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1.
Hydromagnesiation of alkynylsilanes 1 in diethyl ether gave (Z)‐α‐silylvinyl Grignard reagents 2 , which reacted with arylsulfenyl chlorides 3 to afford stereoselectively (E)‐α‐silylvinyl sulfides 4 in good yields. (E)‐α‐Silylvinyl sulfides 4 could undergo the cross‐coupling reactions with Grignard reagents in the presence of NiCl2(PPh3)2 to give stereoselectively (Z)‐1,2‐disubstituted vinylsilanes 5 . © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:644–647, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20165  相似文献   

2.
The toxicity studies of free 5‐[(E)‐2‐(aryl)‐1‐diazenyl]‐2‐hydroxybenzoic acid and 2‐[(E)‐2‐(3‐formyl‐4‐hydroxyphenyl)‐1‐diazenyl]benzoic acid and their tri‐n‐butyltin(IV) complexes were evaluated by using sea urchin early developmental stages as recommended model organisms for toxicity tests. The novel complexes, as the parent tri‐n‐butyltin(IV) chloride (TBTCl), caused mitosis block and induced high embryonic mortality in sea urchin. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

3.
The synthesis and polymerization of (E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene was carried out with a homogeneous vanadium acetylacetonate/aluminum triethyl catalyst system, a bis(rhodium chloride cycloocta‐1,5‐diene) complex, and a palladium/trimethylsilyl complex. In all cases, the main fraction was a polymer with a stereoregular structure. The polymerization with the vanadium catalyst gave a polymer fraction in a low yield. The polymerization of (E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene with the soluble rhodium complex gave a polymer in a high yield. The soluble palladium/chlorotrimethylsilane complex gave a polymer in a good yield. On the basis of the spectroscopic data, the poly{(E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene)} obtained, in all cases, showed a cis–transoidal stereoregular structure. The molecular mass of poly{(E)‐p‐[(p‐methoxyphenyl)‐2‐ethenyl]phenylacetylene)} was determined by the matrix‐assisted laser desorption/ionization time‐of‐flight technique. The kinetics of the reaction were analyzed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6438–6444, 2005  相似文献   

4.
(E)‐β‐Iodoenamides and (E)‐β‐iodoenimides can be easily obtained from N‐vinyl derivatives (N‐vinylamides and N‐vinylimides) by stereoselective ruthenium‐catalysed silylative coupling with vinyltrimethylsilane (Marciniec coupling) and subsequent stereospecific silicon–iodine exchange. Bromodesilylation of (E)‐β‐silylenimides affords (E)‐β‐bromoenimides, while the analogous reactions involving (E)‐β‐silylenamides lead to decomposition of substrates. N‐Halosuccinimides have been found as the most effective halogenating agents in the desilylation step under mild conditions. The ruthenium‐catalysed silylation/halodesilylation sequence can be performed in a one‐pot procedure. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

5.
Diels–Alder reactions of 5‐[methoxypoly(oxyethylene)]‐(3E)‐1,3‐pentadiene ( 1a ) with maleic anhydride, diethyl acetylenedicarboxylate (DADC), and acrolein were investigated for the synthesis of new poly(ethylene glycol) derivatives. To facilitate the characterization of the derivatives, Diels–Alder reactions of 5‐methoxyethoxy‐(3E)‐1,3‐pentadiene ( 1b ) with the aforementioned dienophiles were also studied. The reaction of o‐toluidine with the cycloaddition product from maleic anhydride and 1b resulted in the corresponding amide products. The reactions of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone with cycloadducts derived from 1a and 1b with DADC resulted in the aromatization of the corresponding products. An NMR analysis of the adducts obtained from 1a and acrolein in water and from 1b and acrolein in water/acetonitrile (4:1 v/v) indicated a mixture of endo and exo, with the endo concentration being approximately 80%. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1895–1902, 2005  相似文献   

6.
Highly selective synthesis of 1‐substituted (E)‐buta‐1,3‐dienes via palladium‐catalyzed Suzuki–Miyaura cross‐coupling of (E)‐alkenyl iodides with 4,4,5,5‐tetramethyl‐2‐vinyl‐1,3,2‐dioxaborolane ( 1 ) is reported. The vinylboronate pinacol ester ( 1 ) acts as a vinyl building block to show high chemoselectivity for the Suzuki–Miyaura pathway versus Heck coupling in the presence of biphasic conditions (Pd(PPh3)4, aqueous K2CO3, toluene and ethanol). Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

7.
The compound comprises a 1Z,3E‐butadiene moiety substituted by two pinacol boronate functional groups. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

8.
Tin–lithium exchange reaction of (E)‐α‐stannylvinyl sulfides 1 with n‐butyllithium gave (Z)‐α‐arylsulfanylvinyllithiums 2 , which reacted with aldehydes or ketones 3 to afford stereoselectively (2Z)‐2‐arylsulfanylallylic alcohols 4 in good to high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:639–643, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20487  相似文献   

