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1.
Rhodium(III)‐Catalyzed [3+2] Annulation of 5‐Aryl‐2,3‐dihydro‐1H‐pyrroles with Internal Alkynes through C(sp2)H/Alkene Functionalization
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Ming‐Bo Zhou Rui Pi Ming Hu Yuan Yang Ren‐Jie Song Dr. Yuanzhi Xia Prof. Dr. Jin‐Heng Li 《Angewandte Chemie (International ed. in English)》2014,53(42):11338-11341
This study describes a new rhodium(III)‐catalyzed [3+2] annulation of 5‐aryl‐2,3‐dihydro‐1H‐pyrroles with internal alkynes using a Cu(OAc)2 oxidant for building a spirocyclic ring system, which includes the functionalization of an aryl C(sp2)? H bond and addition/protonolysis of an alkene C?C bond. This method is applicable to a wide range of 5‐aryl‐2,3‐dihydro‐1H‐pyrroles and internal alkynes, and results in the assembly of the spiro[indene‐1,2′‐pyrrolidine] architectures in good yields with excellent regioselectivities. 相似文献
2.
Alexander Briceo Reinaldo Atencio Raquel Gil Alejandra Nobrega 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(8):o441-o444
The structure of trans‐3‐(3‐pyridyl)acrylic acid, C8H7NO2, (I), possesses a two‐dimensional hydrogen‐bonded array of supramolecular ribbons assembled via heterodimeric synthons between the pyridine and carboxyl groups. This compound is photoreactive in the solid state as a result of close contacts between the double bonds of neighbouring molecules [3.821 (1) Å] along the a axis. The crystal structure of the photoproduct, rctt‐3,3′‐(3,4‐dicarboxycyclobutane‐1,2‐diyl)dipyridinium dichloride, C16H16N2O42+·2Cl−, (II), consists of a three‐dimensional hydrogen‐bonded network built from crosslinking of helical chains integrated by self‐assembly of dipyridinium cations and Cl− anions via different O—H...Cl, C—H...Cl and N+—H...Cl hydrogen‐bond interactions. 相似文献
3.
Jian‐Qiang Huang Chun‐Yu Ho 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(17):5758-5762
A cross‐hydroalkenylation/rearrangement cascade (HARC), using a cyclopropene and alkyne as substrate pairs, was achieved for the first time by using new [(NHC)Ni(allyl)]BArF catalysts (NHC=N‐heterocyclic carbenes). By controlling the (NHC)NiIIH relative insertion reactivity with cyclopropene and alkyne, a broad scope of cyclopentadienes was obtained with highly selectively. The structural features of the new (NHC)NiII catalyst were important for the success of the reaction. The mild reaction conditions employed may serve as an entry for exploring (NHC)NiII‐assisted vinylcyclopropane rearrangement reactivity. 相似文献
4.
The photochemical behavior of various substituted epoxycarbonyl compounds consisting of more than one possible photo‐labile site (i.e. δ‐hydrogen, β‐hydrogen and epoxide ring) has been investigated. These compounds on photo‐irradiation produced the β‐hydroxyenones in an eco‐friendly green approach. Mechanistically, these photo‐transformations have been envisaged to occur via an intramolecular β‐hydrogen abstraction by the carbonyl group of benzoyl moiety to generate the 1,3‐biradical followed by epoxide ring opening that isomerizes into the photoproducts. The photolysis of the probed epoxy ketones didn’t furnish any photoproduct through δ‐hydrogen abstraction, whatsoever. This exclusive preference for β‐H abstraction over δ‐H abstraction by carbonyl group has been vindicated by the MM2 energy mini‐ mized program for the investigated photochemical substrates. The structures of these photoproducts were established from the analysis of their spectral parameters (IR, 1H/13C NMR and Mass) and single crystal X‐ray crystallography data. 相似文献
5.
