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1.
A simple and efficient 2N2O–Cu(II) complex as a catalyst for N‐arylation of imidazoles in water
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Four inexpensive and air‐ and moisture‐stable 2N2O–Cu complexes were synthesized, one of which proved to exhibit good catalytic activity for the N‐arylation of imidazoles in water. A variety of aryl iodides and aryl bromides underwent coupling with imidazoles promoted by the catalytic system with moderate to excellent yields. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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A novel strategy for the Pictet-Spengler reaction is reported. Our strategy involves reaction of arylamines, linked to the N-1 of disubstituted imidazoles, with aldehydes in the presence of p-TsOH. The iminium ion generated in situ undergoes C-C bond formation with the C-5 of the imidazoles to furnish triazabenzoazulenes as a novel heterosystem. Our strategy differs from conventional Pictet-Spengler reaction since the latter utilizes only aliphatic amines in which the amine functionality is linked to a C instead of N of the activated aromatic moiety. 相似文献
4.
The completely N(1)-selective Pd-catalyzed arylation of unsymmetric imidazoles with aryl halides and triflates is described. This study showed that imidazoles have a strong inhibitory effect on the in situ formation of the catalytically active Pd(0)-ligand complex. The efficacy of the N-arylation reaction was improved drastically by the use of a preactivated solution of Pd(2)(dba)(3) and L1. From these findings, it is clear that while imidazoles can prevent binding of L1 to Pd, once the ligand is bound to the metal, these heterocycles do not displace it. The utility of the present catalytic system was demonstrated by the regioselective synthesis of the clinically important tyrosine kinase inhibitor nilotinib. 相似文献
5.
Antonio de la Hoz Ángel Díaz-Ortiz Mónica Moral José Elguero Matías L. Rodríguez 《Tetrahedron》2006,62(25):5868-5874
A series of 2-imidazolines and imidazoles has been synthesized using green synthetic methodologies. The preparation of 2-imidazolines was performed by cyclization of nitriles with ethylenediamine. The use of microwave irradiation in solvent-free conditions enabled 2-imidazolines to be obtained in high yields within short reaction times. Aromatization of imidazoles was performed under microwave irradiation in toluene and using Magtrieve™ as the oxidant. The X-ray structures for five of these derivatives are provided. In all cases, the molecules are assembled into chains through N-H?N hydrogen bonds. 相似文献
6.
Marchenko AP Koidan HN Huryeva AN Zarudnitskii EV Yurchenko AA Kostyuk AN 《The Journal of organic chemistry》2010,75(21):7141-7145
It has been experimentally proven that the reaction of 1- or 1,2-disubstituted imidazoles with diorganylphosphorus(III) halides proceeds via initial formation of N-phosporylated imidazolium salts. Treatment of these salts with strong bases results in phosphorylation of the parent imidazoles at the 2- or 5-positions, correspondingly. In a previous case, imidazol-2-ylidenes are formed as intermediates. With both N1 and N3 atoms bearing sterically demanding or/and π-donating groups, deprotonation of 1,3-disubstituted imidazolium salts with NaN(SiMe(3))(2) afforded new stable N-phosphorus-substituted Arduengo-type carbenes. 相似文献
7.
One-pot multi-component synthesis of N,N′-alkylidene bisamides, 2,4,5-trisubstituted imidazoles and 1,2,4,5-tetrasubstituted imidazoles in the presence of catalytic material heteropoly-11-tungsto-1-vanadophosphoric acid (HPV) supported on activated natural clay for about 20% (HPVAC-20) under solvent-free reaction condition have been achieved. Green heterogeneous reaction condition, simple workup procedure, short reaction time, high yield of products, and reusability of the catalyst are the advantages of this protocol. 相似文献
8.
Immobilized copper(Ⅱ) in organic-inorganic hybrid materials catalyzed Ar-N coupling of arylboronic acids with imidazoles has been developed. Arylboronic acids reacted with imidazoles smoothly in the presence of a 3-(2-aminoethylamino)propyl functionalized silica gel immobilized copper(Ⅱ) catalyst (10 mol%) in methanol without any additives and bases. The reactions generated the corresponding cross-coupling products in good yields. Furthermore, silica-supported copper can be recovered and recycled by a simple filtration procedure and used for five consecutive trials without decreases in activity. 相似文献
9.
Jayabharathi J Thanikachalam V Srinivasan N Perumal MV Jayamoorthy K 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(1):137-147
A series of substituted imidazoles have been synthesized in very good yield under solvent free condition by grinding 1,2-diketone, arylaldehyde, arylamine and ammonium acetate in the presence of molecular iodine as the catalyst. The short reaction time, good yield and easy workup make this protocol practically and economically attractive and the imidazoles are characterized by NMR spectra, X-ray, mass and CHN analysis. The push-pull character of series of imidazoles have been analyzed by the quotient of the occupations of the bonding (π) and anti-bonding (π*) orbitals of the central linking -N=C-C=C- unit. Excellent correlation of the push-pull parameter with the corresponding bond lengths d(CN) and d(CC) strongly recommend both the occupation quotients (π*/π) and the corresponding bond lengths are reasonable sensors for quantifying the push-pull character and for the molecular hyperpolarizability ?(0) of these compounds. To support the experimental results, theoretical calculations (heat of formation, NLO, NBO and vibrational analysis) were also made. Within this context, reasonable conclusions concerning the steric hindrance in the chromospheres, push-pull character, hyperpolarizability of the imidazoles and their application as NLO materials will be drawn. 相似文献
10.
