4-羟基香豆素及其衍生物的简便合成及其荧光性质的研究

用米氏酸和苯酚在无溶剂条件下以90.6%的收率合成丙二酸单苯基酯, 然后用Eaton试剂(五氧化二磷＋甲基磺酸)在温和条件下闭环, 以78.8%的收率得到4-羟基香豆素, 将这种方法扩展合成了苯环上带有各种取代基的4-羟基香豆素衍生物以及4-羟基硫代香豆素衍生物. 并对部分4-羟基香豆素衍生物的荧光性质进行了研究.     

8-羟甲基香豆素衍生物的合成

由六种5-取代-3-羟甲基-2-羟基苯甲醛(2～7)分别与乙酰乙酸乙酯和丙二酸二乙酯缩合,得到12种8-羟甲基香豆素衍生物。     

L-脯氨酸催化的香豆素-3-羧酸的“一锅法”合成

用二甲亚砜为溶剂,L-脯氨酸为催化剂,能简便高效地催化水杨醛与丙二酸二乙酯发生Knoevenagel缩合反应得到香豆素-3-羧酸乙酯,之后加入氢氧化钾进行水解,浓盐酸酸化得到香豆素-3-羧酸。本方法具有易于操作,反应收率较高,后处理方便,反应时间短,催化剂和溶剂廉价易得,绿色环保等优点。     

4-芳基香豆素类化合物的合成及体外降糖活性研究

以苯乙酮类化合物和碳酸二乙酯为原料合成了3个含有甲氧基的苯甲酰乙酸乙酯类化合物,在70%的浓硫酸催化下与取代的苯酚类化合物反应生成具有甲氧基的4-芳基香豆素4a-4d,在新制的碘化铝的催化下脱甲基,合成了4个含有多羟基的化合物5a-5d.所有目标化合物均经过IR、1H NMR、ESI-MS对其进行了结构确认.通过测定α-葡萄糖苷酶抑制活性和AGEs形成自由基活性来评价其体外降糖活性.     

PEG-400介质中L-脯氨酸催化香豆素-3-羧酸乙酯的合成

用PEG-400为溶剂,L-脯氨酸作为催化剂,能高效简便地催化水杨醛与丙二酸二乙酯通过Knoevenagel缩合反应得到香豆素3-羧酸乙酯.本方法具有易于操作,后处理方便,反应时间较短,反应收率较高,催化剂和溶剂价廉易得,而且环境友好等优点.     

7-羟基-香豆素-3-羧酸衍生物的合成及抗肿瘤活性

以2,4-二羟基苯甲醛和丙二酸二乙酯为起始原料,经Knoevenagel反应得到7-羟基-香豆素-3-羧酸乙酯(2);再经曼尼希反应、酯水解、酸化,得到7-羟基-8-氨甲基-香豆素-3羧酸(4a～4e);利用其羧基与不同碳数的二溴烷烃反应得到相应的溴代酯(5a～5i),再与硝酸银反应得到9个有机硝酸酯类一氧化氮(NO)供体型7-羟基-香豆素-3羧酸衍生物(6a～6i)。目标化合物的结构经过核磁共振氢谱、碳谱和高分辨质谱确证。用MTT法评价了目标化合物对人肝癌HepG2细胞和人肺癌A549细胞增殖的影响,结果显示,所合成的目标化合物对受试的两种癌细胞均具有较强的增殖抑制作用,其中,化合物6c的活性最好。     

奥拉西坦衍生物的设计、合成及抗血小板聚集活性研究

本文采用拼合策略,设计、合成了7个新型奥拉西坦衍生物。其中,化合物4a～4f由奥拉西坦与苯丙烯酸片段拼合得到; 4g则由奥拉西坦、吲哚布芬拼合得到。采用Bron比浊法测定目标化合物对花生四烯酸及二磷酸腺苷诱导的血小板聚集的抑制活性。结果表明,该系列化合物具有一定的抗血小板聚集活性,其中化合物4f的抗血小板聚集活性与阳性对照吲哚布芬相当。     

微波辅助“一锅煮”合成香豆素3-羧酸类化合物

以取代水杨醛和丙二酸二乙酯为原料,乙醇为溶剂,以吡咯为碱于140 ℃微波反应20 min,再加入氢氧化钠于120 ℃微波反应10 min,采用“一锅煮”的方法合成了8个香豆素-3-羧酸类化合物,收率可达84.0%~96.6%。本方法具有反应时间短、产率高、操作简便的优点,为香豆素-3-羧酸类化合物提供了一种高效、便捷的实验室合成方法。     

