区域选择性合成2-硝基-5, 10, 15, 20-四芳基金属卟啉

研究了以硝酸盐为硝化剂与中位四芳基金属卟啉反应、选择性合成2-硝基-5,10,15,20-四芳基卟啉的方法,发现配位金属离子、中位苯环上的取代基对反应产率和时间有明显的影响,当金属离子为铜、镍时,可得定量的2-硝基卟啉,为锌时,完成反应的时间延长,反应产率迅速下降。推电子的甲氧基能加快反应的进行,吸电子的氯原子则延缓反应的进行。讨论了金属离子和取代基团对反应影响的原因。     

Ni(PPh3)2Cl2催化2-氯嘧啶与芳基硼酸的Suzuki-Miyaura偶联反应

本文在Ni(PPh3)2 Cl2催化下顺利实现了不同取代基2-氯嘧啶与芳基硼酸的Suzuki-Miyaura偶联反应.实验表明,取代基的电子效应和空间位阻效应对2-氯嘧啶的反应活性影响较小.该反应产率良好,官能团耐受性好,为2-芳基嘧啶衍生物的合成提供了一类简单有效的方法.     

硅烷基取代苯并二硫杂环戊烯的合成及电化学性质

以苯并-1,3-二硫杂环戊烯为原料,通过金属化反应以及锂化二硫杂环戊烯与氯代硅烷反应合成了系列2-硅烷基取代苯并-1,3-二硫杂环戊烯化合物.测定了化合物的氧化电位,发现硅的引入导致苯并-1,3-二硫杂环戊烯的氧化电位明显降低,给体的给电子能力增强.     

合成2,5-二芳基噻唑衍生物的新方法

噻唑环作为一类重要的五元芳香杂环,其衍生物具有多种生物活性,被广泛应用在医药方面.以价廉易得的不同取代苯甲酸为原料,经酰化反应、硫代反应、环合反应和Heck反应合成了2,5-二芳基噻唑衍生物.重点在于优化Heck反应的条件,进行可能反应机理的探讨.该方法具有反应条件温和、操作简单及底物的普适性良好等优点,为2,5-二芳基取代噻唑类化合物的合成提供了新的方向.     

可见光催化合成C-3位芳酰基取代的2-芳基-2H-吲唑衍生物

基于C-H键官能团化反应策略,在无过渡金属条件下,以2-芳基-2H-吲唑为底物,芳基酮酸为芳酰基自由基源,利用2,4,5,6-四(9-咔唑基)-间苯二腈(4CzIPN)作为光催化剂,通过可见光催化脱羧偶联反应,合成了一系列C-3位芳酰基取代的2-芳基-2H-吲唑衍生物,产率59%-81%。所得产物结构经过氢谱、碳谱和高分辨质谱表征确证。该方法反应条件温和,具有良好的底物适用性和官能团耐受性,为2H-吲唑的C-3位C-H键芳酰基化反应提供了新途径。     

新型含咔唑双膦配体-钯催化 Suzuki 反应

 以 3-溴苯甲醚为原料合成了新型双膦配体 6,6′-二甲氧基-2,2′-二 (二-N-咔唑基膦)-1,1′联苯, 并将该配体与钯组成的配合物用于对溴苯甲醚和苯硼酸的 Suzuki 偶联反应, 考察了溶剂、碱、底物/催化剂摩尔比、膦/钯摩尔比对偶联反应的影响. 结果表明, 该催化体系在 1,4-二氧六环中催化对溴苯甲醚和苯硼酸的 Suzuki 偶联反应得到 99% 的分离产率. 同时, 该催化体系用于其它芳基溴和苯硼酸的 Suzuki 偶联反应也表现出很好的催化性能, 即使芳基溴有较大的空间位阻或具有取代基也能获得很好的结果.     

活性炭载铁催化剂作用下几种典型芳烃一步氧化羟基化反应研究

以过氧化氢为氧化剂, 在乙腈介质中研究了几种典型芳烃的一步羟基化反应, 考察了底物取代基的供吸电子性质、 空间位阻等对羟基化反应的影响, 并推测了其反应机理.     

