Synthesis of N-Substituted （Z）-3-（ （2-Benzyl）-4-Ox opent-2-yl） Pyrrole-2,5-Diones （Maleimides）

A series of N-substituted （Z）-3-（（2-benzyl）-4-oxopent-2-yl）pyrrole-2,5-diones were synthesized and characterized. The compounds were synthesized from dimethyl-2-（（Z）-2-（benzylamino）-4-oxopent-2-en-3-yl） fumarate （9） and dimethyl acetylenedi-carboxylate followed by reaction with some amines in refluxing ethanol. The identification of the compounds were based on spectroscopic analysis such as 1R （infrared）, UV （ultraviolet）, ^1H-NMR （nuclear magnetic resonance） and the microanalysis of the elements （CHN （microanalysis）） data.

DSPE-PEG 2000 maleimide的合成

目的研究长循环靶向型脂质体中间体二硬脂酰磷脂酰乙醇胺-聚乙二醇-马来酰亚胺(phosphatidyl ethanolamine-polyethylene glycol-maleimide,DSPE-PEG 2000 maleimide)的新合成方法。方法用β-氨基丙酸和马来酸酐作为原料,合成中间体2;以聚乙二醇2000(PEG 2000)为原料合成关键中间体8;用(S)-(+)-甘油醇缩丙酮为起始原料合成DSPE;中间体8与DSPE对接,得到目标化合物。结果与结论目标化合物的结构经1H-NM R确证。该路线操作简便、条件温和,可以作为生产工艺研究的参考。

Synthesis of a benzoxazine monomer containing maleimide and allyloxy groups

A novel benzoxazine monomer 3-（4-allyloxy）phenyl-3,4-dihydro-2H-6-（N-maleimido）-l,3-benzoxazine （AMB） was synthesized and structure was confirmed by FT-IR, 1H NMR. Thermal analysis （DSC） of AMB showed the introduction of allyloxy group melting point and exhibited a narrow and symmetric curing exothermic window.

Reactivity Ratios for Microemulsion Copolymeriration of N-butyl Maleimide and Styrene

The oil-in-water microemulsion containing N-butyl maleimide(NBMI. M_1) and styrene(St, M_2) was prepared. The complexation properties of NBMI and St in microemulsion were investigated by means of 1H-NMR. With the participation of charge-transfer complex(CTC). four reactivity ratios and the relative reactivity of free monomers and CTC were obtained. The result was compared with that measured by Mayo-Lewis method.

Ultrasound assisted multicomponent reactions:A green method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines usingβ-cyclodextrin as a supramolecular reusable catalyst in water

We demonstrate a superficial method for the synthesis of N-substituted 1,8-dioxo-decahydroacridines using β-cyclodextrin as a supramolecular,biodegradable,and reusable catalyst in aqueous medium.The reaction product is in excellent yield with moderate to excellent selectivity.The mechanistic transformation presumably proceeds via a one-pot,multicomponent cyclization of dimedone in the presence of aromatic aldehydes and aromatic amines/INH,undergoing a tandem Michael addition reaction.The proposed approach in this study provides a highly efficient and environmentally benign route to N-substituted 1,8-dioxo-decahydroacridines.

Furans-Maleimides Diels-Alder Reactions in Protic Ionic Liquid

The authors have studied the Diels-Alder reactions between furan derivatives and maleimide derivatives in an ionic liquid and have found that higher reactivity can be obtained in a protic ionic liquid [Mim]Tf2N than in the conventional organic solvent. Furthermore, in the Diels-Alder reactions of 2- and 2,5-alkylfurans with N-alkylma- leimide, the reactivity increases by extending the alkyl chain length of N-alkylmaleimide. In addition, it was demon- strated that endo-selectivity increases when 2,5-disubstituted furans are used. These results will be explained by comparing the stability of the Diels-Alder adduct with that of the products obtained from the reactions of 2-substituted furans and 2,5-disubstituted furans.

Facile and Stereoselective Synthesis of N-Substituted Benzotriazole with Baylis-Hillman Adducts

A convenient method has been developed toward the stereoselective synthesis of N-substituted benzotriazole derivatives under mild conditions. The good stereolectivity, high yields and the simple procedure make the present protocol attractive.

