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1.
《Helvetica chimica acta》2017,100(8)
Unsymmetrical piperazines are key constituents of many pharmaceuticals. Given that the selective introduction of an aryl and alkyl motif onto the piperazine is not always straightforward, direct arylation and alkenylation of 1,4‐diaza‐bicyclo[2.2.2]octane would obviate the inefficiencies associated with the preparation of these target molecules. We have utilized alkyl halides, aryl or alkenyl triflates, and 1,4‐diaza‐bicyclo[2.2.2]octane for the synthesis of N‐alkyl‐N ′‐aryl or alkenylpiperazines. The optimum conditions are developed using CuCl, t‐BuOL i in NMP . Alkenyl triflates requires N ,N ′‐dimethylethylenediamine and higher temperature to afford the desired cross‐coupled product. Substrates bearing electron‐deficient and electron‐rich groups were successfully coupled under the optimum reaction conditions. 相似文献
2.
Cristóbal García Karina Cabezas Santi Nonell Javier Morales Germán Günther Nancy Pizarro 《Photochemistry and photobiology》2014,90(1):73-78
The electronic nature of substituents attached to the 4‐aryl moiety of 1,4‐dihydropyridines strongly affects the photophysical and photochemical behavior of these family of compounds. The presence of an electron donor substituent on the 4‐aryl moiety (or the absence of electron‐withdrawing ones) modifies the luminescence lifetimes (τ < 100 ps) and diminishes the photodecomposition quantum yields. For electron‐withdrawing substituents, the photodegradation quantum yield is affected by the media, changing more than two orders of magnitude as the polarity is increased. Studies in micellar media allow us to conclude that 4‐aryl‐1,4‐dihydropyridines are located near to the interface; however, the surface charge of micelles has no effect on the photodegradation rate constant or the photoproducts profile. The main conclusion of this work is that the photolability of 4‐aryl‐1,4‐dihydropyridines can be significantly reduced by the incorporation of antioxidant moieties. 相似文献
3.
《化学:亚洲杂志》2017,12(21):2819-2826
Mono‐, di‐, tri‐, and tetraarylated thieno[3,2‐b ]thiophenes were synthesized by direct site‐selective Pd‐catalyzed C−H activation reactions with various aryl bromides in the presence of a phosphine‐free Pd(OAc)2/KOAc catalyst system in N ,N ‐dimethylacetamide (DMAc). The arylation of 2‐arylthieno[3,2‐b ]thiophene took place at the C3 position if the 2‐aryl substituents possessed electron‐withdrawing groups and at the C5 position if they were bulky and possessed electron‐donating groups. 相似文献
4.
A direct synthetic route for the C―S coupling of aryl halides with thiophenols is described. This method is tolerant to electron‐withdrawing and electron‐donating functional groups and also to the presence of functional groups in the ortho position of the aryl iodide or thiophenol. Aryl iodides are coupled with thiophenols without affecting the other functionalities present in the aryl ring. These reactions follow second‐order kinetics. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
5.
Access to Air‐Stable 1,3‐Diphosphacyclobutane‐2,4‐diyls by an Arylation Reaction with Arynes 下载免费PDF全文
Yasuhiro Ueta Prof. Dr. Koichi Mikami Prof. Dr. Shigekazu Ito 《Angewandte Chemie (International ed. in English)》2016,55(26):7525-7529
Tuning of the physicochemical properties of the 1,3‐diphosphacyclobutane‐2,4‐diyl unit is attractive in view of materials applications. The use of arynes is shown to be effective for installing relatively electron rich aryl substituents into the open‐shell singlet P‐heterocyclic system. Treatment of the sterically encumbered 1,3‐diphosphacyclobuten‐4‐yl anion with ortho‐silylated aryl triflates in the presence of fluoride under appropriate conditions afforded the corresponding 1‐aryl 1,3‐diphosphacyclobutane‐2,4‐diyls. The air‐stable open‐shell singlet P‐heterocycles exhibit considerable electron‐donating character, and the aromatic substituent influences the open‐shell character, which is thought to be related to the property of p‐type semiconductivity. The P‐arylated 1,3‐diphosphacyclobutane‐2,4‐diyl systems can be further utilized as detectors of hydrogen fluoride (HF), which causes a remarkable change in their photoabsorption properties. 相似文献
6.
