1,3-偶极环加成反应合成螺噻唑并[3,2-a]嘧啶类化合物

通过2-芳亚甲基-6,7-二氢-5H-噻唑并[3,2-a]嘧啶-3-酮(1a～1j)与甲亚胺叶立德(经靛红与肌氨酸反应原位生成)进行的l,3-偶极环加成反应,合成了10个新的螺噻唑并[3,2-a]嘧啶类化合物2a～2j.采用NMR、质谱、IR、元素分析以及X射线单晶衍射等多种谱学技术对产物2a～2j进行了结构表征,研究结果表明此类反应具有高度的立体选择性和区域选择性.     

选择性串联合成功能化的苯并[b][1,4]二氮杂?化合物

以取代的邻苯二胺、噻唑-2-甲醛和乙炔二甲酸二乙酯为原料,无水乙醇为溶剂,通过串联反应(亲核加成、脱水、环合和质子转移等)合成了12种新颖的取代的3,4-二乙氧羰基-2-(噻唑-2-基)苯并[b][1,4]二氮杂?化合物.由于化学/区域选择性,在同一反应不同条件下分别得到了烯胺型和亚胺型苯并[b][1,4]二氮杂?的异构体,通过考察反应条件对产物异构体选择性的影响,研究产物选择性的变化规律,为实现选择性合成苯并[b][1,4]二氮杂?化合物提供简便的合成思路.采用密度泛函(DFT)方法在B3LYP/6-31G基组水平上对反应原料和两种目标化合物进行量化计算,从原子布居电荷的角度,进一步对反应的选择性规律进行理论解释,并且在此基础上提出了合理的反应机理.     

新型2-苯并呋喃取代薁类衍生物的合成

以溴乙酰溴为酰化剂,对2-甲基薁进行酰基化反应,其酰化产物通过与水杨醛缩合,溴代反应及硫代乙酰胺的环化反应,以较好的收率,高选择性合成了新型的1-(2-苯并[6]呋喃酰基)薁和3-(2-苯并呋喃基)薁类[1,2-c]噻吩类衍生物,其结构经1H NMR,IR及元素分析表征.     

[Bmim]Br-AlCl3催化苯与1-十二烯烃烷基化反应机理的研究

利用同位素取代法考察了[Bmim]Br-AlCl3催化苯与1-十二烯烃烷基化反应机理. 首先进行了[Bmim]Br-AlCl3催化氘代苯与1-十二烯烃的反应, 通过GC-MS及NMR分析产物十二烷基苯同分异构体的结构, 验证了氘原子与产物侧链1-位碳相连的结论. 示踪氘原子推导了烷基化反应机理, 结果表明: [Bmim]Br-AlCl3催化苯与长链烯烃的烷基化反应是由[Al2Cl6Br]－发生平衡移动, 生成Lewis酸AlCl3引发的; AlCl3吸电子作用使1-十二烯烃的π电子向1-碳转移, 在烯烃的2-碳上形成正电荷中心, 碳正离子与苯发生亲电反应生成不稳定的σ络合物, 与σ络合物环上的σ-C相连的D＋转移到负电的侧链1-C上形成C—D键, AlCl3离去, 生成产物2-十二烷基苯. Lewis酸催化机理为离子液体催化苯与长链烯烃的反应中, 2-十二烷基苯选择性高于H质子催化产物提供了理论依据.     

咪唑阴离子型碱性离子液体的合成及其催化Knoevenagel缩合反应

设计合成了由1-丁基-3-甲基咪唑阳离子与咪唑阴离子搭配的[bmim]Im新型碱性离子液体并对其碱性进行研究.[bmim]Im离子液体的碱性与[bmim]OH的碱性接近且强于[bmim]OAc.在水溶液及室温条件下,2%的[bmim]Im离子液体对系列芳香醛与活泼的亚甲基化合物之间的Knoevenagel缩合反应具有较好的催化性能,目标产物的收率达到86%～95%,选择性为100%.同时,该催化剂体系具有良好的循环性能.     

新型2-苯并呋喃取代奠类衍生物的合成

以溴乙酰溴为酰化剂，对2-甲基奠进行酰基化反应，其酰化产物通过与水杨醛缩合，溴代反应及硫代乙酰胺的环化反应，以较好的收率，高选择性合成了新型的1-（2-苯并[b]呋喃酰基）奠和3-（2-苯并呋喃基）奠类[1，2-c]噻吩类衍生物，其结构经1HNMR，IR及元素分析表征。     

选择性合成双[噻吩并[2,3-d]嘧啶-4(3H)-酮]

以2-氨基-4-三氟甲基-5-甲基-噻吩-3-羧酸乙酯(1)为起始原料制得膦亚胺2.在碳酸钾的催化下,膦亚胺2与芳基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上2,2’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]3;膦亚胺2与烷基异氰酸酯和伯二胺的氮杂Wittig反应制得嘧啶环上3,3’取代的双[噻吩并[2,3-d]嘧啶-4(3H)-酮]4.化合物3的核磁共振氢谱表明关环反应在嘧啶环的2,2’位;化合物4的核磁共振氢谱表明关环反应在嘧啶环的3,3’位.对合成反应机理的推导及目标产物核磁共振氢谱数据的分析解释了此合成反应的选择性.     

