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1.
Silver‐Catalyzed Isocyanide–Isocyanide [3+2] Cross‐Cycloaddition Involving 1,2‐Group Migration: Efficient Synthesis of Trisubstituted lmidazoles 下载免费PDF全文
Hongwei Wang Dr. Rapolu Kiran Kumar Yang Yu Dr. Lin Zhang Zhaohong Liu Dr. Peiqiu Liao Prof. Xihe Bi 《化学:亚洲杂志》2016,11(20):2841-2845
Imidazole ring is an important five‐membered aromatic heterocycle that is widely present in natural products and synthetic molecules. The isocyanide–isocyanide [3+2] cross‐cycloaddition reaction constitutes a straightforward method to access imidazoles starting from the easily available chemicals. So far, only three successive reports are known and all lead to the formation of 1,4‐disubstituted imidazoles. Here, we report the first isocyanide–isocyanide [3+2] cross‐cycloaddition reaction allowing for the formation of 1,4,5‐trisubstituted imidazoles under silver catalysis. An unexpected 1,2‐migration of sulfonyl, alkoxycaybonyl, and carbamoyl groups took place during the cyclization process that is responsible for the formation of trisubstituted imidazoles. This report displayed a mechanistically novel synthetic method toward a variety of imidazole derivatives, which are otherwise difficult to access by conventional methods. 相似文献
2.
Cover Picture: Silver‐Catalyzed Isocyanide–Isocyanide [3+2] Cross‐Cycloaddition Involving 1,2‐Group Migration: Efficient Synthesis of Trisubstituted lmidazoles (Chem. Asian J. 20/2016) 下载免费PDF全文
Hongwei Wang Dr. Rapolu Kiran Kumar Yang Yu Dr. Lin Zhang Zhaohong Liu Dr. Peiqiu Liao Prof. Xihe Bi 《化学:亚洲杂志》2016,11(20):2808-2808
3.
An efficient synthesis of 3,6-disubstituted-4-aroyl-2-pyrones in a single-step reaction through Michael addition of 1,2-diaroylacetylenes with active methylene compounds in the presence of NaH in dimethylsulfoxide at room temperature is reported. The structures have been confirmed by spectral data analyses.
4.
Synthesis of benzimidazoles by copper‐catalyzed aerobic oxidative domino reaction of 1,2‐diaminoarenes and arylmethyl halides 下载免费PDF全文
Arylmethyl halides are readily synthesized via halogenation from the basic raw materials, even in green processes. They are used to replace their downstream products to prepare medicinally important 2‐aryl benzimidazoles. CuBr‐catalyzed synthesis of 2‐aryl benzimidazoles from arylmethyl halides and 1,2‐diaminoarenes via a one‐pot domino reaction is developed. This new synthetic method is simple, practical and cost saving, and tolerates wide functional groups. A mechanism of CuBr‐catalyzed aerobic oxidative domino reaction via a one‐pot four‐step process is proposed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
5.
合成了2种聚合前驱体邻苯二丙烯酸酯(o-PDA)和2-甲氧基苯丙烯酸酯(2-MOPA), 分别通过与丙烯酸(AA)自由基共聚得到邻苯二丙烯酸酯-丙烯酸共聚物(O1)和2-甲氧基苯丙烯酸酯-丙烯酸共聚物(O2). 产物邻苯二酚(o-DHB)-O1(质量比1∶1)和1-羟基-2-甲氧基苯(HMOB)-O2(质量比1∶1)分别在乙腈/二氯甲烷-三氟化硼乙醚体系中直接阳极氧化聚合获得交联网状共聚物P1和P2. P1和P2均可溶于DMSO, 而难溶于ACN, DCM和THF等有机溶剂. 通过UV-Vis, FTIR和 1H NMR对交联共聚物膜的结构进行了表征. AA的引入不仅可以增加链的柔韧性, 而且提高了共聚物的力学性能. 而o-DHB/ HMOB的引入极大地减弱了单体的聚合位阻, 实现了单体的二次聚合, 同时也增强了单体及聚合物的电化学活性. 荧光光谱显示, 得到的2种交联共聚物膜分别在415和487 nm处有较强的发射峰, 表明共聚物仍具有良好的蓝色发光性能, 且聚丙烯酸结构的引入并没有对聚邻苯二酚(Po-DHB)和聚(1-羟基-2-甲氧基苯)(PHMOB)产生较大的荧光猝灭作用. 热重分析曲线(TGA)表明2种交联共聚物膜均具有较高的热稳定性. 相似文献
6.