An efficient approach for the preparation of functionalized 2‐aryl‐2,5‐dihydro‐5‐oxo‐4‐[2‐(phenylmethylidene)hydrazino]‐1H‐pyrroles is described. The four‐component reaction between aldehydes, NH2NH2?H2O, dialkyl acetylenedicarboxylates, and 1‐aryl‐N,N′‐bis(arylmethylidene)methanediamines proceeds in EtOH under reflux in good‐to‐excellent yields (Scheme 1). The structures of 4 were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS, and, in the case of 4f , by X‐ray crystallography). A plausible mechanism for this type of reaction is proposed (Scheme 2). 相似文献
6.
A series of m‐ and p‐substituted 1‐phenyl, 1‐benzyl, 1‐benzoyl, and 1‐(2‐phenylethyl)pyrroles was prepared and their 1H and 13C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of the β? H and the β? C of pyrroles [except 1‐(2‐phenylethyl)pyrroles] and the Hammettt σ. The observation may be explained in terms of the electronic effects of the substituents which are transmitted through bonds and through space by interaction of the p orbitals between β? Cs of the pyrrole ring and m‐ and p? Cs of the phenyl ring. Substituent constants of 1‐pyrrolyl, 1‐pyrrolylmethyl, and 1‐pyrroloyl groups for the 1H and 13C chemical shifts of phenyl ring are also presented. 相似文献
7.
《Magnetic resonance in chemistry : MRC》2002,40(2):114-122
1H and 13C NMR spectroscopy of a series of 1‐vinyl‐2‐(2′‐heteroaryl)‐pyrroles were employed for the analysis of their electronic and spatial structure. The C—H···N intramolecular interaction between the α‐hydrogen of the vinyl group and the pyridine nitrogen, a kind of hydrogen bonding, was detected in 1‐vinyl‐2‐(2′‐pyridyl)pyrrole, which disappeared in its iodide methyl derivative. It was shown that this interaction is stronger than the C—H···O and C—H···S interactions in 1‐vinyl‐2‐(2′‐furyl)‐ and ‐2‐(2′‐thienyl)‐pyrroles. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
8.
Sabbavarapu Narayana Murthy Bandaru Madhav Akkiligunta Vijay Kumar Kakulapati Rama Rao Yadavalli Venkata Durga Nageswar 《Helvetica chimica acta》2009,92(10):2118-2124
Synthesis of substituted pyrroles in H2O by using β‐cyclodextrin as a supramolecular catalyst is described. This reaction has several advantages over existing methods and provides substituted pyrroles in good‐to‐excellent yields (79–89%). The supramolecular catalysis of the reaction was studied using 1H‐NMR spectroscopy. β‐Cyclodextrin can be recovered and reused several times without loss of activity. 相似文献
9.
Insertion of Nitriles into Zirconocene 1‐aza‐1,3‐diene Complexes: Chemoselective Synthesis of N–H and N‐Substituted Pyrroles
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Shasha Yu Meijun Xiong Xin Xie Prof. Yuanhong Liu 《Angewandte Chemie (International ed. in English)》2014,53(43):11596-11599
The direct insertion of nitriles into zirconocene‐1‐aza‐1,3‐diene complexes provides an efficient, chemoselective, and controllable synthesis of N‐H and N‐substituted pyrroles upon acidic aqueous work‐up. The outcome of the reaction (that is, the formation of N‐H or N‐substituted pyrroles) results from the different cyclization patterns, which depend on the relative stability and reactivity of the enamine–imine tautomers formed by hydrolysis of the diazazirconacycles. 相似文献
10.
Ali Souldozi Ali Ramazani Ali Reza Dadrass Katarzyna Ślepokura Tadeusz Lis 《Helvetica chimica acta》2012,95(2):339-348
The reaction between secondary amines, benzoyl isothiocyanate, and dialkyl acetylenedicarboxylates (=dialkyl but‐2‐ynedioates) in the presence of silica gel (SiO2) led to alkyl 2‐(dialkylamino)‐4‐phenylthiazole‐5‐carboxylates in fairly high yields. The structures of the products were confirmed by their IR, 1H‐ and 13C‐NMR, and mass spectra, and by a single‐crystal X‐ray structure determination. 相似文献
11.
