) (PHA) backbone and hydrophilic poly(ethylene glycol) (PEG) units as side chains is described. Poly[(3‐hydroxyoctanoate)‐co‐(3‐hydroxyundecenoate)] (PHOU) was first methanolyzed and its unsaturated side chains were quantitatively oxidized to carboxylic acid. Esterification with propargyl alcohol led to an alkyne‐containing “clickable” PHA in 71% conversion. Its reactivity was successfully demonstrated by grafting azide‐terminated PEG chains of 550 and 5 000 g · mol⁻¹, respectively. All products were fully characterized using GPC, ¹H, and COSY NMR.