香豆素衍生物荧光探针研究进展

对近5年来设计合成的新型香豆素荧光探针研究进展进行综述。系统阐述合成新型香豆素荧光探针在生物学领域的应用,主要包括检测内源性物质、监测细胞结构形态、对重金属离子的定性定量分析等。香豆素母核的活性位点多样,适于结构修饰,基于香豆素荧光探针对7、8位的活性位点进行改造,得到一系列新型香豆素衍生物荧光探针。通过对此类荧光传感器相关技术进展进行综述,为寻找新的荧光结合位点以及合成新型香豆素衍生物传感器提供参考。     

超声辐射在有机合成实验中的应用

超声辐射下,水杨醛和丙二酸二乙酯在六氢吡啶催化下于25℃左右反应0.5 h,以74%~84%的产率得到香豆素-3-甲酸乙酯。与传统方法相比,具有反应时间短、产率高、物耗低及污染少等特点,是一个适合于本科生的超声化学实验。     

Polyhydrazides. II. N-methylated polyhydrazides by direct solution polycondensations of methylated hydrazines and dicarboxylic acid components

N-Methylated polyhydrazides were prepared from methylated hydrazines and terephthalic acid or dimethyl terephthalate, and from terephthalic acid, hydrazine sulfate, and dimethyl sulfate by the solution polycondensation method in fuming sulfuric acid or polyphosphoric acid.     

苯酚和草酸二甲酯在不同分子筛催化下的酯交换反应

研究了以TS－1、H－ZSM－5、Hβ和H－丝光沸石等不同分子筛为催化剂，苯酚和草酸二甲酯酯交换合成草酸二苯酯反应。通过对催化剂进行吸附吡啶的红外光谱和NH3－TPD表征，考察了不同分子筛催化剂的酸性和酸强度对草酸二苯酯合成反应的影响，确定了催化剂上的弱酸中心是催化苯酚和草酸二甲酯酯交换合成草酸二苯酯反应的活性位，且催化剂的酸性中心越多，酸量越大，催化活性越好。催化剂上的强酸中心促进了副产物苯甲醚的生成。     

Occupational exposure to low levels of organic and inorganic substances in a chemical plant for the production of terephtalic acid dimethyl ester

The aim of our study was the evaluation of personal exposure to chemical pollutants in workers employed in a plant for the production of terephtalic acid dimethyl ester. Chemical agents have been included in the monitoring program on the basis of the industrial process. In the plant, the oxidation of p-xylene is performed by air and the resulting acid is esterified with methyl alcohol. Purified terephtalic acid dimethyl ester is then utilized for the production of polyethylene terephtalate. The environmental monitoring included terephtalic acid dimethyl ester, p-toluic acid methyl ester, terephtalic acid, p-xylene, methylacetate, methylbenzoate, formic acid, acetic acid, methanol, and the catalysts cobalt acetate and manganese (II) acetate tetrahydrate. Personal exposure to the cited airborne substances was performed in the breathing zone of six workers. Air samplings were carried out by drawing air through glass fibre filters (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid aerosols), by active adsorption (methanol, formic and acetic acids vapours). p-Xylene, methylacetate and methylbenzoate vapours were collected by passive sampling. Cellulose nitrate filters were used for cobalt and manganese salts samplings. Analyses were performed by UV detection high-performance liquid chromatography (terephtalic acid dimethyl ester, p-toluic acid methyl ester and terephtalic acid), flame ionization detection gas chromatography (p-xylene, acetic acid methyl ester and benzoic acid methyl ester), ion chromatography (formic and acetic acids) and inductively coupled plasma-mass spectrometry (cobalt and manganese). The results were evaluated according to the threshold limit values (TLVs) of the American Conference of Governmental Industrial Hygienists (ACGIH) and indicated that the environmental levels of the workplace pollutants were well below the threshold limit values-time weighed average (TLV-TWA) adopted by the American Conference of Governmental Industrial Hygienists for 2002, although for three substances the TLVs were not available.     

Acid-base titrations in nonaqueous solvents Analysis of dimethyl sulphate

A nonaqueous titrimetric procedure was developed for the determination of the dimethyl sulphate, methyl hydrogen sulphate and sulphuric acid content of dimethyl sulphate samples. Methyl hydrogen sulphate and sulphuric acid are determined by a differentiating potentiometric titration in pyridine with tributylethylammonium hydroxide. Pyridine converts the dimethyl sulphate into the weakly acidic methylpyridinium methyl sulphate which does not interfere in the titration. Dimethyl sulphate is determined by reacting it with an excess of 2-dimethylaminoethanol and titrating the excess with perchloric acid. Precision and recovery data for commercial samples of dimethyl sulphate are presented.     

