碳酸钾催化无溶剂合成3-取代香豆素衍生物

利用K2CO3作催化剂催化水杨醛类化合物与丙二酸二乙酯或乙酰乙酸乙酯(或甲酯),通过Knoevenagel缩合反应快速简便地合成了10种3-取代香豆素衍生物。探讨了三因素对合成香豆素-3-甲酸乙酯产率的影响,结果表明,水杨醛物质的量为20mmol,水杨醛与丙二酸二酯摩尔比为1︰1.2,K2CO3用量为0.1mmol,反应15min～18min,产率可达88.1%;当用乙酰乙酸乙酯(或甲酯)代替丙二酸二乙酯时,得到3-乙酰基香豆素,产率达84.7%(或82.9%);当用固态取代水杨醛代替水杨醛分别与丙二酸二乙酯和乙酰乙酸乙酯(或甲酯)在摩尔比为1︰2.0条件下反应时,得到8种3-取代香豆素衍生物,产率达62.5%~89.0%(或58.1%~83.0%);带供电子基取代水杨醛有利于提高合成产率。     

3-苯甲酰香豆素的合成及对谷氨酸和多肽的检测

以水杨醛和苯甲酰乙酸乙酯为原料,哌啶作催化剂,利用Knoevenagel反应合成了3-苯甲酰基香豆素,为该类化合物的合成提供了一种新的方法。与常规方法相比,利用此反应可以得到较高产率的3-取代香豆素,并且该反应反应条件温和,反应时间较短,产物后处理简单。3-苯甲酰基香豆素可以作为荧光探针对谷氨酸和谷胱甘肽进行检测,研究结果表明,3-苯甲酰基香豆素与谷氨酸和谷胱甘肽作用后,发生了明显的荧光减弱现象和荧光红移现象,这对于识别谷氨酸和谷胱甘肽具有很好的使用价值。     

碳酸钾催化无溶剂合成3-取代香豆素衍生物

利用K2CO3作催化剂催化水杨醛类化合物与丙二酸二乙酯或乙酰乙酸乙酯(或甲酯),通过Knoevenagel缩合反应快速简便地合成了10种3-取代香豆素衍生物。探讨了三因素对合成香豆素-3-甲酸乙酯产率的影响,结果表明,水杨醛为20 mmol,水杨醛与丙二酸二酯摩尔比为1∶1.2,K2CO3用量为0.1 mmol,反应15~18 min,产率可达88.1%;当用乙酰乙酸乙酯(或甲酯)代替丙二酸二乙酯时,得到3-乙酰基香豆素,产率达84.7%(或82.9%);当用固态的取代水杨醛代替水杨醛分别与丙二酸二乙酯和乙酰乙酸乙酯(或甲酯)在摩尔比为1∶2.0条件下反应时,得到8种3-取代香豆素衍生物,产率达62.5%~89.0%(或58.1%~83.0%)。     

香豆素肟酯类化合物的合成

以取代的3-乙酰基香豆素或3-丁酰基香豆素为原料,通过两步法合成了一系列香豆素肟酯类化合物(Ⅲa~k)。以3-乙酰基香豆素肟与乙酸酐的反应为模板反应,考察了溶剂的种类和反应温度对产物Ⅲa产率的影响,结果表明:以四氢呋喃为溶剂、反应温度为60℃时,产物Ⅲa的产率最高(88%)。在最优条件下,以67%~92%的收率得到11种含不同取代基的香豆素肟酯类化合物。对目标化合物的结构进行了红外、核磁、高分辨质谱确证,并对Ⅲa进行了X射线单晶衍射分析。     

离子液体([bmim]Cl)促进下醛基香豆素的Reformatsky反应

在离子液体氯化1-丁基-3-甲基咪唑([bmim]Cl)存在下,Zn粉活化的α-溴代苯乙酮类化合物与6-甲基-4-醛基香豆素发生Reformatsky反应,合成出三种香豆素取代的β-羟基酮类化合物。通过IR和1 H NMR对所合成的化合物进行了结构表征。实验结果表明,离子液体[bmim]Cl能够促进溴代苯乙酮与醛基香豆素的Reformatsky反应,并以较高产率得到香豆素取代的β-羟基酮类化合物。离子液体[bmim]Cl经处理后可循环利用,并且效率较高。     

芳基取代香豆素合成方法的研究进展

本文综述了在香豆素母体环上具有不同取代基的3-位和4-位芳基取代化合物的合成进展。其中Perkin反应以水杨醛和芳基乙酸为原料，在有机碱和醋酸酐存在下反应，而对于有N，N-二乙氨基取代的香豆素则需要用Knoevenagal反应在催化量的有机碱存在下由N，N-二乙氨基取代的水杨醛与芳基乙腈反应制得。由于一些取代水杨醛的合成比较困难，这时可利用Pechmann反应在路易斯酸催化下由取代酚直接反应制备香豆素化合物，以上这三种制备芳基取代香豆素的方法一般收率都较高，可应用于工业化生产，另外，在Vilsmeier-Haack反应中可用Vilsmeier试剂来制备芳基香豆素化合物。该反应副产物反物很少，条件比较温和，利用钯金属等催化合成的4-芳基香豆素化合物反应中，避免了常用的Pechmann反应中使用等当量的矿物酸或路易斯酸。可减少对环境带来的污染。     

3-苯基-7-氨基香豆素和香豆素类型荧光增白剂

3-苯基-7-氨基香豆素是合成3,7-取代香豆素类型荧光增白剂的重要中间体.文章首先介绍了四种合成该中间体的工艺路线,再将该中间体7-位上的氨基缩合环化和取代构成一些含唑基的香豆素类型荧光增白剂和一些含三嗪基的香豆素类荧光增白剂.它们广泛用于纺织印染,塑料加工等的增白.     