A new semi-quantitative Surface-Enhanced Raman Spectroscopy (SERS) method for detection of maleimide (2,5-pyrroledione) with potential application to astrobiology

Nitrogen-containing heterocyclic compounds are fundamental biochemical components of all life on Earth and,presumably,life elsewhere in our solar system.Detection and characterization of these compounds by traditional solvent extraction,chromatographic separation,and GC-MS analysis require more sample mass than will be available from samples returned to Earth from Mars.With its small sample mass requirement,Surface Enhanced Raman Spectroscopy could be an appropriate technique for analysis of returned samples.We have developed a SERS method for the detection of maleimide(2,5-pyrroledione),an N-containing heterocycle with a structure that is widespread in biochemicals.This semi-quantitative methodology accurately determines maleimide concentration in the range from 60 mg/mL to 120 mg/mL.We present a maleimide SERS standard spectrum which will be useful as a reference for future works.The present work demonstrates an easy,accurate,and effective method for the non-destructive qualitative and semi-quantitative study of maleimide as a first step toward developing a method for analysis of related compounds.

Studies on the Self-condensing Vinyl Polymerization of a Novel Maleimide Inimer

The self-condensing vinyl polymerization(SCVP) of a novel maleimide inimer(initiator-monomer) 1, N-(4-α-bromobutyryloxy phenyl) maleimide with the complex of CuBr/Bipy(2, 2′-bipyridine) as the catalyst was studied. GPC was used to determine the molecular weight and the results show that the molecular weight increases exponentially with polymerization time during the first hour, and then the rate of increase molecular weight slows down. The molecular weight also increases with increasing dosage of the catalyst. The coincidence of the molecular weights determined by 1H NMR and GPC proves that the polymer obtained from the SCVP of inimer 1 has a linear structure, which is further verified by 13C NMR spectrum. A hyperbranched polymer was obtained by the copolymerization of inimer 1 and styrene.

Copolymerization of N-4-Dibenzoylmethane Maleimide with Styrene

The copolymer of N-4-dibenzoylmethane maleimide (p-DBMI) with styrene (St) was prepared and characterized by gel permeation chromatography, thermal analysis and spectroscopy.

Conversion of 3,4-Dihydroxypyrrolidine-2,5-Dione to Maleimide through Tosylation and Mechanism Study by DFT

Pyrrolidine-2,5-dione and maleimide are important scaffolds of many organic substances, and their derivatives are now attracting more and more interests from researchers in organic synthesis, medicinal chemistry, and drug development. Tosyloxy (-OTs) group is an important functional group widely used in organic synthesis, because it can be readily prepared from alcohols and is an excellent leaving group. However, surprisingly, substances bearing tosyloxy groups on pyrrolidine-2,5-dione or maleimide scaffolds are very rare. In this study, we discovered that, when treated with TsCl/Et3N,?trans-3,4-dihydroxypyrrolidine-2,5- dione will eliminate a TsOH molecule to form monotosyloxymaleimide. Thermodynamic and kinetic factors affecting this reaction were investigated by theoretical computation using density functional theory (DFT), and the possible reaction mechanism was proposed based on the computation results. Our results showed that tosylates of trans -3,4-dihydroxypyrrolidine- 2,5-dione, either monotosylate or ditosylate, are thermodynamically instable and may spontaneously convert to maleimides. This knowledge could be useful in understanding the properties of pyrrolidine-2,5-diones and maleimides, as well as the related organic synthesis.

A new method for the synthesis of N-substituted pyrroles

An unexpected reaction of 10-bromomethyl-12-oxocalanolide A（2） with primary amine was demonstrated and studied. Consequentially,a new method for the preparation of N-substituted pyrroles starting fromγ-halo-α,β-unsaturated ketone was presented.

Synthesis of Methylated β-Cyclodextrins Derived Optically Active Poly(N-diphenylmethyl maleimide)

The methylated β-cyclodextrins derived optically active polymers are firs synthesized through asymmetric polymerization of N-diphenylmethyl maleimide with lithium salt of heptakis(2,6-O-dimethyl) β-cyclodextrin (DM-β-CD) as an initiator. The resulting polymers show negative specific rotation which is opposite in sign to that of DM-β-CD. The asymmetric induction is further confirmed by circular dichroism. The structure is characterized by IR and NMR spectroscopies

STEREOSTRUCTURAL DETERMINATION OF ADDITION PRODUCTS FROM ISOFURANOGERMACRENE AND MALEIMIDE BY NMR TECHNIQUES

The stereostructures of the title compounds were shown to be represented by (A) and (B).