环钯化二茂铁亚胺-三苯基膦配合物的合成、表征及催化Suzuki反应研究

为筛选高效催化Suzuki反应的催化剂, 合成了3种新的环钯化二茂铁亚胺-三苯基膦配合物2~4, 经元素分析(或HRMS)、 红外光谱和核磁共振谱对其结构进行了表征, 并通过X射线单晶衍射测定了化合物3的晶体结构. 这些化合物容易合成, 在空气和溶液中稳定, 可用作芳基溴及杂芳基溴与苯基硼酸偶联的Suzuki反应催化剂. 使用摩尔分数为0.01%的催化剂3, 以2倍量的K3PO4为碱, 于110 ℃下, 在甲苯中反应5~15 h, 使具有不同电子和位阻效应的取代芳基溴及杂芳基溴能以较高的产率与苯基硼酸反应生成偶联产物; 与溴苯相比, 带吸电子基的溴苯反应活性较高, 催化剂的摩尔分数降低至0.001%时, 仍能得到较高产率, 而带强给电子基的溴苯如4-溴苯甲醚及带邻位取代基的溴苯在其它条件相同时, 需要延长反应时间才能得到较高的产率.     

3-杂环基硫取代-1,3,4,5-四氢-2-氧代-苯并氮杂衍生物的合成

以芳酰肼为原料,合成了一系列3-巯基-5-芳基-1,2,4-三唑、2-巯基-5-芳基-1,3,4-噁二唑和2-巯基-5-芳基-1,3,4-噻二唑,并通过硫原子对3-溴-2-氧代-苯并氮杂3-位上的亲核取代反应将杂环化合物引入了苯并氮杂的结构当中,合成了32个新的苯并氮杂杂环衍生物.为提高其在有机溶剂中的溶解性,在苯并氮杂的N原子上引入乙酸乙酯和乙酸叔丁酯基取代基,合成了36个新衍生物.所有化合物经质谱、核磁共振谱及元素分析确证了结构并初步测定了抗菌活性.     

2-芳基戊二酸酯的合成

在K2CO3-TEBA相转移催化体系中,4位或2位含有—NO2的苯磺酰基乙酸酯与α,β-不饱和酯发生加成-重排反应,制得2-芳基戊二酸酯,其收率较高(73%～87%)。研究了反应物-芳磺酰基乙酸酯苯环上取代基对加成-重排反应的影响,发现只有当芳环上4位或2位有硝基时,在K2CO3-TEBA相转移催化体系中,芳磺酰基乙酸酯与α,β-不饱和酯反应才可发生加成-重排反应,生成2-芳基戊二酸酯,其机理可能是芳磺酰基乙酸酯与α,β-不饱和酯首先发生Michael加成反应,随后加成产物发生分子内的亲核取代,酸化后脱去SO2得2-芳基戊二酸酯。而当芳环上4位或2位含有给电子基团(如,甲基)或弱吸电子基团(如,氯)时,却只能发生正常的Michael加成反应,生成相应的2-芳磺酰基戊二酸酯。     

A Highly Diastereoselective Three‐component Domino Reaction in Water Yielding Poly‐substituted 4,5‐Dihydropyrroles

An efficient methodology for highly diastereoselective synthesis of poly‐substituted 4,5‐dihydropyrrole derivatives from readily available common reactants in water has been developed. During domino processes, the formation of pyrrole skeleton and its C2‐hydroxylation and C3‐arylamination were readily achieved via metal‐free [3+2] heterocyclization in a one‐pot operation.     

Synthesis of 2,3,6-trisubstituted pyridines by transition-metal free cyclization of 1,3-diynes with amino acids

Amino acids are firstly employed in transition-metal free heterocyclization reaction of 1,3-diynes in the presence of K₃PO₄ and DMSO at 120 °C. This method produces 2,3,6-trisubstituted pyridines with up to 86% yield. The –CO₂H group on the amino acids is crucial for this heterocyclization reaction. The mechanism of such a heterocyclization reaction is discussed, as well.     