Ethan A. Wappes Stacy C. Fosu Trevor C. Chopko Prof. Dr. David A. Nagib 《Angewandte Chemie (International ed. in English)》2016,55(34):9974-9978
The Cδ?H amination of unactivated, secondary C?H bonds to form a broad range of functionalized pyrrolidines has been developed by a triiodide (I3?)‐mediated strategy. By in situ 1) oxidation of sodium iodide and 2) sequestration of the transiently generated iodine (I2) as I3?, this approach precludes undesired I2‐mediated decomposition which can otherwise limit synthetic utility to only weak C(sp3)?H bonds. The mechanism of this triiodide‐mediated cyclization of unbiased, secondary C(sp3)?H bonds, by either thermal or photolytic initiation, is supported by NMR and UV/Vis data, as well as intercepted intermediates. 相似文献
12.
Olga I. Tarzi Hiroshi Nonami Rosa Erra‐Balsells 《Journal of mass spectrometry : JMS》2009,44(2):260-277
The thermal stability of several commonly used crystalline matrix‐assisted ultraviolet laser desorption/ionization mass spectrometry (UV‐MALDI‐MS) matrices, 2,5‐dihydroxybenzoic acid (gentisic acid; GA), 2,4,6‐trihydroxyacetophenone (THA), α‐cyano‐4‐hydroxycinnamic acid (CHC), 3,5‐dimethoxy‐4‐hydroxycinnamic acid (sinapinic acid; SA), 9H‐pirido[3,4‐b]indole (nor‐harmane; nor‐Ho), 1‐methyl‐9H‐pirido[3,4‐b]indole (harmane; Ho), perchlorate of nor‐harmanonium ([nor‐Ho + H]+) and perchlorate of harmanonium ([Ho + H]+) was studied by heating them at their melting point and characterizing the remaining material by using different MS techniques [electron ionization mass spectrometry (EI‐MS), ultraviolet laserdesorption/ionization‐time‐of‐flight‐mass spectrometry (UV‐LDI‐TOF‐MS) and electrospray ionization‐time‐of‐flight‐mass spectrometry (ESI‐TOF‐MS)] as well as by thin layer chromatography analysis (TLC), electronic spectroscopy (UV‐absorption, fluorescence emission and excitation spectroscopy) and 1H nuclear magnetic resonance spectroscopy (1H‐NMR). In general, all compounds, except for CHC and SA, remained unchanged after fusion. CHC showed loss of CO2, yielding the trans‐/cis‐4‐hydroxyphenylacrilonitrile mixture. This mixture was unambiguously characterized by MS and 1H‐NMR spectroscopy, and its sublimation capability was demonstrated. These results explain the well‐known cluster formation, fading (vanishing) and further recovering of CHC when used as a matrix in UV‐MALDI‐MS. Commercial SA (SA 98%; trans‐SA/cis‐SA 5 : 1) showed mainly cis‐ to‐trans thermal isomerization and, with very poor yield, loss of CO2, yielding (3′,5′‐dimethoxy‐4′‐hydroxyphenyl)‐1‐ethene as the decarboxilated product. These thermal conversions would not drastically affect its behavior as a UV‐MALDI matrix as happens in the case of CHC. Complementary studies of the photochemical stability of these matrices in solid state were also conducted. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
13.
Boris A. Trofimov Lyubov' N. Sobenina Al'bina I. Mikhaleva Ol'Ga V. Petrova Vladislav N. Drichkov Igor A. Ushakov Ol'Ga A. Tarasova Darya‐Suren D. Toryashinova Yuriy Yu. Rusakov Leonid B. Krivdin 《Journal of heterocyclic chemistry》2007,44(3):505-513
14.