微波辐射下硅磺酸催化的香豆素并[4,3-d]吡唑并[3,4-b]吡啶的高效合成

在硅磺酸催化下,通过微波辐射的3-酰基香豆素与5-氨基吡唑的反应,一步高产率地合成了一系列香豆素并[4,3-d]吡唑并[3,4-b]吡啶衍生物.该方法具有反应时间短(20~30 min)、选择性好、产率高、操作简单和环境友好等优点.产物的结构经红外光谱、核磁共振谱及高分辨质谱予以确定.     

6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物的合成新方法

研究了6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺的合成新方法.以相对廉价的2,5-二羟基-1,4-二噻烷和丙二腈为原料,依次通过Gewald反应、芳环溴代、缩合、环合以及Dimroth重排四步反应得到目标产物6-溴-N-[3-氯-4-(3-氟苄氧基)苯基]噻吩[2,3-d]并嘧啶-4-胺,总产率为56.9%.用1H NMR,IR,MS和HRMS对产物进行了结构表征.并应用该方法,合成了一系列的6-溴-N-芳基噻吩[2,3-d]并嘧啶-4-胺类化合物.研究表明该方法具有原料易得、操作简便、收率较高,且产物容易分离纯化等优点.     

碱性离子液体[bmim]OH促进一锅串联合成七元硫杂环化合物

碱性离子液体[bmim]OH能快速、高选择性地催化有机硫试剂与丙烯酸乙烯酯之间的直链加成反应.通过这种方法,合成了12种β-烷基硫取代的丙酸乙烯酯类含硫化合物.进一步调控反应温度和时间可以实现Michael加成和分子内的加成-消除反应的一锅串联成环反应.利用碱性离子液体[bmim]OH选择性促进巯基亲核性的策略,成功地合成了6种七元硫杂环化合物,对产物进行了表征确定.     

1,3-偶极环加成反应与控制自由基聚合结合制备嵌段共聚物的研究进展

炔基与叠氮基的1,3-偶极环加成反应作为点击化学的精髓,反应高效,条件温和.通过它与控制自由基聚合结合,为制备多种拓扑结构嵌段共聚物提供了新途径,所得嵌段共聚物纯度高,分子量分布较窄.本文就1,3-偶极环加成点击反应与3种控制自由基聚合方法相结合在制备线型及非线型嵌段共聚物方面所取得的成就加以综述,并对今后的发展方向做...     

An expedient synthesis of pyrrolidinyl spirooxindole grafted 3-nitrochromanes through 1,3-dipolar cycloaddition reaction of azomethine ylides

A facile one-pot synthesis of pyrrolidinyl-spirooxindole grafted 3-nitrochromanes has been accomplished by 1,3-dipolar cycloaddition (1,3-DC) reaction of 3-nitrochromenes with azomethine ylides generated in situ from isatin and secondary amino acids. The regio- and stereochemical outcome of the cycloaddition reaction was ascertained by X-ray crystallographic analysis.     

An easy access to novel steroidal dispiropyrrolidines through 1,3-dipolar cycloaddition of azomethine ylides

A facile one-pot synthesis of novel steroidal dispiropyrrolidines has been accomplished by 1,3-dipolar cycloaddition reaction of various azomethine ylides derived from isatin/acenaphthenequinone/ninhydrin and sarcosine with various estrone derivatives as dipolarophiles, in good yield. The effect of various solvents on the 1,3-dipolar cycloaddition reaction are also studied.     

Novel 1,3-dipolar cycloaddition of diazocarbonyl compounds to alkynes catalyzed by InCl3 in water

The first intermolecular 1,3-dipolar cycloaddition of diazocarbonyl compounds with alkynes was developed by using an InCl(3) catalyzed cycloaddition in water. The reaction was found to proceed by a domino 1,3-dipolar cycloaddition-hydrogen (alkyl or aryl) migration.     

On the synthesis of geminally functionalized heterocyclic aminocarboxylic acid esters

The title compounds 5 can be easily obtained by two alternative procedures: 1,3-dipolar cycloaddition to benzamidocinnamates 3 prepared by methanolysis of the corresponding oxazolones 1 or methanolysis of the spirooxazolones 4 synthesized by 1,3-dipolar cycloaddition to oxazolones 1 . Both reaction sequences show the same stereo and regioselectivity.     

1,3-Dipolar cycloaddition for selective synthesis of functionalized spiro[indoline-3,3'-pyrrolizines]

The 1,3-dipolar cycloaddition reaction of dimethyl hex-2-en-4-ynedioate with azomethine ylides derived from reaction of L-proline with various isatins in methanol selectively resulted in the formation of functionalized spiro[indoline-3,3'-pyrrolizine]acrylates as main products and spiro[indoline-3,3'-pyrrolizine]propiolates as minor products.This result indicated that the electron-deficient alkyne has higher reactivity than that of electron-deficient alkene in 1,3-dipolar cycloaddition reaction.     