Francisco Palacios Domitila Aparicio Yago López Jesús M. de los Santos 《Tetrahedron letters》2004,45(22):4345-4348
Achiral and chiral 1,2-diaza-1,3-butadienes derived from phosphine oxides and phosphonates are obtained from hydrazonoalkyl-phosphine oxides and -phosphonates. Michael addition (1,4-addition) of ammonia, aminoesters and aminoalcohols to these azo-alkenes gives functionalized α-amino-phosphine oxides and -phosphonates. 相似文献
7.
Anastasiya V. Igushkina Alexander A. Golovanov Aleksander V. Vasilyev 《Molecules (Basel, Switzerland)》2022,27(4)
Reaction of linear conjugated enynones, 1,5-diarylpent-2-en-4-yn-1-ones [Ar1C≡CCH=CHC(=O)Ar2], with 3-oxo-3-phenylpropanenitrile (NCCH2COPh) in the presence of sodium methoxide MeONa as a base in MeOH at room temperature for 4–26 h affords polyfunctional δ-diketones as a product of regioselective Michael addition to the double carbon–carbon bond of starting enynones. The δ-diketones have been formed as mixtures of two diastereomers in a ratio of 2.5:1 in good general yields of 53–98%. A synthetic potential of the obtained δ-diketones has been demonstrated by heterocyclization with hydrazine into substututed 5,6-dihydro-4H-1,2-diazepine. 相似文献
8.
Efficient Synthesis of Chiral Trisubstituted 1,2‐Allenyl Ketones by Catalytic Asymmetric Conjugate Addition of Malonic Esters to Enynes 下载免费PDF全文
Qian Yao Yuting Liao Dr. Lili Lin Xiaobin Lin Jie Ji Prof. Dr. Xiaohua Liu Prof. Dr. Xiaoming Feng 《Angewandte Chemie (International ed. in English)》2016,55(5):1859-1863
An N,N′‐dioxide/scandium(III) complex catalyzed, highly efficient conjugate addition of malonic esters to enynes is described. A range of trisubstituted 1,2‐allenyl ketones were obtained in high yields (up to 99 %) with good d.r. (up to 95/5) and excellent ee values (97 %–99 %). Moreover, the products could be easily transformed into chiral furan and 5‐hydroxypyrazoline derivatives, both of which are important skeletons of many biologically active compounds and pharmacologicals. 相似文献
9.
Edvard E. Nifantyev Tatyana S. Kukhareva Dmitriy V. Khodarev Larisa K. Vasyanina 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2733-2743
Methods for the synthesis of major monosaccharide hydrophosphoryl derivatives have been developed with the phosphorylation of 1,2:5,6-di-O-isopropylidene-α -D-glucofuranose (diacetoneglucose) as an example. The study of their chemical transformations has been launched. 相似文献
10.
Trifluoromethoxylation of Arenes: Synthesis of ortho‐Trifluoromethoxylated Aniline Derivatives by OCF3 Migration 下载免费PDF全文
Katarzyna N. Hojczyk Dr. Pengju Feng Chengbo Zhan Prof. Ming‐Yu Ngai 《Angewandte Chemie (International ed. in English)》2014,53(52):14559-14563
Aryl trifluoromethoxylation by a two‐step sequence of O‐trifluoromethylation of N‐aryl‐N‐hydroxylamine derivatives and intramolecular OCF3 migration is presented. This protocol allows easy access to a wide range of synthetically useful ortho‐OCF3 aniline derivatives. In addition, it utilizes bench‐stable reagents, is operationally simple, shows high functional‐group tolerance, and is amenable to gram‐scale as well as one‐pot synthesis. A reaction mechanism of a heterolytic cleavage of the N? OCF3 bond followed by recombination of the resulting nitrenium ion and trifluoromethoxide is proposed for the OCF3‐migration reaction. 相似文献
11.
Reaction of salicylaldehydes with tetraethyl ester of methylenebisphosphonic acid, under Knoevenagel reaction conditions, gives the corresponding 1,2-benzoxaphosphorin-3-phosphonates 5 in good yields. The [3+2] regio- and stereoselective cycloaddition of 5a and 5b with ethyl diazoacetate gives two P-4 epimers of the corresponding pyrazoline bisphosphonate tetraethyl esters 9 and 10. Analogously, ethyl diazoacetate reacts with 1 and 2 to give the expected pyrazolines 6-8. The structures of the new compounds are revealed and confirmed by analytical, spectroscopic data and X-ray crystallographic analysis. 相似文献
12.