3-苯基-7-氨基香豆素和香豆素类型荧光增白剂

3-苯基-7-氨基香豆素是合成3,7-取代香豆素类型荧光增白剂的重要中间体。文章首先介绍了四种合成该中间体的工艺路线,再将该中间体7-位上的氨基缩合环化和取代构成一些含唑基的香豆素类型荧光增白剂和一些含三嗪基的香豆素类荧光增白剂。它们广泛用于纺织印染、塑料加工等的增白。     

几种新的吡唑啉衍生物的合成

以水杨醛、乙酰乙酸乙酯为原料合成3-乙酰基香豆素,3-乙酰基香豆素与各种取代基的苯甲醛反应生成相应的查尔酮,查尔酮再与2-肼基苯并噻唑反应合成了5种未见报道的吡唑啉,并通过核磁氢谱等对吡唑啉进行了表征。并对合成吡唑啉条件中的溶剂的选择以及温度的单因素实验,对合成条件进行了优化。     

3位或4位取代7-羟基香豆素的合成研究

香豆素类化合物是重要的荧光材料,具有苯并吡喃酮环状结构,环上取代基对荧光性质具有重要影响。本文以Pechmann反应和Knoevenagel反应合成了三个3位或4位取代7-羟基香豆素,并优化了反应条件,反应快速,操作简便,产品收率较高。     

Synthesis of novel 3‐hetaryl‐substituted 6‐ and 8‐hydroxybenzo[f]coumarin derivatives

Eight novel 3‐hetaryl‐substituted 6‐ and 8‐hydroxybenzo[f]iminocoumarin compounds were synthesised by the reaction of 2,5‐dihydroxynaphthaldehydes or 2,7‐dihydroxynaphthaldehydes with 2‐cyanomethylbenzo‐thiazole, 2‐cyanomethylbenzoimidazole, 1‐methyl‐2‐cyanomethylbenzoimidazole and 2‐cyanomethyl‐4‐phenylthiazole. The iminocompounds obtained were hydrolysed with hydrochloric acid to the benzo[f]coumarins. Becaue of the high reactivity of the iminocoumarins, only mixtures which also contained the corresponding coumarin compounds were isolated. The absorption and steady‐state fluorescence characteristics of the benzo[f]coumarins (benzo[f]chromen‐2‐ones) synthesised were studied in ethanol and in toluene.     

Solvent free synthesis of coumarin derivative by the use of AlSBA-1 molecular sieves

AlSBA-1 molecular sieves were synthesized successfully and used for the synthesis of coumarins through Pechmann condensation. The synthesized AlSBA-1 catalysts were characterized by XRD, BET, SEM, FTIR, TGA techniques. The synthesized materials possess large surface area with mesopores. Pechmann condensation of 3-methoxyphenol and ethyl acetoacetate was carried out under solvent free condition and 7-methoxy-4-methylcoumarin was the main product. The selectivity of the product was found to be 74.04%. Among the synthesized catalysts, AlSBA-1(2) showed high activity than others due to high density of acid sites. Hence, AlSBA-1 molecular sieves a better choice of catalyst for the synthesis of coumarins.     

Analysis,isolation and insecticidal activity of linear furanocoumarins and other coumarin derivatives fromPeucedanum (Apiaceae: Apioideae)

Peucedanum arenarium Waldst. & Kit.,P. austriacum (Jacq.) Koch,P. coriaceum Reichenb.,P. longifolium Waldst. & Kit,P. officinale L.,P. oreoselinum (L.) Moench,P. ostruthium L., andP. palustre (L.) Moench accumulate different structural types of coumarins including simple coumarins, linear furanocoumarins, linear dihydropyranocoumarins, angular dihydrofuranocoumarins and angular dihydropyranocoumarins. Linear furanocoumarins, known for various biological activities, include some well-known antifeedants, such as bergapten, isopimpinellin, and xanthotoxin. The aim of this investigation was to screen the diverse coumarins fromPeucedanum for insecticidal activity. LC was used to analyze and isolate coumarins for the bioassays. A growth inhibition bioassay with 17 derivatives, comprising all structural types fromPeucedanum, carried out withSpodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae) as test organism, indicated the majority of the linear furanocoumarins and the angular dihydrofuranocoumarin athamantin as active compounds. Oxygenation of the prenyl residue of linear furanocoumarins decreased activity. Further formation of an ester with angelic acid even resulted in complete inactivity. Five active linear furanocoumarins, bergapten, isopimpinellin, xanthotoxin, isoimperatorin, and imperatorin, and two linear furanocoumarins with a substituted furan ring, peucedanin and 8-methoxypeucedanin, were compared in a dietary utilization bioassay. Relative growth rate (RGR) and relative consumption rate (RCR) divided the tested coumarins in three groups of similar activity. Isopimpinellin and peucedanin slightly decreased RGR and RCR of the treated larvae, and xanthotoxin, isoimperatorin, and 8-methoxypeucedanin heavily decreased RGR and RCR. Bergapten and imperatorin differed by the lowest RGR values and rather high RCR values. The effects caused by these two coumarins indicate specific postingestive toxicity. The results obtained in this study add to the reputation of coumarins to be an effective chemical defense, postulating that chemical diversity is a necessary trait for well-defended plants.     

