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1.
The 5,5‐dimethylpyrazolidin‐3‐one ( 4 ), prepared from ethyl 3‐methylbut‐2‐enoate ( 3 ) and hydrazine hydrate, was treated with various substituted benzaldehydes 5a – i to give the corresponding (1Z)‐1‐(arylmethylidene)‐5,5‐dimethyl‐3‐oxopyrazolidin‐1‐ium‐2‐ide azomethine imines 6a – i . The 1,3‐dipolar cycloaddition reactions of azomethine imines 6a – h with dimethyl acetylenedicarboxylate (=dimethyl but‐2‐ynedioate; 7 ) afforded the corresponding dimethyl pyrazolo[1,2‐a]pyrazoledicarboxylates 8a – h , while by cycloaddition of 6 with methyl propiolate (=methyl prop‐2‐ynoate; 9 ), regioisomeric methyl pyrazolo[1,2‐a]pyrazolemonocarboxylates 10 and 11 were obtained. The regioselectivity of cycloadditions of azomethine imines 6a – i with methyl propiolate ( 9 ) was influenced by the substituents on the aryl residue. Thus, azomethine imines 6a – e derived from benzaldehydes 5a – e with a single substituent or without a substituent at the ortho‐positions in the aryl residue, led to mixtures of regioisomers 10a – e and 11a – e . Azomethine imines 6f – i derived from 2,6‐disubstituted benzaldehydes 5f – i gave single regioisomers 10f – i .  相似文献   

2.
The N‐substituted isomeric (4Z,5Z)‐ and (4E,5Z)‐4,5‐diethylideneoxazolidin‐2‐ones 5 and 6 were synthesized, the latter being favored during the one‐step process from the α‐diketone 1c and different isocyanates. The steric interaction between the N‐substituent and the Me group attached to the exocyclic diene moiety plays a decisive role in controlling the observed stereoselectivity, as suggested by the calculated free energies of the two isomers. Both dienes undergo efficient additions to symmetric dienophiles in thermal Diels‐Alder reactions to yield the adducts 11 and 13 , respectively. These molecules displayed interesting C−H⋅⋅⋅π, and C−H⋅⋅⋅X (X=O, Cl) interactions according to their X‐ray crystal structures. Isomers 6 suffered highly stereo‐ and regioselective additions with nonsymmetrical dienophiles such as methyl vinyl ketone or methyl propiolate. Steric interactions, promoted by the inward‐pointing Me group in 6 , seem to explain such selectivity. These results have also been rationalized by ab initio calculations in terms of the FMO theory.  相似文献   

3.
Well‐dispersed ammonium aluminum carbonate hydroxide (NH4‐Dw) and γ‐AlOOH nanostructures with controlled morphologies have been synthesized by employing an ionic‐liquid‐assisted hydrothermal process. The basic strategies that were used in this work were: 1) A controllable phase transition from NH4‐Dw to γ‐AlOOH could be realized by increasing the reaction temperature and 2) the morphological evolution of NH4‐Dw and γ‐AlOOH nanostructures could be influenced by the concentration of the ionic liquid. Based on these experimental results, the main objective of this work was to clarify the effect models of the ionic liquids on the synthesis of NH4‐Dw and γ‐AlOOH nanostructures, which could be divided into cationic‐ or anionic‐dominant effect models, as determined by the different surface structures of the targets. Specifically, under the cationic‐dominant regime, the ionic liquids mainly showed dispersion effects for the NH4‐Dw nanostructures, whereas the anionic‐dominant model could induce the self‐assembly of the γ‐AlOOH particles to form hierarchical structures. Under the guidance of the proposed models, the effect of the ionic liquids would be optimized by an appropriate choice of cations or anions, as well as by considering the different effect models with the substrate surface. We expect that such effect models between ionic liquids and the target products will be helpful for understanding and designing rational ionic liquids that contain specific functional groups, thus open up new opportunities for the synthesis of inorganic nanomaterials with new morphologies and improved properties. In addition, these as‐prepared NH4‐Dw and γ‐AlOOH nanostructures were converted into porous γ‐Al2O3 nanostructures by thermal decomposition, whilst preserving the same morphology. By using HRTEM and nitrogen‐adsorption analysis, the obtained γ‐Al2O3 samples were found to have excellent porous properties and, hence, may have applications in catalysis and adsorption.  相似文献   

