绿色催化氧化合成邻硝基苯甲醛——一个氧化合成教学实验

采用“科学问题为目标导向”的实验教学指导原则,将邻硝基苯甲醛的绿色合成工艺开发为有机化学基础实验,丰富了绿色氧化反应在实验教学中的应用。本新创实验以水溶性2-(2,2,6,6-四甲基-4-亚哌啶基-1-氧化物)乙酸(简称TEMPO-COOH)为催化剂,在摩尔分数0.1%用量下,催化次氯酸钠氧化邻硝基苄醇,实现了重要有机合成中间体邻硝基苯甲醛的高选择性绿色催化合成,产率达93%,纯度>99%。作为本科生基础教学实验,本案例不仅涉及多种有机化学实验基本操作,还包含反应监测、结构表征、纯度分析等重要环节,同时还融入了绿色化学理念和有机合成方法学研究的实验探究过程。该新创实验所用试剂环境友好,安全性高,教学时长约为3–4 h,非常适合用于有机化学基础实验教学。以本实验方案为蓝本,结合有关氧化反应研究进展的微课学习和拓展练习,实现了理论知识与合成实践之间的有效互动,提升了化学专业本科生解决较为复杂有机合成问题的综合能力,提高了化学类人才的培养质量。     

水相中锌促进的羰基化合物频哪醇偶联反应实验设计

介绍水相中锌促进的羰基化合物频哪醇偶联反应的实验设计。通过苯甲醛频哪醇偶联反应得到相应的1,2-二苯基．1,2-乙二醇,学习水相有机反应和微量反应的基本操作,加强基础研究、绿色化学与有机化学实验之间的紧密联系。     

推荐一个大学有机化学实验:1-苯基三氮烯的合成

介绍了一个适合化学和化工专业开设的大学有机化学实验。首先苯胺在亚硝酸钠和浓盐酸的作用下发生重氮化反应生成苯基重氮盐,继而与四氢吡咯偶联得到1-苯基三氮烯。实验涉及低温反应、重结晶和熔点测定等实验操作技术以及红外光谱和核磁共振等化合物结构鉴定方法。其反应机理包括重氮化和偶联反应。该实验具有原料价廉、收率高、反应时间短和操作简便等特点,有利于培养和提高学生的实践能力和创新能力。     

一锅法合成间羟基苯甲醛工艺研究

以间硝基苯甲醛为原料,采用"一锅法"经氯化亚锡还原、重氮化、水解制得间羟基苯甲醛,研究了物料摩尔比、还原反应时间、还原反应温度、重氮化时间、亚硝酸钠用量等参数对产物收率的影响。结果表明,在优化工艺条件(间硝基苯甲醛与二水合氯化亚锡的摩尔比为1∶3、还原温度90℃、还原时间90min、重氮化时间75min、亚硝酸钠为1.4g)下,间羟基苯甲醛的收率达到76.5%。产物经红外光谱和核磁共振谱确认。该合成技术工艺过程简单,生产安全,环境友好,产品收率高,易于生产。     

富烯与α-萘基锂反应的研究

本文研究了6,6-二烷基富烯与α-萘基锂反应的立体结构和溶剂效应。首次发现了富烯与有机锂的还原偶联反应。在乙醚-THF中α-萘基锂与6,6-二甲基、二乙基和甲基乙基富烯发生环外双键的加成、α-氢攫取、还原和还原偶联的竞争反应。与6-甲基-6-正丙基,正丁基,异丁基富烯发生还原偶联反应.与n=4,5,6的6,6-n亚甲基富烯分别进行α-氢攫取、还原和还原偶联反应.在1:1的乙醚-石油醚中,除6,6-四亚甲基富烯发生α-氢攫取外,其他所有富烯主要进行加成反应。利用上述反应合成一些新的取代和桥联双(环戊二烯基)钛、锆衍生物。     

创新性综合实验:4-苯基-2-咪唑啉酮的合成与表征

“4-苯基-2-咪唑啉酮的合成与表征”是“综合创新实验”课程的一个实验。该实验以苯甲醛和硝基甲烷为原料，经Henry反应、Ritter反应、硝基的还原、氨基的保护以及酰胺的水解反应，制备4-苯基-2-咪唑啉酮。实验涉及柱层析、加热回流和萃取等操作。该实验包括5种经典的反应类型，合成方法比较成熟，结合有机化合物波谱解析，可以加深学生理解有机化合物官能团的转化及经典反应的反应机理，培养和提高学生有机合成的实验能力，激发和训练学生对有机合成及波谱解析的理解和应用。     

脉冲辐解研究3,4-亚甲二氧基苯甲醛的亲电性

报道了利用脉冲辐解技术研究3,4-亚甲二氧基苯甲醛亲电子性能的结果. 观测到3,4-亚甲二氧基苯甲醛与底物蒽醌-2-磺酸钠(AQS)之间在pH 7磷酸盐缓冲溶液中的电子转移过程, 检测到 3,4-亚甲二氧基苯甲醛与 3,4-亚甲二氧基苯甲醛之间电子转移反应的瞬态吸收谱, 为电子转移反应中电子给予体与受体之间电子转移的发生提供了直接的原初证据. 测定的3,4-亚甲二氧基苯甲醛的单电子还原电位值为-0.457 V.     

4-磺酸钾基邻苯二甲腈的合成

以4-硝基邻苯二甲腈为起始原料,经还原、重氮化、酰氯化、水解加碱中和得到酞菁水溶性前驱体4-磺酸钾基邻苯二甲腈,总收率22%,其结构由1H NMR,IR,MS和元素分析表征。     

2-氰基-3,4-二氢喹唑啉衍生物的合成

邻硝基苯甲醛与取代苯胺(1)或取代苄胺(2)进行还原氨化反应得N-(2-硝基苄基)取代苯胺(3)或N-(2-硝基苄基)取代苄胺(4);将3或4的硝基还原为氨基生成关键中间体N-(2-氨基苄基)取代苯胺(5)或N-(2-氨基苄基)取代苄胺(6);5或6分别与4,5-二氯-1,2,3-二噻唑氯化物进行缩合反应,合成了一系列新的2-氰基-3,4-二氢喹唑啉类衍生物,收率36%~72%,其结构经1H NMR和HR-MS确证。     

4′-{2-[5-(4-羧基苯基)呋喃基]}-2,2′:6′,2″-三联吡啶的合成——推荐一个大学有机化学实验

介绍一个面向大学高年级本科生的综合性有机化学实验——4′-{2-[5-(4-羧基苯基)呋喃基]}-2,2′:6′,2″-三联吡啶的合成与结构表征。以糠醛、对氨基苯甲酸为原料经低温条件下的偶联反应制备5-(4-羧基苯基)呋喃-2-甲醛,并以其和2-乙酰基吡啶为原料,在碱性条件下以氨水为氮源合成目标产物。通过熔点测定、红外光谱和核磁共振氢谱对其结构进行表征。该实验合成路线成熟,包括芳环偶联、α,β-不饱和酮的合成、Michael加成等内容,能达到多方面对学生进行锻炼之目的,是一个值得推荐的有机化学实验。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.