Prof. Dr. Yutaka Matsuo Hiromi Oyama Dr. Iwao Soga Dr. Toshihiro Okamoto Dr. Hideyuki Tanaka Dr. Akinori Saeki Prof. Dr. Shu Seki Prof. Dr. Eiichi Nakamura 《化学:亚洲杂志》2013,8(1):121-128
The efficient nucleophilic addition of aryl Grignard reagents (aryl=4‐MeOC6H4, 4‐Me2NC6H4, Ph, 4‐CF3C6H4, and thienyl) to C60 in the presence of DMSO produced 1,2‐arylhydro[60]fullerenes after acid treatment. The reactions of the anions of these arylhydro[60]fullerenes with either dimethylphenylsilylmethyl iodide or dimethyl(2‐isopropoxyphenyl)silylmethyl iodide yielded the target compounds, 1‐aryl‐4‐silylmethyl[60]fullerenes. The properties and structures of these 1‐aryl‐4‐silylmethyl[60]fullerenes (aryl=4‐MeOC6H4, thienyl) were examined by electrochemical studies, X‐ray crystallography, flash‐photolysis time‐resolved microwave‐conductivity (FP‐TRMC) measurements, and electron‐mobility measurements by using a space‐charge‐limited current (SCLC) model. Organic photovoltaic devices with a polymer‐based bulk heterojunction structure and small‐molecule‐based p–n and p–i–n heterojunction configurations were fabricated by using 1‐aryl‐4‐silylmethyl[60]fullerenes as an electron acceptor. The most efficient device exhibited a power‐conversion efficiency of 3.4 % (short‐circuit current density: 8.1 mA/ cm2, open‐circuit voltage: 0.69 V, fill factor: 0.59). 相似文献
7.
Dr. Mingsheng Xie Dr. Lili Lin Prof. Dr. Xiaoming Feng 《Chemical record (New York, N.Y.)》2017,17(12):1184-1202
In this review, the recent developments in catalytic asymmetric inverse‐electron‐demand hetero‐Diels−Alder reaction, which is recognized as one of the most powerful routes to construct highly functionalized and enantioenriched six‐membered heterocycles, are described. The article is organized on the basis of different kinds of electron‐deficient heterodienes, including α,β‐unsaturated ketones/aldehydes, o‐benzoquinones, α,β‐unsaturated imines, N‐aryl imines, o‐benzoqinone imides, and other aza‐olefins. 相似文献
8.
Organocatalytic Asymmetric Friedel–Crafts Reaction of Sesamol with Isatins: Access to Biologically Relevant 3‐Aryl‐3‐hydroxy‐2‐oxindoles 下载免费PDF全文
Dr. Akshay Kumar Jasneet Kaur Dr. Pankaj Chauhan Prof. Dr. Swapandeep Singh Chimni 《化学:亚洲杂志》2014,9(5):1305-1310
The Friedel–Crafts reaction of electron‐rich phenols with isatins was developed by employing bifunctional thiourea–tertiary amine organocatalysts. Cinchona alkaloid derived thiourea epiCDT‐ 3 a efficiently catalyzed the Friedel–Crafts‐type addition of phenols to isatin derivatives to provide 3‐aryl‐3‐hydroxy‐2‐oxindoles 7 and 9 in good yield (80–95 %) with good enantiomeric excess (83–94 %). Friedel–Crafts adduct 7 t was subjected to a copper(I)‐catalyzed azide–alkyne cycloaddition to obtain biologically important 3‐aryl‐3‐hydroxy‐2‐oxindole 11 in good enantiomeric excess and having a 1,2,3‐triazole moiety. 相似文献
9.
A series of N‐aryl 2‐alkenamides were produced efficiently by treating N‐aryl 3‐(phenylsulfonyl)‐propanamides with potassium tert‐butoxide in THF at 0°C. With out isolation, it was further treated with an additional equivalent of potassium tert‐butoxide and allyl bromide to give N‐allyl N‐aryl 2‐alkenamides in one pot in good yields. Followed by a ring‐closing metathesis reaction, these N‐allyl N‐aryl 2‐alkenamides were respectively converted into corresponding N‐aryl α,β‐unsaturated γ‐lactams in moderate yields. 相似文献
10.