4.
Two methyl derivatives, five‐membered methyl 2‐{2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4‐oxo‐4,5‐dihydro‐1,3‐thiazol‐5‐ylidene}acetate, C20H16N4O3S, (I), and six‐membered 2‐[2‐(9,10‐dihydroacridin‐9‐ylidene)‐1‐methylhydrazinyl]‐4H‐1,3‐thiazin‐4‐one, C18H14N4OS, (II), were prepared by the reaction of the N‐methyl derivative of 4‐(9,10‐dihydroacridin‐9‐ylidene)thiosemicarbazide, C14H12N4S, (III), with dimethyl acetylenedicarboxylate and methyl propiolate, respectively. The crystal structures of (I), (II) and (III) are molecular and can be considered in two parts: (i) the nearly planar acridine moiety and (ii) the singular heterocyclic ring portion [thiazolidine for (I) and thiazine for (II)] including the linking amine and imine N atoms and the methyl C atom, or the full side chain in the case of (III). The structures of (I) and (II) are stabilized by N—H...O hydrogen bonds and different π–π interactions between acridine moieties and thiazolidine and thiazine rings, respectively.  相似文献   

5.
In this work, the geometrical and electronic properties of the mono cationic ionic liquid 1‐hexyl‐3‐methylimidazolium halides ([C6(mim)]+_X?, X=Cl, Br and I) and dicationic ionic liquid 1,3‐bis[3‐methylimidazolium‐1‐yl]hexane halides ([C6(mim)2X2], X=Cl, Br and I) were studied using the density functional theory (DFT). The most stable conformer of these two types ionic liquids (IL) are determined and compared with each other. Results show that in the most stable conformers, in both monocationic ILs and dicationic ILs, the Cl? and Br? anions prefer to locate almost in the plane of the imidazolium ring whereas the I? anion prefers nearly vertical location respect to the imidazolium ring plan. Comparison of hydrogen bonding and ionic interactions in these two types of ionic liquids reveals that these ionic liquids can be formed hydrogen bond by Cl? and Br? anion. The calculated thermodynamic functions show that the interaction of cation — anion pair in the dicationic ionic liquids are more than monocationic ionic liquids and these interactions decrease with increasing the halide anion atomic weight.  相似文献   

6.
A cationic palladium complex, [Pd(PPh3)2(MeCN)2](BF4)2, catalyzed the carbonylation of 2,3‐dien‐1‐ols under mild conditions. The dienols bearing two or more alkyl substituents on the diene part afforded 1,3‐diene‐2‐carboxylic acids successfully in tetrahydrofuran (THF), while those possessing one or no alkyl substituent gave polymers of the products exclusively. The former afforded the corresponding methyl esters in good yields when the reactions were carried out in methanol, while the latter afforded mainly the Diels–Alder reaction products of the resulting esters. An alkylidene group‐substituted π‐allylpalladium species has been presumed to be an intermediate. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

7.
The atom transfer radical copolymerization of N‐substituted maleimides such as N‐phenylmaleimide (PhMI), N‐cyclohexylmaleimide (ChMI), and N‐butylmaleimide (NBMI) with styrene initiated with dendritic polyarylether 2‐bromoisobutyrates in an ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim][PF6]), at room temperature and anisole at 110 °C was investigated. The dendritic‐linear block copolymers obtained in ionic liquid possessed well‐defined molecular weight and low polydispersity (1.05 < Mw/Mn < 1.32) and could be used as a macroinitiator for chain‐extension polymerization, suggesting the living nature of the reaction system. The ionic liquids containing catalyst could be recycled in the atom transfer radical polymerization systems without further treatment. Compared with polymerization conducted in anisole, the polymerization in ionic liquid had a stronger tendency for alternation. The tendency for alternation decreased in the order PhMI > NBMI > ChMI in [bmim][PF6] and PhMI > ChMI > NBMI in anisole. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2156–2165, 2003  相似文献   

