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镧系金属用于有机反应的研究:无水NdCl3/萘锂体系与酮及异… 总被引:1,自引:0,他引:1
报道了无水NdCl3/萘锂体系与二苯酮、α、β-不饱和羰基化合物、异氰酸酯及异硫氰酸酯的反应,研究发现,无水NdCl3/萘锂体系可引发α、β-不饱和羰基化合物发生新奇的二聚环化反应得到互为异构体的环戊醇衍生物,与异氰酸酯或异硫氰酸酯反应则得到较高产率的相应的原偶联产物草酰妥或硫代草酰胺,而在某些配体存在下,无水NdCl3/萘锂体系与二苯酮作用时,有别于单纯的NdCl3/萘锂体系,反应选择性发生了明 相似文献
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2—羟基2‘烷氧基—1,1’—联萘化合物的^1HMNR研究 总被引:1,自引:1,他引:0
研究了2-羟基-2'-异丙氧基-1,1-联萘(3)等联萘化合物^1H NMR谱或COSY谱,此类化合物因2及2'位取代基不同,两个萘环上同位质子不再等价,萘环质子峰增至12组。化合物3^1HNMR谱峰的归属表明,萘环环电流各向异性对另一萘环质子的屏蔽作用与作者早期研究结果一致。2(或2')位取代基上的质子的化学位移也与另一萘环平面相对位置有关。 相似文献
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手性1,1‘—联二萘化学的进展 总被引:7,自引:0,他引:7
引言萘是一个芳香烃,没有手性,但当两个萘环在1位处相连,而且在2位处引入两个基团(x)后,就成了一个具有官能团的手性化合物。它同时具有三个结构条件:1.分子的轴不对称;2.刚性和韧性;3.官能团。两个萘环的体积大,其空间阻碍具有刚性,但两个环之间,由 相似文献
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螯合树脂研究——ⅩⅥ.以壳聚糖为母体的含硫、氮螯合树脂的合成及其吸附性能 总被引:13,自引:2,他引:13
壳聚糖与环硫氯丙烷反应合成了一系列含S和N的交联型螫合树脂。这类树脂对贵金属离子如:金、银、钯、铂等具有优良的吸附性能。 相似文献
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1,8—萘酐和1,8—萘酰亚胺中硝基和卤素基团的亲核取代反应 总被引:2,自引:0,他引:2
研究了1,8-萘酐和1,8-萘酰亚胺萘环上硝基和卤素原子的亲核取代反应,讨论了影响亲核取代反应的因素,根据2,4-二硝基苯酚与脂胺肪的亲核取代机理,提出了4-硝基-1,8-萘酐及4-硝基-1,8-萘酰亚胺与脂肪胺发生亲核取代反应可能的反应机理。 相似文献
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报道了无水NdCl3/萘锂体系与二苯酮、α,β-不饱和羰基化合物、异氰酸酯及异硫氰酸酯的反应。研究发现:无水NdCl3/萘锂体系可引发α,β-不饱和羰基化合物发生新奇的二聚环化反应得到互为异构体的环戊醇衍生物,与异氰酸酯或异硫氰酸酯反应则得到较高产率的相应的还原偶联产物草酰胺或硫代草酰胺。而在某些配体存在下,无水NdC13/萘锂体系与二苯酮作用时,有别于单纯的NdCl3/萘锂体系,反应选择性发生了明显的改变,主要得到二苯甲醇。 相似文献
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萘在高温煤焦油中的含量可达10%以上,以萘为原料进行催化缩聚是制备中间相沥青和功能炭材料的有效途径。本研究以无水AlCl3为催化剂,系统研究了萘在不同温度(90-170℃)及AlCl3与萘物质的量比(1∶100-30∶100)条件下的常压聚合过程。结果表明,当温度低于110℃时,缩聚产物主要由多联三环化合物构成,重质产物仅占29.5%;温度为150℃时,缩聚产物以四至五环迫位芳香缩合物为主,中质组分含量保持在50%;温度为170℃时,缩聚产物中存在大量六环芳香核,原料转化率高达90.7%,而且产物具有良好的流动性及在THF中的溶解性,有利于高温热缩聚及后续石墨化工艺。本研究在提出“齐聚-热解-稠环化”反应机理基础上,考察了催化萘聚合产物的结构与组成:当AlCl3与萘物质的量比为1∶100时,对萘短链齐聚进行模拟,可得二至七级萘齐聚物,而将AlCl3与萘物质的量比提升至10∶100时,萘受AlCl3催化热解可产生乙炔和甲基萘。该研究阐明了萘沥青前驱体的形成机理,为进一步萘催化缩聚... 相似文献
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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%. 相似文献
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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. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%). 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones. 相似文献
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In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates. 相似文献