9.
Chloroformylation of 5,5‐dimethyl‐1,2‐ oxathiolan‐4‐one 2,2‐dioxide 4 with Vilsmeier reagent (DMF/POCl3) led to the formation of cyclic β‐chloro‐vinylaldehyde (4‐chloro‐5,5‐dimethyl‐3‐formyl‐1,2‐oxathiolene 2,2‐dioxide 5 ). Compound 5 reacted with formamidine, o‐aminophenol, 1,2‐phenylenediamine, aminopyrazole, and aminotetrazole to give the corresponding heterocyclic compounds. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:200–204, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20094  相似文献   

10.
Stereospecific synthesis of a family of novel (E)‐2‐aryl‐1‐silylalka‐1,4‐dienes or (E)‐4‐aryl‐5‐silylpenta‐1,2,4‐trienes via a cross‐coupling of (Z)‐silyl(stannyl)ethenes with allyl halides or propargyl bromide is described. In the reaction with allyl bromide, either a Pd(dba)2? CuI combination (dba, dibenzylideneacetone) in DMF or copper(I) iodide in DMSO–THF readily catalyzes or mediates the coupling reaction of (Z)‐silyl(stannyl)ethenes at room temperature, producing novel vinylsilanes bearing an allyl group β to silicon with cis ‐disposition in good yields. Allyl chlorides as halides can be used in the CuI‐mediated reaction. CuI alone much more effectively mediates the cross‐coupling reaction with propargyl bromide in DMSO–THF at room temperature compared with a Pd(dba)2? CuI combination catalysis in DMF, providing novel stereodefined vinylsilanes bearing an allenyl group β to silicon with cis ‐disposition in good yields. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

11.
Annulenoid Tetrathiafulvalenes: 5,16‐Bis(1,3‐benzodithiol‐2‐ylidene)‐5,16‐dihydrotetraepoxy‐ and 5,16‐Bis(1,3‐benzodithiol‐2‐ylidene)‐5,16‐dihydrotetraepithio[22]annulenes(2.1.2.1) The title compounds are among the first tetrathiafulvalenes with annulene spacers, here with tetraepoxy‐[22]annulene(2.1.2.1) (see 3a ), tetraepithio[22]annulene(2.1.2.1) (see 3b ), and diepithiodiepoxy[22]annulene(2.1.2.1) (see 23 ) units. The annulenoid tetrathiafulvalenes 3a and 3b are prepared by cyclizing McMurry coupling of the 5,5′‐(1,3‐benzodithiol‐2‐ylidenemethylene)bis[furan‐ or thiophene‐2‐carbaldehydes] ( 8a or 8b , resp.) or by Wittig reaction of (1,3‐benzodithiol‐2‐yl)tributylphosphonium tetrafluoroborate ( 13b ) with tetraepoxy[22]annulene(2.1.2.1)‐1,12‐dione 20 (formation of 3a ) or diepithiodiepoxy[22]annulene(2.1.2.1)‐1,12‐dione 22 (formation of 23 ). The annulenoide tetrathiafulvalene 3a is obtained as a mixture of the isomers (E,E)‐ and (Z,Z)‐ 3a . At 130°, (Z,Z)‐ 3a rearranges quantitatively into the (E,E)‐isomer. Isomer (E,E)‐ 3a is a dynamic molecule, where the (E)‐ethene‐1,2‐diyl bridges rotate around the adjacent σ‐bonds. The tetraepithioannulene derivative 3b as well as 23 only exist in the (Z,Z)‐configuration. The oxidation of (E,E/Z,Z)‐ 3a with Br2 yields the annulene‐bridged tetrathiafulvalene dication (E,E)‐ 3a Ox, while with 4,5‐dichloro‐3,6‐dioxocyclohexa‐1,4‐diene‐1,2‐dicarbonitrile (DDQ) obviously only the radical cation 3a Sem is formed, which belongs to the class of cyanine‐like violenes. The annulenoide tetrathiafulvalenes 3b and 23 , which exist only in the (Z,Z)‐configuration, obviously for steric reasons, cannot be oxidized by DDQ. Electrochemical studies are in agreement with these results.  相似文献   

12.
Useful oxidation reaction of 2‐alkyl(aryl)‐3‐methylthiopyrano[4,3‐c]pyrazol‐4(2H)‐ones, leading to either the corresponding sulfoxides or sulfones, using hydrogen peroxide and acetic acid in 1,2‐dichloroethane, is described. Bioassay results showed that the products have some herbicidal activity. © 2005 Wiley Periodicals, Inc. 16:255–258, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20067  相似文献   