8.
Two diphosphane ligands – 2,5‐bis(2‐(diphenylphosphino)‐5‐R)phenyl)‐1,3,4‐oxadiazole ( L1 , R = H, L2 , R = OMe) and their binuclear complexes, L1Cu and L2Cu , were prepared and characterized. The molecular structures of L1Cu and L2Cu , as perchlorate salts, were established by X‐ray crystallography, which showed them to be binuclear complexes with each Cu atom tetrahedrally coordinated by two P atoms and two N atoms. The ligands and their Cu(I) complexes catalyzed Sonogashira coupling reactions of iodobenzene with phenylacetylene in the presence of K2CO3 under Pd‐free conditions. Coupling reactions catalyzed by L1 or L2 with Cu(MeCN)4ClO4 in situ exhibited better yields than those by the corresponding Cu(I) complexes L1Cu or L2Cu . Detailed studies showed L1 or L2 with Cu(MeCN)4ClO4 to be suitable catalysts for the coupling reaction of terminal alkynes and aryl halides. The coupling reactions of aryl iodides with electron‐withdrawing groups showed better results. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

9.
The comparative studies on the miscibility and phase behavior between the blends of linear and star‐shaped poly(2‐methyl‐2‐oxazoline) with poly(vinylidene fluoride) (PVDF) were carried out in this work. The linear poly(2‐methyl‐2‐oxazoline) was synthesized by the ring opening polymerization of 2‐methyl‐2‐oxazoline in the presence of methyl p‐toluenesulfonate (MeOTs) whereas the star‐shaped poly(2‐methyl‐2‐oxazoline) was synthesized with octa(3‐iodopropyl) polyhedral oligomeric silsesquioxane [(IC3H6)8Si8O12, OipPOSS] as an octafunctional initiator. The polymers with different topological structures were characterized by means of Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. It is found that the star‐shaped poly(2‐methyl‐2‐oxazoline) was miscible with poly(vinylidene fluoride) (PVDF), which was evidenced by single glass‐transition temperature behavior and the equilibrium melting‐point depression. Nonetheless, the blends of linear poly(2‐methyl‐2‐oxazoline) with PVDF were phase‐separated. The difference in miscibility was ascribed to the topological effect of PMOx macromolecules on the miscibility. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 942–952, 2006  相似文献   

10.
Three copper(II) complexes of the polydentate N‐donor ligand [4‐(4,6‐bis(1H‐pyrazol‐1‐yl)‐1,3,5‐triazin‐2‐yl)morpholine] (L) with chlorides, nitrates, and perchlorates as anions, namely, [CuCl2(L)] · 0.5(MeCN) ( 1 ), [Cu(NO3)2(H2O)(L)] · (MeCN) ( 2 ), and [Cu(L)2](ClO4)2 · (MeCN) ( 3 ) were synthesized and structurally characterized by IR, elemental analysis and X‐ray crystallographic analysis. In these complexes, the L ligand binds the copper(II) cation in the tridentate N3 form. The coordination arrangement around the central copper(II) atom is distorted square‐pyramidal in 1 but it is distorted octahedral in 2 and 3 . The interesting noncovalent interactions such as hydrogen bonds, π–π stacking, and anion–π interactions present in the solid‐state structures are discussed. The crystal results reveal that the counteranions play important roles in determining the diverse structures of these complexes. Moreover, the PXRD, TG, DRS, and fluorescence properties of compounds 1 – 3 were investigated.  相似文献   

11.
A simple and efficient approach to synthesize a novel pyrrolocoumarin 9‐hydroxy‐8H‐pyrano[3,2‐f]indol‐2‐one ( 7 ) has been described. Starting from vanillin, the key intermediate 7‐methoxy‐1H‐indol‐6‐yl propiolate ( 6 ) was synthesized in six steps. Then, the target compound was obtained by forming pyrone‐ring and demethylation simultaneously in one step. A plausible mechanism invoking PtCl4 catalyzed one‐step reaction of cyclization and demethylation was also presented.  相似文献   