Microwave accelerated preparation of [bmim][HSO4] ionic liquid: an acid catalyst for improved synthesis of coumarins

A efficient and easy method for preparation of (1-butyl-3-methyl-imidazolium hydrogen sulphate) ionic liquid using sodium bisulphate in place of concentrated sulphuric acid by microwave irradiation had been developed by us with manifold reduction in time. Further, this acidic room temperature ionic liquid has been exploited for the synthesis of coumarins under microwave irradiation and solventless conditions in short duration of time with quantitative yields, for the first time.     

The antioxidant activity of new coumarin derivatives

The antioxidant activity of two synthesized coumarins namely, N-(4,7-dioxo-2- phenyl-1,3-oxazepin-3(2H,4H,7H)-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 5 and N-(4-oxo-2-phenylthiazolidin-3-yl)-2-(2-oxo-2H-chromen-4-yloxy)acetamide 6 were studied with the DPPH, hydrogen peroxide and nitric oxide radical methods and compared with the known antioxidant ascorbic acid. Compounds 5 and 6 were synthesized in a good yield from the addition reaction of maleic anhydride or mercaptoacetic acid to compound 4, namely N'-benzylidene-2-(2-oxo-2H-chromen-4-yloxy)acetohydrazide. Compound 4 was synthesized by the condensation of compound 3, namely 2-(2-oxo-2H-chromen-4-yloxy) acetohydrazide, with benzaldehyde. Compound 3, however, was synthesized from the addition of hydrazine to compound 2, namely ethyl 2-(2-oxo-2H-chromen-4-yloxy)acetate, which was synthesized from the reaction of ethyl bromoacetate with 4-hydroxycoumarin 1. Structures for the synthesized coumarins 2-6 are proposed on the basis of spectroscopic evidence.     

Identification of eight coumarins occurring with psoralen,xanthotoxin, and bergapten on leaf surfaces

Surface extracts of the leaves of five species in the Umbelliferae,Citrus limon (Rutaceae), andPsoralea bituminosa (Leguminosae) were examined for the presence of coumarins, after a previous study had shown the presence of three psoralens. In the current investigation eight more coumarins were identified by mass spectrometric techniques: the simple coumarins scopoletin, scoparone, and osthol, the linear furanocoumarins imperatorin and phellopterin, the angular furanocoumarins angelicin and pimpinellin, and the pyranocoumarin seselin. Five of these occur inApium graveolens, and scopoletin, scoparone, and imperatorin were each found in three of the species examined. The co-occurrence of all these coumarins on the surface may be significant in communication between the plant and its environment.     

Green Synthesis of Novel Class of Azo Dyes Based on Naphthols,Coumarins, and Phenols with Molybdate Sulfuric Acid

A new series of polycyclic aromatic azo dyes based on naphthols, coumarins, and phenols were efficiently synthesized by the diazotization of 7-amino coumarins in the presence of catalytic amounts of molybdate sulfuric acid (MSA) followed by coupling reactions. The diazotization and subsequent azo-coupling generated the related azo dyes at 0–5°C in short reaction times with a simple experimental procedure.     

Absorption-emission spectra studies of 3-hetarylcoumarins

The synthesis of several coumarins substituted with a five-membered heterocyclic ring at the 3-position have been synthesised. The hetaryl rings substituted at the 3-position are the furyl, oxazolyl and the oxadiazolyl systems. The 3-furylcoumarins were prepared by reacting salicylaldehyde derivatives with a furylacetonitrile derivative. The oxazolyl and the oxadiazolyl derivatives were synthesised from coumarin-3-carboxylic acid derivatives by the usual routes. The absorption characteristics of these compounds have been recorded.     

微波辐射促进合成系列7-二乙氨基类香豆素及其荧光性质的研究

本文采用微波辐射技术合成了系列7-二乙氨基类香豆素,并通过红外光谱、核磁共振谱进行了结构表征。测试了所合成化合物的吸收光谱和发射光谱,研究了不同溶剂对荧光性能的影响。结果表明:与传统合成方法相比,该方法具有反应时间短、产率高等优点。且所合成的化合物随着溶剂极性的增大均表现为正溶剂化显色,且斯托克斯位移较大。