Quantitative analysis of fatty acid methyl esters and dimethyl acetals on a polar (free fatty acid phase) capillary column

Separation of fatty acid methyl esters and dimethyl acetals from complex biological samples has been achieved by gas-liquid chromatography on a capillary column coated with free fatty acid phase. Response-correcting factors were determined, showing rather large variations with fatty acid length. Polyunsaturated fatty acid methyl esters were shown to have lower responses than saturated species, whereas dimethyl acetals and equivalent methyl esters were found to give similar responses. Total fatty acid and aldehyde compositions of human and simian erythrocytes were determined and compared, showing a somewhat higher level of linoleate and arachidonate, and a lower level of plasmalogens in simian erythrocytes.     

The use of sulfamic acid as a primary standard in nonaqueous titrimetry

A method has been developed for the standardization of a typical nonaqueous base lithium methoxide, with an inorganic primary standard, sulfamic acid. 'T'his acid was found to dissolve readily in four independant basic solvents, dimethyl formamide, ethylenediamine, n-butylamine and dimethyl sulfoxide. Sulfamic acid could be titrated in each of these solvents, by both visual and potentiometric means with lithium methoxide dissolved in benzene-methanol. No gels nor precipitates resulted in the course of the titrations and the accuracy of the method was comparable to that obtained using benzoic acid as the primary standard. Conductometric titrations were also performed using sulfamic acid dissolved in two systems, dimethyl formamide and glacial acetic acid. In the latter solvent it was possible to titrate sulfamic acid with perchloric acid in glacial acetic acid.     

二氯菊酸类杀虫剂光学纯度分析方法的研究

报道了旋光性的顺式－2，2－二甲基－3－（2，2－二氯乙烯基）环丙烷羧酸（谷称顺式二氯菊酸）类杀虫剂光学纯度的色谱分析方法。光学活性杀虫剂的顺式－2，2－二甲基－3－（2，2－二氯乙烯基）环丙烷羧酸先与氯化亚砜生成酰氯，一财与S（－）－a-甲基苄胺作用，生成顺式－2，2－二氯－3－异丁烯基环丙烷羧酸非对映异构体的酰胺，经薄层色谱纯，用高效液相色谱进行分析，即可确定中间体的光学纯度。光学纯度一定的中间体经合成至最终产物，其光学纯度保持不变。     

衍生于手性双二茂铁乙胺的单齿亚磷酰胺配体在不对称催化氢化中的应用

研究了衍生于手性双二茂铁乙胺的手性单齿亚磷酰胺配体的铑络合物催化剂在烯酰胺、β-脱氢氨基酸酯、衣康酸酯以及α-脱氢氨基酸酯的不对称氢化中的应用,结果显示该催化剂具有较好的催化性能,对烯酰胺类底物最高获得了96%的ee值,对β-脱氢氨基酸酯类底物最高获得了86%的ee值,对衣康酸酯最高获得了75%的ee值,对α-脱氢氨基酸酯类底物最高获得了95%的ee值.     

Sulfamic Acid–Catalyzed One‐Pot Synthesis of 3‐(4,6‐Dimethyl‐oxazolo[4,5‐c]quinolin‐2‐yl)‐chromen‐2‐ones using the Conventional Method and Microwave Irradiation

A rapid and efficient method for the preparation of 3‐(4,6‐dimethyl‐oxazolo[4,5‐c]quinolin‐2‐yl)‐chromen‐2‐ones by the reaction between 3‐amino‐2,8‐dimethyl‐quinolin‐4‐ol and 2‐oxo‐2H‐chromen‐3‐carboxylic acid using sulfamic acid as a acid catalyst and dimethyl formamide as a solvent using the conventional method and microwave irradiation is reported.     

Activity of catalysts in the synthesis of dimethyl sulfide from dimethyl disulfide

Dimethyl disulfide conversion at T = 190–350°C over catalysts containing acid and basic sites is reported. The products of this reaction are dimethyl sulfide, methanethiol, hydrogen sulfide, carbon disulfide, methane, and ethylene. At 190°C, these products form via parallel reactions. At higher temperature of up to 350°C, dimethyl sulfide can form by the condensation of the resulting methanethiol. The strong basic sites of the catalysts are uninvolved in dimethyl sulfide formation. Over catalysts whose surface has only strong protonic or strong Lewis acid sites, dimethyl sulfide formation does take place, but slowly and nonselectively. The highest dimethyl sulfide formation activity and selectivity are shown by catalysts having medium-strength basic sites along with strong protonic and strong Lewis acid sites.