Chemo- and regioselective synthesis of 2-alkylidenetetrahydrofurans bearing a chiral sulfur atom by domino reactions of sulfoximines

The addition of the dianion of Johnson’s sulfoximine to α,ω-halogenoesters evolves by an intramolecular heterocyclization to provide a direct access to 2-alkylidenetetrahydrofurans bearing a chiral sulfur atom via domino addition-elimination/S_N reactions.     

Etude du mécanisme de la réaction de hantzsch des thiazoles. II. premiére étape: Action des cétones-α halogénées sur les thioamides

The mechanism of the Hantzsch heterocyclization reaction is studied. The α-haloketones behavior is an example of ambident reactivity. We show, by kinetic determinations and from literature data, that the interaction of α-haloketones with thioamides begins by a direct substitution of the halogen atom by the sulfur atom.     

Abnormal alkylation of N-benzylidene-α-aminoester anions with α-haloesters

The title anions, when α-alkyl substituted, alkylate selectively in the γ-position with hindered α-bromoesters. A lower degree of hindrance in either or both reactants tends to favour α-alkylation.     

Straightforward access to pyrazines, piperazinones, and quinoxalines by reactions of 1,2-diaza-1,3-butadienes with 1,2-diamines under solution, solvent-free, or solid-phase conditions

The preparation of tetrahydropyrazines, dihydropyrazines, pyrazines, piperazinones, and quinoxalines by 1,4-addition of 1,2-diamines to 1,2-diaza-1,3-butadienes bearing carboxylate, carboxamide, or phosphorylated groups at the terminal carbon and subsequent internal heterocyclization is described. The solvent-free reaction of carboxylated 1,2-diaza-1,3-butadienes with the same reagents affords piperazinones, while phosphorylated 1,2-diaza-1,3-butadienes yield phosphorylated pyrazines. The solid-phase reaction of polymer-bound 1,2-diaza-1,3-butadienes with 1,2-diamines produces pyrazines.     

2-Aminothiophene. Heterocyclization of benzylthionitriles

Synthesis of unstable 2-aminothiophene by way of its hydrochloride salt has been achieved in excellent yield. The key reaction in the scheme involves a novel heterocyclization of benzylthionitriles, which would appear to have general utility. Spectral and physical properties are tabulated and a possible mechanism is proposed.     

Electrophilic heterocyclization of unsaturated sulfur and phosphorus compounds (review)

The literature on the electrophilic heterocyclization of unsaturated sulfur and phosphorus compounds has been reviewed. The factors influencing the reactivity of unsaturated compounds in such reactions are discussed, and data on the stereo-chemistry of the addition are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–302, March, 1986.     

A practical, one-pot synthesis of highly substituted thiophenes and benzo[b]thiophenes from bromoenynes and o-alkynylbromobenzenes

An efficient synthesis of thiophenes and benzo[b]thiophenes has been developed from easily available bromoenynes and o-alkynylbromobenzene derivatives. This novel one-pot procedure involves a Pd-catalyzed C-S bond formation using a hydrogen sulfide surrogate followed by a heterocyclization reaction. Moreover, in situ functionalization with selected electrophiles further expands the potential of this methodology to the preparation of the corresponding highly substituted sulfur heterocycles.     

液-液界面制备近红外荧光Ag_2S量子点

利用液-液界面反应体系,使分别溶解在油相中的银前体和水相中的硫前体在液滴界面发生反应,在室温条件下成功制备出近红外荧光Ag_2S量子点。采用透射电子显微镜(TEM)、X-射线衍射光谱(XRD)、傅立叶变换红外(FT-IR)光谱和荧光光谱等对产物进行了表征。结果表明,此方法成功制得了粒径较均一的Ag_2S量子点,纯化后经加热熟化处理其量子产率可达2.68%。另外实验发现,通过改变投料比即可实现Ag_2S量子点的粒径控制及荧光发射峰波长调控(1 170nm至1 279nm)。