Wayland E. Noland Nicholas P. Lanzatella Rozalin R. Dickson Mary E. Messner Huy H. Nguyen 《Journal of heterocyclic chemistry》2013,50(4):795-808
Diels–Alder reactions of 5‐methylthio‐2‐vinyl‐1H‐pyrroles with maleimides followed by isomerization gave tetrahydroindoles in moderate to good yield. Aromatization using activated MnO2 in refluxing toluene gave the corresponding 2‐methylthioindoles in good yields, and demethylthioation using Raney nickel gave the 2‐H indoles in excellent yields. The protection of the adducts produced aromatization in improved yield, demonstrating the effectiveness of the methylthio group as a protecting group for pyrroles; however, 5‐methylthio‐2‐vinylpyrrole was shown to perform with slightly less efficiency than 2‐vinylpyrrole in Diels–Alder reactions, indicating the protective group was more deactivating than desired. This route toward indoles offers high convergency and conveniently available starting materials that are easily purified. Bis‐methylthioated vinylpyrroles were shown to have potential as highly activated Diels–Alder dienes. 相似文献
15.
Mariya Edeleva Sylvain R. A. Marque Kuanish Kabytaev Yohann Guillaneuf Didier Gigmes Elena Bagryanskaya 《Journal of polymer science. Part A, Polymer chemistry》2013,51(6):1323-1336
Thermal decomposition of four tertiary N‐(2‐methylpropyl)‐N‐(1‐diethylphosphono‐2,2‐dimethylpropyl)‐N‐oxyl (SG1)‐based alkoxyamines (SG1‐C(Me)2‐C(O)‐OR, R = Me, tBu, Et, H) has been studied at different experimental conditions using 1H and 31P NMR spectroscopies. This experiment represents the initiating step of methyl methacrylate polymerization. It has been shown that H‐transfer reaction occurs during the decomposition of three alkoxyamines in highly degassed solution, whereas no products of H‐transfer are detected during decomposition of SG1‐MAMA alkoxyamine. The value of the rate constant of H‐transfer for alkoxyamines 1 (SG1‐C(Me)2‐C(O)‐OMe) and 2 ( SG1‐C(Me)2‐C(O)‐OtBu) has been estimated as 1.7 × 103 M?1s?1. The high influence of oxygen on decomposition mechanism is found. In particular, in poorly degassed solutions, nearly quantitative formation of oxidation product has been observed, whereas at residual pressure of 10?5 mbar, the main products originate from H‐atom transfer reaction. The acidity of the reaction medium affects the decomposition mechanism suppressing the H‐atom transfer. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
16.
Three 1,3‐bridged polycyclic cyclopropenes, exo‐8‐oxatricyclo[3.2.1.02,4]octa‐2,6‐diene ( 10 ), endo‐8‐oxatricyclo[3.2.1.02,4]octa‐2,6‐diene ( 11 ), and exo‐6,7‐benzo‐1,5‐diphenyl‐8‐oxatricyclo[3.2.1.02,4]octa‐2,6‐diene ( 12 ), have been synthesized by elimination of 2‐chloro‐3‐trimethylsilyl‐8‐oxatricyclo[3.2.1.02,4]‐oct‐6‐enes, 17 , 18 and 30 , which were generated from 1‐chloro‐3‐trimethylsilylcyclopropene with furan and diphenylisobenzofuran. We have demonstrated a facile route to synthesize the highly strained 1,3‐fused polycyclic cyclopropenes, 10 , 11 , and 12 . The stereochemistry of the Diels‐Alder reactions of cyclopropene 16 with furan and DPIBF are different. Cyclopropene 16 was treated with furan to form exo‐exo and endo‐exo adducts (5:2) and treated with DPIBF to generate an exo‐exo adduct. Compounds 10 , 11 and 12 undergo isomerization reactions to form benzaldehyde and phenyl 4‐phenyl‐[1]naphthyl ketone to release strain energies via diradical mechanisms. 相似文献
17.