Nickel‐Catalyzed Synthesis of N‐Aryl‐1,2‐dihydropyridines by [2+2+2] Cycloaddition of Imines with Alkynes through T‐Shaped 14‐Electron Aza‐Nickelacycle Key Intermediates 下载免费PDF全文
Dr. Yoichi Hoshimoto Tomoya Ohata Dr. Masato Ohashi Prof. Dr. Sensuke Ogoshi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(14):4105-4110
Despite there being a straightforward approach for the synthesis of 1,2‐dihydropyridines, the transition‐metal‐catalyzed [2+2+2] cycloaddition reaction of imines with alkynes has been achieved only with imines containing an N‐sulfonyl or ‐pyridyl group. Considering the importance of 1,2‐dihydropyridines as useful intermediates in the preparation of a wide range of valuable organic molecules, it would be very worthwhile to provide novel strategies to expand the scope of imines. Herein we report a successful expansion of the scope of imines in nickel‐catalyzed [2+2+2] cycloaddition reactions with alkynes. In the presence of a nickel(0)/PCy3 catalyst, a reaction with N‐benzylidene‐P,P‐diphenylphosphinic amide was developed. Moreover, an application of N‐aryl imines to the reaction was also achieved by adopting N‐heterocyclic carbene ligands. The isolation of an (η2‐N‐aryl imine)nickel(0) complex containing a 14‐electron nickel(0) center and a T‐shaped 14‐electron five‐membered aza‐nickelacycle is shown. These would be considered as key intermediates of the reaction. The structure of these complexes was unambiguously determined by NMR spectroscopy and X‐ray analyses. 相似文献
11.
Clve D. Mboyi Delphine Vivier Ahmad Daher Paul Fleurat‐Lessard Hlne Cattey Charles H. Devillers Claire Bernhard Franck Denat Julien Roger Jean‐Cyrille Hierso 《Angewandte Chemie (International ed. in English)》2020,59(3):1149-1154
Click chemistry at a tetrazine core is useful for bioorthogonal labeling and crosslinking. Introduced here are two new classes of doubly clickable s‐aryl tetrazines synthesized by Cu‐catalyzed cross‐coupling. Homocoupling of o‐brominated s‐aryl tetrazines leads to bis(tetrazine)s structurally characterized by tetrazine cores arranged face‐to‐face. [N]8 π‐stacking interactions are essential to the conformation. Upon inverse electron demand Diels–Alder (iEDDA) cycloaddition, the bis(tetrazine)s produce a unique staple structure. The o‐azidation of s‐aryl tetrazines introduces a second proximal intermolecular clickable function that leads to double click chemistry opportunities. The stepwise introduction of fluorophores and then iEDDA cycloaddition, including bioconjugation to antibodies, was achieved on this class of tetrazines. This method extends to (thio)etherification, phosphination, trifluoromethylation and the introduction of various bioactive nitrogen‐based heterocycles. 相似文献
12.
Palladium 2‐mercapto‐N‐propylacetamide complex anchored onto MCM‐41 as efficient and reusable nanocatalyst for Suzuki,Stille and Heck reactions and amination of aryl halides 下载免费PDF全文
Mohsen Nikoorazm Arash Ghorbani‐Choghamarani Nourolah Noori Bahman Tahmasbi 《应用有机金属化学》2016,30(10):843-851
A palladium 2‐mercapto‐N‐propylacetamide complex supported on functionalized MCM‐41 was prepared by a post‐grafting method and considered as an efficient catalyst for C? C cross‐coupling reactions between various aryl halides and sodium tetraphenylborate, phenylboronic acid, triphenyltin chloride or alkenes. Also, this catalyst shows good reactivity towards amination of aryl halides. This nanocatalyst was characterized using thermogravimetric analysis, X‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, inductively coupled plasma and transmission electron microscopy techniques. Further results indicated that the heterogeneous catalyst could be recovered easily and reused several times without any loss of its catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
13.
Amritpal Kaur Avneet Pal Kaur Poonam Gautam Deepika Gautam Ram Pal Chaudhary 《Journal of heterocyclic chemistry》2019,56(8):2105-2110
Alkanediyl‐bis‐2‐aryl‐thiazolidin‐4‐one and alkanediyl‐bis‐2‐aryl‐1,3‐thiazinan‐4‐one derivatives have been congregated in a single step reaction of diaminoalkanes, aryl aldehydes, and sulfanyl acids in the presence of coupling agent N,N′‐dicyclohexylcarbodiimide under ultrasonic conditions. This method of constructing 4‐keto derivatives of thiazolidine and thiazinane is quick and clean besides yielding the products in quantitative yields. The spectral techniques corroborated the structures of the isolated products. Biological assay of the synthesized products has also been reported. 相似文献
14.
《Journal of heterocyclic chemistry》2017,54(4):2258-2265
The present study emphasizes on the dealklylation of 3‐aryl‐5‐alkyl‐2‐oxo‐Δ4‐1,3,4‐oxadiazoles when reacted with formamide resulting in the formation of 2‐aryl‐2H‐1,2,4‐triazol‐3(4H )‐ones as major product. Subsequent reactions of 2‐aryl‐2H‐1,2,4‐triazol‐3(4H )‐one gave triazolo[3,4‐b ][1,3,4]thiadiazoles and triazolo[3,4‐b ][1,3,4]thiadiazines derivatives incorporated with 1,2,4‐triazol‐3‐one. 相似文献
15.
Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation 下载免费PDF全文
One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO3 have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism. 相似文献
16.
A general synthesis of 1‐aryl‐1‐H‐indazoles from o‐halogenated aryl aldehydes or ketones and aryl hydrazines was described. This protocol included an intermolecular condensation and a ligand‐free copper‐catalyzed intramolecular Ullmann‐type coupling reaction. This method was applied to a wide range of substrates to produce the indazole products in good yields. 相似文献
17.
3‐Alkyl/aryl‐3‐ureido‐1H,3H‐quinoline‐2,4‐diones ( 2 ) and 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) react in boiling concentrated HCl to give 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ). The same compounds were prepared by the same procedure from 2‐alkyl/aryl‐3‐ureido‐1H‐indoles ( 4 ), which were obtained from the reaction of 3‐alkyl/aryl‐3‐aminoquinoline‐2,4(1H,3H)‐diones ( 1 ) with 1,3‐diphenylurea or by the transformation of 3a‐alkyl/aryl‐9b‐hydroxy‐3,3a,5,9b‐tetrahydro‐1H‐imidazo[4,5‐c]quinoline‐2,4‐diones ( 3 ) and 5‐alkyl/aryl‐4‐(2‐aminophenyl)‐1,3‐dihydro‐2H‐imidazol‐2‐ones ( 6 ) in boiling AcOH. The latter were converted into 1,3‐bis[2‐(2‐oxo‐2,3‐dihydro‐1H‐imidazol‐4‐yl)phenyl]ureas ( 5 ) by treatment with triphosgene. All compounds were characterized by 1H‐ and 13C‐NMR and IR spectroscopy, as well as atmospheric pressure chemical‐ionisation mass spectra. 相似文献
18.
A Facile Synthesis of Some New 1‐Benzothiazolyl‐3‐aryl/Hetaryl‐5‐(3‐aryl‐1‐phenyl‐4‐pyrazolyl) Pyrazoles and Their Antimicrobial Activity 下载免费PDF全文
Sushma Singh Vijaykiran Punia Chetan Sharma K. R. Aneja Om Prakash Rashmi Pundeer 《Journal of heterocyclic chemistry》2015,52(6):1817-1822
Some new derivatives of 1‐benzothiazolyl‐3‐aryl/hetaryl‐5‐(3‐aryl‐1‐phenyl‐4‐pyrazolyl) pyrazoles were synthesized by the cyclocondensation of 1‐aryl/hetaryl‐3‐(3‐aryl‐1‐phenyl‐1H‐pyrazole‐4‐yl)prop‐2‐en‐1‐ones (pyrazolyl chalcones) and 6‐substituted‐2‐hydrazinobenzothiazoles. 相似文献
19.
Rafael Germano Santana Derisvaldo Rosa Paiva Roberto da Silva Gomes Adriana Karla C. A. Reis 《Magnetic resonance in chemistry : MRC》2013,51(5):316-319
The complete assignment of the 1H and 13C NMR spectra of various 2‐acetamido‐3‐mercapto‐3‐methyl‐N‐aryl‐butanamides and 2‐acetamide‐3‐methyl‐3‐nitrososulfanyl‐N‐aryl‐butanamides with p‐methoxy, o‐chloro and m‐chloro substituents is reported. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
20.
Room‐Temperature Amination of Deactivated Aniline and Aryl Halide Partners with Carbonate Base Using a Pd‐PEPPSI‐IPentCl‐ o‐Picoline Catalyst 下载免费PDF全文
Matthew Pompeo Jennifer L. Farmer Dr. Robert D. J. Froese Prof. Michael G. Organ 《Angewandte Chemie (International ed. in English)》2014,53(12):3223-3226
Current state‐of‐the‐art protocols for the coupling of unreactive amines (e.g., electron‐poor anilines) with deactivated oxidative‐addition partners (e.g., electron‐rich and/or hindered aryl chlorides) involve strong heating (usually >100 °C) and/or tert‐butoxide base, and even then not all couplings are successful. The aggressive base tert‐butoxide reacts with and in many instances destroys the typical functional groups that are necessary for the function of most organic molecules, such as carbonyl groups, esters, nitriles, amides, alcohols, and amines. The new catalyst described herein, Pd‐PEPPSI‐IPentCl‐o‐picoline, is able to aminate profoundly deactivated coupling partners when using only carbonate base at room temperature. 相似文献