N-Substituted benzoxazolyl ureas and thioureas in Biginelli reaction promoted by trifluoromethane sulfonic acid:An efficient and convenient synthesis of substituted benzoxazolyl 3,4-dihydropyrimidine(1H)-(thio)-ones

An efficient synthesis of 3,4-dihydropyrimidine 2 （1H）-ones and thiones （3,4-DHPMs） core was prepared by one-pot threecomponent Biginelli condensation and which was catalyzed by trifluoromethane sulfonic acid. The classical BigneUi reaction has been extended by the use of N-substituted benzoxazolyl semicarbazides and thiosemicarbazides and this method has the advantage of excellent yields and short reaction times. ？2009 M. Saranga Pard. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Theoretic Study of 3-(4-N-Maleimido)-phenyl-2,4-dihydro-2H-1,3-benzoxazine Molecular Structure,Spectrum and Thermodynamic Properties

The geometric structures,electronic absorption spectrum,and thermodynamic pro-perties of 3-（4-N-maleimido）-phenyl-2,4-dihydro-2H-1,3-benzoxazine molecule were studied at the B3LYP/6-311＋G＊ level by density functional theory.The results show that three rings of this molecule are in different planes.In gas,absorption wavelength of the lowest energy excitation was obtained at 503 nm,and solvents made it blue-shifted by 3-7 nm,both corresponding to the electron transition of HOMO → LUMO.At 298.15 K,the standard molar formed enthalpy and free energy of the title compound molecule were-549.43 and-273.37 kJ·mol-1,respectively.

含吡唑酮和马来酰亚胺结构单元的含氮杂环化合物的合成研究

吡唑酮环是一类具有抗菌、解热、镇痛等生物活性的重要结构母核,而且吡唑酮及其衍生物更是具有抗炎、抗癌等作用。马来酰亚胺骨架是一类广泛存在的药物、天然产物、功能材料、生物活性分子中的重要结构单元,此外马来酰亚胺骨架也是各类药物分子与天然产物中的关键结构单元。本文以吡唑酮烯烃与马来酰亚胺烯烃为底物合成含有吡唑酮和马来酰亚胺结构单元的含氮杂环化合物,并对合成产物的不同实验条件进行筛选优化,获得最佳的反应条件。结果表明,在以二氯甲烷为反应溶剂,20 mol%4-二甲氨基吡啶催化作用下,马来酰亚胺烯烃与吡唑酮烯烃物料配比为1/1.5的反应条件下可得到较高产率的产物,同时缩短合成目标产物的反应时间,高效合成目标产物,为进一步考察反应的普适性进行铺垫。

锰催化的芳香叔胺和马来酰亚胺氧化成环反应

本文提出了一种锰催化芳香叔胺和马来酰亚胺氧化成环的新方法,并完成了反应条件优化、底物拓展及相关机理研究。该方法采用多吡啶作为配体与MnCl_(2)构筑高性能催化体系,选用叔丁基过氧化氢(tBuOOH)为氧化剂,在较低的温度(40℃)实现芳香叔胺和马来酰亚胺氧化成环,一步法直接合成12种吡咯并[3,4-c]喹诺酮类分子,最高核磁产率达90%,分离收率达80%。机理研究表明,反应过程涉及到单电子转移的自由基反应机理,其中tBuOOH在催化剂作用下生成的tBuOO·在氧化过程中应该起主导作用。

乙酸乙烯酯-马来酰亚胺共聚物及其醇解物的制备

乙酸乙烯酯(VAc)的溶液聚合一般以甲醇为溶剂,但以甲醇为溶剂进行VAc与马来酰亚胺(HMI)的共聚研究目前较少报道。文中采用Finemen-Ross方法计算了VAc与HMI在甲醇中的竞聚率,分别是rHMI=4.15和rVAc=1.76×10^(-3)。之后采用饥饿投料法获得了一系列含有不同HMI含量的聚乙酸乙烯酯共聚物(PVAc/HMI),醇解后得到聚乙烯醇共聚物(PVA/HMI)。结果显示,随HMI投料比从0%(摩尔分数)增加到4%,所得PVAc/HMI的Tg上升了20%、弹性模量增加了67%,PVA/HMI的Tg上升了12%。

高耐热线性环氧树脂的合成及流变特性研究

通过N-苯基马来酰亚胺(N-PMI)与4,4′-二氨基二苯甲烷(DDM)迈克尔加成反应合成了一种改性二元胺(PDP),并与双酚A型环氧树脂(EP)反应制备了线性环氧树脂。通过核磁共振氢谱(HNMR)、红外光谱法(FTIR)和差式扫描量热法(DSC)研究了PDP的化学结构与性质,并通过DSC,FTIR和凝胶渗透色谱法(GPC)研究了线性环氧树脂耐热性(T_(g))及流变特性。结果表明:随着反应时间延长,EP/PDP(1∶1摩尔比)树脂体系黏度由0.55 Pa·s增至57 Pa·s,T_(g)由55℃升至120℃,平均分子质量由4651增至25096;随着温度的降低,体系黏度由200℃的0.55 Pa·s增加至140℃的60 Pa·s。不同比例EP/PDP树脂体系的T_(g)随PDP过量的比例增大而升高,当EP∶PDP为0.8∶1时,T_(g)为121℃,在相同反应时间,体系黏度随PDP过量比例的增大而增大。