Iris de Krom Leen E. E. Broeckx Dr. Martin Lutz Prof. Dr. Christian Müller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3676-3684
The bidentate P,N hybrid ligand 1 allows access for the first time to novel cationic phosphinine‐based RhIII and IrIII complexes, broadening significantly the scope of low‐coordinate aromatic phosphorus heterocycles for potential applications. The coordination chemistry of 1 towards RhIII and IrIII was investigated and compared with the analogous 2,2′‐bipyridine derivative, 2‐(2′‐pyridyl)‐4,6‐diphenylpyridine ( 2 ), which showed significant differences. The molecular structures of [RhCl(Cp*)( 1 )]Cl and [IrCl(Cp*)( 1 )]Cl (Cp*=pentamethylcyclopentadienyl) were determined by means of X‐ray diffraction and confirm the mononuclear nature of the λ3‐phosphinine–RhIII and IrIII complexes. In contrast, a different reactivity and coordination behavior was found for the nitrogen analogue 2 , especially towards RhIII as a bimetallic ion pair [RhCl(Cp*)( 2 )]+[RhCl3(Cp*)]? is formed rather than a mononuclear coordination compound. [RhCl(Cp*)( 1 )]Cl and [IrCl(Cp*)( 1 )]Cl react with water regio‐ and diastereoselectively at the external P?C double bond, leading exclusively to the anti‐addition products [MCl(Cp*)( 1 H ? OH)]Cl as confirmed by X‐ray crystal‐structure determination. 相似文献
18.
Chaza Darwich Konstantin Karaghiosoff Thomas M. Klapötke Prof. Dr. Carles Miró Sabaté 《无机化学与普通化学杂志》2008,634(1):61-68
3,4,5‐Triamino‐1,2,4‐triazolium iodide ( 1 ) was obtained in good yield and purity and characterized using vibrational (IR, Raman) and multinuclear NMR spectroscopy (1H, 13C, 15N), EA, MS, DSC, and X‐ray crystallography. The compound was synthesized by two different methods rendering two different polymorphs (α and β) as proved by X‐ray measurements, vibrational spectroscopy and DSC. 1‐Methyl‐3,4,5‐triamino‐1,2,4‐triazolium iodide ( 2 ) was synthesized by reaction of guanazine with methyliodide and fully characterized by the same techniques mentioned above. Both compounds showed to be suitable starting materials for the synthesis of guanazinium salts of energetic interest. 相似文献
19.
AntnioF.DeC. Alcntara MariaG.F. Vaz HumbertoO. Stumpf Dorila Pil‐Veloso WagnerB. DeAlmeida 《Helvetica chimica acta》2004,87(2):425-438
Conformational studies of 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐1‐yl)imidazolidine ( 1a ) and 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐3‐yl)imidazolidine ( 1b ), carried out by using 1D 1H‐ and 13C‐NMR and 2D HMQC, HMBC, and NOESY experiments and with the aid of theoretical calculations, indicate that the OH groups are trans to the pyridinyl substituent. Because the two 1H‐NMR signals of the Me groups are distinguishable and do not change between 290 and 380 K, it is proposed that 1a and 1b have each only one conformation in this temperature range. This behavior was not found with 1,3‐dihydroxy‐4,4,5,5‐tetramethyl‐2‐(pyridin‐2‐yl)imidazolidine ( 1c ) because its Me 1H‐NMR signals cross over at 300 K. Hence, more than one conformation must be present, beyond those produced by simple inversions. Theoretical calculations including temperature and solvent effects were performed to provide further information on the conformational analysis and to help to assign the NMR data. The combination of NMR measurements and quantum‐chemical calculations is shown to be a very promising strategy for conformational analysis studies in solution. 相似文献
20.
Youla Su Shang Gao Yue Huang Dr. Aijun Lin Prof. Dr. Hequan Yao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(44):15820-15825
A solvent‐controlled C2/C5‐selective alkenylation of 3,4‐disubstituted pyrroles has been developed. The C3 substituent of pyrroles proved crucial to the regioselectivity. Substrates bearing directing groups at the C3 position exhibited excellent C2‐selectivities in chelation‐assisted C?H activation in toluene or 1,4‐dioxane. However, a DMSO/DMF solvent system could override the chelation effect of weak directing groups, such as carboxylate and carbonyl groups, favoring instead regioselectivity towards the more electron‐rich C5 position. A series of 3‐carboxylate and 3‐carbonyl pyrroles were tested and showed moderate to good yields with good regioselectivities for both C2‐ and C5‐alkenylation process. 相似文献