12.
Although it has not proved possible to crystallize the newly prepared cyclam–methylimidazole ligand 1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane (LIm1), the trans and cis isomers of an NiII complex, namely trans‐aqua{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate) monohydrate, [Ni(C15H30N6)(H2O)](ClO4)2·H2O, (1), and cis‐aqua{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate), [Ni(C15H30N6)(H2O)](ClO4)2, (2), have been prepared and structurally characterized. At different stages of the crystallization and thermal treatment from which (1) and (2) were obtained, a further two compounds were isolated in crystalline form and their structures also analysed, namely trans‐{1‐[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}(perchlorato)nickel(II) perchlorate, [Ni(ClO4)(C15H30N6)]ClO4, (3), and cis‐{1,8‐bis[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane}nickel(II) bis(perchlorate) 0.24‐hydrate, [Ni(C20H36N6)](ClO4)2·0.24H2O, (4); the 1,8‐bis[(1‐methyl‐1H‐imidazol‐2‐yl)methyl]‐1,4,8,11‐tetraazacyclotetradecane ligand is a minor side product, probably formed in trace amounts in the synthesis of LIm1. The configurations of the cyclam macrocycles in the complexes have been analysed and the structures are compared with analogues from the literature.  相似文献   

13.
In this study, (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylic acid hydrazide ( 5 ) was synthesized by the condensation of methyl (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylate ( 4 ) with NH2NH2⋅H2O. The (5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐carboxylic acid 2‐[(arylamino)carbonyl]hydrazides 6a – 6q were prepared by the reaction of 5 with corresponding substituted aryl isocyanates, and the N‐{5‐[(5α,7α)‐4,5‐epoxy‐3,6‐dimethoxy‐17‐methyl‐6,14‐ethenomorphinan‐7‐yl]‐1,3,4‐oxadiazol‐2‐yl}arenamines 7a – 7q were obtained via the cyclization reaction of 6a – 6q in the presence of POCl3. The synthesized compounds have a rigid morphine structure, including the 6,14‐endo‐etheno bridge and the 5‐(arylamino)‐1,3,4‐oxadiazol‐2‐yl residue at C(7) adopting the (S)‐configuration (7α). The structures of the compounds were confirmed by high‐resolution mass spectrometry (HR‐MS) and various spectroscopic methods such as FT‐IR, 1H‐NMR, 13C‐NMR, APT, and 2D‐NMR (HETCOR, COSY, INADEQUATE).  相似文献   

14.
Methyl 2‐benzamido‐4‐(3,4‐dimethoxyphenyl)‐5‐methylbenzoate, C24H23NO5, (Ia), and N‐{5‐benzoyl‐2‐[(Z)‐2‐methoxyethenyl]‐4‐methylphenyl}benzamide, C24H21NO3, (IIa), were formed via a Diels–Alder reaction of appropriately substituted 2H‐pyran‐2‐ones and methyl propiolate or (Z)‐1‐methoxybut‐1‐en‐3‐yne, respectively. Each of these cycloadditions might yield two different regioisomers, but just one was obtained in each case. In (Ia), an intramolecular N—H...O hydrogen bond closes a six‐membered ring. A chain is formed due to aromatic π–π interactions, and a three‐dimensional framework structure is formed by a combination of C—H...O and C—H...π(arene) hydrogen bonds. Compound (IIa) was formed not only regioselectively but also chemoselectively, with just the triple bond reacting and the double bond remaining unchanged. Compound (IIa) crystallizes as N—H...O hydrogen‐bonded dimers stabilized by aromatic π–π interactions. Dimers of (IIa) are connected into a chain by weak C—H...π(arene) interactions.  相似文献   

15.
Unnatural cyclic α‐amino acids play an important role in the search for biologically active compounds and macromolecules. Enantiomers of natural amino acids with a d configuration are not naturally encoded, but can be chemically synthesized. The crystal structures of two enantiomers obtained by a method of stereoselective synthesis, namely (5R ,8S )‐8‐tert‐butyl‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]decane‐2,10‐dione, (1), and (5S ,8R )‐8‐tert‐butyl‐7‐methoxy‐8‐methyl‐9‐oxa‐6‐azaspiro[4.5]decane‐2,10‐dione, (2), both C14H21NO4, were determined by X‐ray diffraction. Both enantiomers crystallize isostructurally in the space group P 21, with one molecule in the asymmetric unit and with the same packing motif. The crystal structures are stabilized by C—H…O hydrogen bonds, resulting in the formation of chains along the [100] and [010] directions. The conformation of the 3,6‐dihydro‐2H‐1,4‐oxazin‐2‐one fragment was compared with other crystal structures possessing this heterocyclic moiety. The comparison showed that the title compounds are not exceptional among structures containing the 3,6‐dihydro‐2H‐1,4‐oxazin‐2‐one fragment. The planar moiety was more frequently observed in derivatives in which this fragment was not condensed with other rings.  相似文献   