Ln[N(SiMe3)2]3‐Catalyzed Cross‐Diinsertion of CN/CC into an NH Bond: Facile Synthesis of 1,2,4‐Trisubstituted Imidazoles from Propargylamines and Nitriles
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Longcheng Hong Yinlin Shao Lixin Zhang Prof. Dr. Xigeng Zhou 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8551-8555
A lanthanide‐catalyzed sequential insertion of C?N and C?C into an N?H bond is presented. The convenient reaction, which proceeds under mild conditions, is an efficient method for preparing 1,2,4‐trisubstituted imidazoles directly from readily available propargylamines and nitriles. 相似文献
11.
Full Functionalization of the Imidazole Scaffold by Selective Metalation and Sulfoxide/Magnesium Exchange
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Christoph Sämann Estibaliz Coya Prof. Dr. Paul Knochel 《Angewandte Chemie (International ed. in English)》2014,53(5):1430-1434
A simple, flexible, and straightforward method for the functionalization of all the positions of the imidazole heterocycle through regioselective arylations, allylations, acylations, and additions to aldehydes is disclosed. Starting from the readily available key imidazole 1 , highly functionalized imidazole derivatives have been synthesized in a regioselective manner from directed metalations and a sulfoxide/magnesium exchange. Moreover, the selective N3‐alkylation followed by deprotection of N1 (trans‐N‐alkylation) allows the regioselective N‐alkylation of complex imidazoles. 相似文献
12.
Mannepalli Lakshmi Kantam Gopaladasu Tirupati Venkanna Kota Balaji Shiva Kumar Vura Bala Subrahmanyam 《Helvetica chimica acta》2010,93(5):974-979
N‐Arylation of N‐containing heterocycles, such as pyrazoles, imidazoles, and benzimidazoles with aryl‐, heteroaryl‐, and vinylboronic acids was efficiently carried out by copper fluorapatite (CuFAP) catalyst in MeOH at room temperature under base‐free conditions. The N‐arylated heterocycles were isolated in good‐to‐excellent yields. 相似文献
13.
An efficient synthesis of imidazoles with isotope labeling at different positions of the five-membered ring was developed. We carried out a detailed mechanistic study of the photosensitized oxidation of isotope-labeled imidazole derivatives. A new product, CO(2), was observed in the photooxidation of 2-H,N1-H imidazoles, but not in 2-substitituted imidazoles. The carbon of CO(2) derives from the 2C of imidazole. As shown by 18O experiments, both oxygen atoms of CO(2) originate mainly from one molecule of oxygen. Transient intermediates were detected by low-temperature NMR in the photosensitized oxidation of the isotope-labeled imidazoles. Quantitative analysis of the 13C NMR at different temperatures and times correlates the formation of one intermediate with the loss of another, thus allowing the complete decomposition pathway of the transient intermediates to be established. Singlet oxygen reacts with 4,5-diphenylimidazole via a [4 + 2] cycloaddition to form a 2,5-endoperoxide, which, upon warming, decomposes to a hydroperoxide. The hydroperoxide in one pathway loses water to form an imidazolone 7, which is hydrolyzed to a hydroxyimidazol-2-one 11. In another pathway, the hydroperoxide rearranges to diol 8. The diol rearranges to a carbamate 9 by opening and reclosing the five-membered ring. 9 decomposes to CO(2) and benzil diimine. A labile NH in the imidazole is crucial for the decomposition of the initially formed endoperoxide, otherwise the endoperoxide decomposes to regenerate starting material. Many similarities exist between the photooxidations of imidazole and guanosine in organic solvent, suggesting that the two reactions share a similar reaction mechanism with singlet oxygen. 相似文献
14.
The insoluble resins synthesized by attaching imidazoles to poly(chloromethylstyrene-co-divinylbenzene) effectively hydrolyzed albumin with half-life as short as 20 min at pH 7 and 25 degrees C. Thus, peptide hydrolysis was accomplished with imidazole in an artificial system for the first time. The imidazole-based artificial proteinases manifested optimum activity at pH 7-8. The proteolytic activity of the imidazole-based artificial proteinases exceeded that of previously reported organic artificial proteinases including catalytic antibodies. High proteolytic activity was observed when imidazole was attached to the resin through the C-2 atom instead of the N atom. The catalytic activity was greatly reduced when the content of imidazole was lowered. This indicates catalytic cooperation of at least two proximal imidazole moieties attached to the resin. Possible mechanisms for the effective protein hydrolysis by the proximal imidazoles are presented. 相似文献
15.