Ali Ramazani Aram Rezaei Amir Tofangchi Mahyari Morteza Rouhani Mehdi Khoobi 《Helvetica chimica acta》2010,93(10):2033-2036
The zwitterion, formed from the reaction of an alkyl isocyanide and a dialkyl acetylenedicarboxylate, reacts with phenacyl halides in H2O to produce γ‐iminolactone derivatives in high yields. H2O helps to avoid the use of highly toxic and environmentally unfavorable solvents for this conversion. 相似文献
13.
14.
无溶剂条件下,用氨基磺酸催化芳香醛,2-氨基苯并咪唑和β-二羰基化合物的三组分反应,简单而方便地得到了苯并[4,5]咪唑并[1,2-a]嘧啶类衍生物.该法具有产率高,成本低廉,环境友好,适应性广简捷方便等优点. 相似文献
15.
Orthogonally protected 1,2-diaminopropanoic acids (DAPs) have been synthesised in good yields by the ring-opening of 3-unsubstituted N-activated aziridine 2-carboxylates with para-methoxybenzylamine. The choice of both the N-activating group and ester alkyl group had a significant influence on the ratio of attack at the α or β positions of the aziridine. However, the regiochemical outcome is not predictable. 相似文献
16.
A new synthetic approach to 2,3-dihydro-4H-1,3-thiazine derivatives based upon reductive rearrangement of 1,2-dithiole-3-ylidene thiones has been developed. In turn, the 1,2-dithiole derivatives were prepared by an efficient ring-opening-closing process of 2-alkylidene-4-oxothiazolidines, induced in the presence of Lawesson's reagent by intramolecular non-bonded 1,5-type S?O interactions in the 4-oxothiazolidine precursors. 相似文献
17.
Regiodivergent Addition of Phenols to Allylic Oxides: Control of 1,2‐ and 1,4‐Additions for Cyclitol Synthesis 下载免费PDF全文
Matthew J. Moschitto David N. Vaccarello Prof. Dr. Chad A. Lewis 《Angewandte Chemie (International ed. in English)》2015,54(7):2142-2145
Control of 1,2‐ and 1,4‐addition of substituted phenols to allylic oxides is achieved by intercepting palladium π‐allyl complexes. The interconversion of palladium complexes results in the total synthesis of MK 7607, cyathiformine B type, streptol, and a new cyclitol. 相似文献
18.
Gold(I)‐Catalyzed Furan‐yne Cyclizations Involving 1,2‐Rearrangement: Efficient Synthesis of Functionalized 1‐Naphthols and Its Application to the Synthesis of Wailupemycin G 下载免费PDF全文
Dr. Yifeng Chen Dr. Lu Wang Ning Sun Xin Xie Dr. Xiaobo Zhou Haoyi Chen Prof. Yuxue Li Prof. Yuanhong Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(38):12015-12019
Gold‐catalyzed cascade cyclization/1,2‐rearrangement of 1‐(2‐furanyl)phenyl propargyl alcohols has been developed, which provides a rapid and efficient access to multisubstituted 1‐naphthols bearing an enal or enone moiety with high stereoselectivity. The (Z)‐ or (E)‐stereochemistry can be easily controlled by choosing protected‐ or non‐protected substrates. The utility of the methodology has been illustrated in the first total synthesis of wailupemycin G. 相似文献
19.
Triflic Acid Mediated Cascade Cyclization of Aryldiynes for the Synthesis of Indeno[1,2‐c]chromenes: Application to Dye‐Sensitized Solar Cells 下载免费PDF全文
Hua Jiang Dr. Giovanni Ferrara Xuan Zhang Kazuaki Oniwa Dr. Ashraful Islam Dr. Liyuan Han Dr. Ying‐Ji Sun Ming Bao Dr. Naoki Asao Dr. Yoshinori Yamamoto Dr. Tienan Jin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):4065-4070
A new triflic acid (TfOH)‐mediated cascade cyclization of ortho‐anisole‐substituted aryldiynes is described for the construction of indeno[1,2‐c]chromenes. The cascade cyclization proceeds through an unusual TfOH‐induced alkyne‐alkyne cyclization followed by nucleophilic attack of the methoxy group on the benzylidene cation, which is completely different to the cyclization of ortho‐aniline‐ or ortho‐thioanisole‐substituted aryldiynes. A new class of organic dyes with the indeno[1,2‐c]chromene framework as both donor and π‐linker were synthesized. These compounds exhibit high photovoltaic performances in dye‐ sensitized solar cells (DSCs). 相似文献