16.
Diels‐Alder reactions in a number of air‐ and moisture‐stable dialkylimidazolium halide‐ZnCl2 ionic liquids are reported. High yields and high endo selectivities have been observed. The ionic liquids could then be recyclable without loss of reactivity.  相似文献   

17.
Treatment of 3‐methylamino‐5‐phenylthiophene with α,β‐unsaturated esters, i.e., methyl acrylate, (E)‐methyl crotonate, diethyl fumarate, diethyl maleate and ethyl propiolate, in tetrahydrofuran for several days at reflux gave 1‐methyl‐3,4‐dihydrothieno[2,3‐e]pyridin‐2‐ones 4 and/or 1‐methylthieno[2,3‐e]pyridin‐2‐ones 5 , depending on the structure of the esters. On the other hand, the same reactions with α,β‐unsaturated nitriles such as acrylonitrile and tetracyanoethene, gave the corresponding thiophenes 7 and 10 bearing 2‐cyanoethyl and 1,2,2‐tricyanoethenyl groups at C‐2, respectively. The reaction with (Z)‐1,2‐dicyanoethene under the same conditions produced the corresponding thiophene 9 bearing the 1,2‐dicyanoethenyl group and 1,2‐dicyano‐5‐methylaminobiphenyl.  相似文献   

18.
Four structures of oxoindolyl α‐hydroxy‐β‐amino acid derivatives, namely, methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐methoxy‐2‐phenylacetate, C24H28N2O6, (I), methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐ethoxy‐2‐phenylacetate, C25H30N2O6, (II), methyl 2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐[(4‐methoxybenzyl)oxy]‐2‐phenylacetate, C31H34N2O7, (III), and methyl 2‐[(anthracen‐9‐yl)methoxy]‐2‐{3‐[(tert‐butoxycarbonyl)amino]‐1‐methyl‐2‐oxoindolin‐3‐yl}‐2‐phenylacetate, C38H36N2O6, (IV), have been determined. The diastereoselectivity of the chemical reaction involving α‐diazoesters and isatin imines in the presence of benzyl alcohol is confirmed through the relative configuration of the two stereogenic centres. In esters (I) and (III), the amide group adopts an anti conformation, whereas the conformation is syn in esters (II) and (IV). Nevertheless, the amide group forms intramolecular N—H...O hydrogen bonds with the ester and ether O atoms in all four structures. The ether‐linked substituents are in the extended conformation in all four structures. Ester (II) is dominated by intermolecular N—H...O hydrogen‐bond interactions. In contrast, the remaining three structures are sustained by C—H...O hydrogen‐bond interactions.  相似文献   

19.
A series of nitrile‐functionalized ionic liquids were found to exhibit temperature‐dependent miscibility (thermomorphism) with the lower alcohols. Their coordinating abilities toward cobalt(II) ions were investigated through the dissolution process of cobalt(II) bis(trifluoromethylsulfonyl)imide and were found to depend on the donor abilities of the nitrile group. The crystal structures of the cobalt(II) solvates [Co(C1C1CNPyr)2(Tf2N)4] and [Co(C1C2CNPyr)6][Tf2N]8, which were isolated from ionic‐liquid solutions, gave an insight into the coordination chemistry of functionalized ionic liquids. Smooth layers of cobalt metal could be obtained by electrodeposition of the cobalt‐containing ionic liquids.  相似文献   

20.
Fluorinated phenethyl bromides 1,2 , and 3 , prove to be totally inert under Ritter reaction conditions in the presence of either SnCl4 or AgNO3, due to the strong deactivation by the gem‐difluoro unit. Subjecting 2‐bromo‐1‐fluoro‐1‐phenylethane to SnCl4 in MeCN at elevated temperatures led to formation of 2‐methyl‐4‐phenyl‐4,5‐dihydrooxazole.  相似文献   

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