Fifteen substituted di-heterocyclic imidazoles were prepared. Ten substituted pyrazolylimidazoles were obtained by cyclocondensation of α-oxo-α-imidazolylketene dithioacetal or N, S-acetals with hydrazine and by ring-chain transformation of cyclic α-oxo-α-imidazolylketene N, O-acetals. Five isoxazolylimidazoles were obtained by reaction of α-oxo-α-imidazolylketene dithioacetal with hydroxylamine. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9:317–320, 1998 相似文献
16.
Andersson M Hedin J Johansson P Nordström J Nydén M 《The journal of physical chemistry. A》2010,114(50):13146-13153
Synthetic imidazole ligands are typically substituted at the N(1) ((1)-Im) position while natural imidazole ligands are substituted at the C(4) ((4)-Im) position. To outline the difference in coordination properties, the methyl-substituted imidazoles Me(4)-Im and Me(1)-Im were complexed with CuCl(2) and ZnCl(2) and investigated by NMR relaxometry, electron paramagnetic resonance, far-Fourier transform IR vibrational spectroscopy, and ab initio calculations. Me(4)-Im, Me(1)-Im, and Im in excess form the usual tetragonal D(4h) [CuL(4)X(2)] complexes with CuCl(2) whereas the methylated imidazoles form pseudotetrahedral C(2v) complexes instead of the usual octahedral O(h) [ZnIm(6)](2+) complex. All imidazoles display a high degree of covalence in the M-L σ- and π-bonds and the π-interaction strength affects the relative energies of complexation. Opportunities to tailor complexes by the chemical properties of the substituents are envisaged due to the role of the inductive and hyperconjugative effects, rather than position. 相似文献
17.
Susruta Majumdar 《合成通讯》2013,43(23):3537-3548
We report a novel synthesis of N‐alkyl‐N‐alkyloxycarbonylaminomethyl (NANAOCAM) prodrugs of acetaminophen, theophylline, and 6‐mercaptopurine by alkylation of the corresponding drug molecule with N‐alkyl‐N‐alkyloxycarbonylaminomethyl chlorides in good yield. Most of the alkylating agents were efficiently synthesized by chloromethylation of N‐alkyl carbamic acid alkyl esters, which in turn were made from alkyl amines and alkyl chloroformates. In cases where the alkyl chloroformates were not available, synthesis of N‐alkyl carbamic acid alkyl esters was accomplished by converting an alcohol to a chloroformate or to an activated acylating agent such as acyl imidazoles or p‐nitrophenylcarbonate esters, followed by their reaction with alkyl amines. 相似文献
18.
Sisko J Kassick AJ Mellinger M Filan JJ Allen A Olsen MA 《The Journal of organic chemistry》2000,65(5):1516-1524
This article describes efficient and mild protocols for preparing polysubstituted imidazoles in a single pot from aryl-substituted tosylmethyl isocyanide (TosMIC) reagents and imines generated in situ. Traditional imine-forming reactions employing virtually any aldehyde and amine followed by addition of the TosMIC reagent delivers 1,4,5-trisubstituted imidazoles with predictable regiochemistry. Employing chiral amines and aldehydes, particularly those derived from alpha-amino acids, affords imidazoles with asymmetric centers appended to N-1 or C-5 with excellent retention of chiral purity. 1,4-Disubstituted imidazoles are also readily prepared by a simple variant of the above procedure. Selecting glyoxylic acid as the aldehyde component of this procedure leads to intermediates such as 48, which readily undergo decarboxylation and elimination of the tosyl moiety to deliver 1,4-disubstituted imidazoles in high yields. Alternatively, using NH(4)OH as the amine component in conjunction with a variety of aldehydes delivers 4, 5-disubstituted imidazoles in moderate to good yields in a single pot while avoiding the need for protecting groups. Finally, the facile preparation of mono- and disubstituted oxazoles from these TosMIC reagents and aldehydes is described. 相似文献
19.
Microwave‐assisted arylation of 1H‐imidazoles and N,N′‐carbonyldiimidazole under ligand‐free copper‐mediated conditions in tetraethyl orthosilicate is reported. Valuable evidence for understanding of the Cu‐catalyzed mechanism of the Ullmann reaction is also presented. 相似文献
20.
Long Yang Ralf Steinbock Alexej Scheremetjew Rositha Kuniyil Lars H. Finger Antonis M. Messinis Lutz Ackermann 《Angewandte Chemie (International ed. in English)》2020,59(27):11130-11135
A ruthenium‐catalyzed electrochemical dehydrogenative annulation reaction of imidazoles with alkynes has been established, enabling the preparation of various bridgehead N‐fused [5,6]‐bicyclic heteroarenes through regioselective electrochemical C?H/N?H annulation without chemical metal oxidants. Novel azaruthenabicyclo[3.2.0]heptadienes were fully characterized and identified as key intermediates. Mechanistic studies are suggestive of an oxidatively induced reductive elimination pathway within a ruthenium(II/III) regime. 相似文献