Substrate-controlled and site-selective [3+2] cycloadditions of N-heterocyclic carbene derived ambident dipoles

2-aryl thiocarbamoyl benzimidazolium and imidazolinium inner salts derived from benzimidazole and imidazoline carbenes are unique ambident C-C-S and C-C-N 1,3-dipolar systems, which undergo highly efficient and site-selective cycloaddition reactions with dimethyl acetylenedicarboxylate or dibenzoylacetylene to furnish spiro(imidazole-2,3'-thiophene) derivatives in excellent yields. When treated with ethyl propiolate, methyl acrylate or acrylonitrile, spiro(imidazole-2,3'-pyrrole) derivatives were formed in good yields. Theoretical studies revealed an asynchronous concerted mechanism for both the C-C-S and C-C-N 1,3-dipolar cycloaddition reactions. The site selectivity in the [3+2] cycloaddition reaction of ambident 1,3-dipoles was predictably regulated by both the electronic and steric effects of dipolarophiles.     

脱质子化1,3环加成石墨烯外在固定位上的贵金属纳米线(英文)

为研究纳米线的形成机理,通过密度泛函理论(DFT)研究了贵金属(铂)在脱质子化1,3-环加成石墨烯上的吸附.研究发现:(1)吸附在1,3-环加成石墨烯上的铂原子引起该结构的脱质子化过程并形成脱质子化1,3-环加成石墨烯;(2)贵金属在脱质子化1,3-环加成石墨烯上的锚定位是氮原子邻位的碳原子,这在邻位碳原子的平均巴德电荷分析(高达1.0e)中得到进一步的证实;(3)铂原子在相邻的脱质子化吡啶炔单元上形成金属纳米线,并且该纳米线比相应的铂团簇稳定得多;(4)电子结构分析表明,铂的吸附并没有从根本上改变脱质子化1,3-环加成石墨烯的电子性质.铂金属的掺杂使得Pt6团簇吸附形成的复合物呈现金属性,而Pt6纳米线形成的复合物则为半金属性.     

Binaphthol-derived bisphosphoric acids serve as efficient organocatalysts for highly enantioselective 1,3-dipolar cycloaddition of azomethine ylides to electron-deficient olefins

A variety of chiral bisphosphoric acids derived from binaphthols have been evaluated for enantioselective 1,3-dipolar cycloaddition reactions, revealing that the feature of the linker in the catalysts exerted great impact on the stereoselectivity. Among them, the oxygen-linked bisphosphoric acid 1a provided the highest level of stereoselectivity for the 1,3-dipolar cycloaddition reaction tolerating a wide range of substrates including azomethine ylides, generated in situ from a broad scope of aldehydes and α-amino esters, and various electron-deficient dipolarophiles such as maleates, fumarates, vinyl ketones, and esters. This reaction actually represents one of the most enantioselective catalytic approaches to access structurally diverse pyrrolidines with excellent optical purity. Theoretical calculations with DFT method on the formation of azomethine ylides and on the transition states of the 1,3-dipolar cycloaddition step showed that the dipole and dipolarophile were simultaneously activated by the bifunctional chiral bisphosphoric acids through the formation of hydrogen bonds. The effect of the bisphosphoric acids on reactivity and stereochemistry of the three-component 1,3-dipolar cycloaddition reaction was also theoretically rationalized. The bisphosphoric acid catalyst 1a may take on a half-moon shape with the two phosphoric acid groups forming two intramolecular hydrogen bonds. In the case of maleates, one phosphate acts as a base to activate the 1,3-dipole, and simultaneously, the two hydroxyl groups in the catalyst 1a may respectively form two hydrogen bonds with the two ester groups of maleate to make it more electronically deficient as a much stronger dipolarophile to participate in a concerted 1,3-dipolar cycloaddition with azomethine ylide. However, in the cases involving acrylate and fumarate dipolarophiles, only one hydroxyl group forms a hydrogen bond with the ester functional group to lower the LUMO of the C-C double bond and another one is remained to adjust the acidity and basicity of two phosphoric acids to activate the dipole and dipolarophile more effectively.     

Catalytic enantioselective 1,3-dipolar cycloadditions of nitrones with propioloylpyrazoles and acryloylpyrazoles induced by chiral π-cation catalysts

A chiral copper(II) complex of 3-(2-naphthyl)-l-alanine amide successfully catalyzes the enantioselective 1,3-dipolar cycloaddition reaction of nitrones with propioloylpyrazole and acryloylpyrazole derivatives. The asymmetric environment created by intramolecular π-cation interaction gives the corresponding adducts in high yields with excellent enantioselectivity. This is the first successful method for the catalytic enantioselective 1,3-dipolar cycloaddition of nitrones with acetylene derivatives. The 1,3-dipolar cycloadducts can be stereoselectively converted to β-lactams via reductive cleavage of the N-O bond using SmI(2).