13.
Bis((Z)‐5‐phenyl‐2‐phenylmethylidene‐1, 3‐dithiole‐4‐yl)monosulfane ( 6 ), a molecule consisting of two diphenyldithiafulvene units connected by a sulfur bridge, was synthesized by the selective lithiation of (Z)‐4‐phenyl‐2‐phenylmethylidene‐1, 3‐dithiole ( 7a ) at the endocyclic double bond and by subsequent reaction of the lithiated intermediate with bis(phenylsulfonyl)sulfane. Since this reaction sequence proceeded with retention of configuration, of three possible isomers (E, E, Z, E, and Z, Z) only the Z, Z form was obtained. On the basis of the X‐ray structure analysis and the NMR‐spectroscopic characterization of 6 supplemented by the NMR parameters of (E)‐ and (Z)‐4‐phenyl‐2‐phenylmethylidene‐1, 3‐dithiole, it was demonstrated that two characteristic 5J coupling constants of the proton at the exocyclic double bond indicate the configuration (Z or E) of disubstituted dithiafuvene derivatives.  相似文献   

14.
The reaction of the 4‐hydroxyquinoline‐3‐carboxylate 6 with pentaerythritol tribromide gave the 1,1′‐(2‐methylenepropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 11 , whose reaction with bromine afforded the 1,1′‐(2‐bromo‐2‐bromomethylpropane‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 12 . Compound 12 was transformed into the (Z)‐1,1′‐(2‐acetoxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylate) 13 or (E)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylate) 14 . Hydrolysis of the dimer (Z)‐ 13 or (E)‐ 14 with potassium hydroxide provided the (E)‐1,1′‐(2‐hydroxymethylpropene‐1,3‐diyl)di(4‐quinolone‐3‐carboxylic acid) 15 or (Z)‐1,1′‐[2‐(imidazol‐1‐ylmethyl)propene‐1,3‐diyl]di(4‐quinolone‐3‐carboxylic acid) 16 , respectively. The nuclear Overhauser effect (NOE) spectral data supported that those hydrolysis resulted in the geometrical conversion of (Z)‐ 13 into (E)‐ 15 or (E)‐ 14 into (Z)‐ 16 .  相似文献   

15.
A Pd(dba)2–P(OEt)3 combination allowed the silastannation of arylacetylenes, 1‐hexyne or propargyl alcohols with tributyl(trimethylsilyl)stannane to take place at room temperature, producing (Z)‐2‐silyl‐1‐stannyl‐1‐substituted ethenes in high yields. Novel silyl(stannyl)ethenes were fully characterized by 1H‐, 13C‐, 29Si‐ and 119Sn‐NMR as well as infrared and mass analyses. Treatment of a series of (Z)‐1‐aryl‐2‐silyl‐1‐stannylethenes and (Z)‐1‐(3‐pyridyl)‐2‐silyl‐1‐stannylethene with hydrochloric acid or hydroiodic acid in the presence of tetraethylammonium chloride (TEACl) or tetrabutylammonium iodide (TBAI) led to the exclusive formation of (E)‐trimethyl(2‐arylethenyl)silanes with high stereoselectivity. A similar reaction of (Z)‐1‐(2‐anisyl)‐2‐silyl‐1‐stannylethene also produced E‐type trimethyl[2‐(2‐anisyl)ethenyl]silane, while (Z)‐trimethyl [2‐(2‐pyridyl)ethenyl]silane was produced exclusively from (Z)‐1‐(2‐pyridyl)‐2‐silyl‐1‐stannylethene. Protodestannylation of (Z)‐1‐[hydroxy(phenyl)methyl]‐2‐silyl‐1‐stannylethene with trifluoroacetic acid took place via the β‐elimination of hydroxystannane, providing trimethyl(3‐phenylpropa‐1,2‐dienyl)silane quite easily. The destannylation products were also fully characterized. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

16.
An (E)/(Z) mixture (3 : 2) of 7‐benzylidenecycloocta‐1,3,5‐triene ( 5 ) is obtained when 1‐benzylcycloocta‐1,3,5,7‐tetraene ( 7 ), prepared by an improved procedure, is treated with t‐BuOK in THF. Alternatively, a ca. 9 : 1 mixture (E)/(Z)‐ 5 can be prepared in a Wittig reaction involving benzaldehyde and cycloocta‐2,4,6‐trien‐1‐ylidenetriphenylphoshorane ( 9 ). Treatment of (E)/(Z)‐ 5 88 : 12 with ethenetetracarbonitrile (TCNE) gave a complex mixture of products, from which seven mono‐adducts and two bis‐adducts were isolated (Sect. 2.2.1). Of the mono‐adducts, four are π4+π2 adducts: two ((E)‐ and (Z)‐isomers) are derived from valence tautomers of the two isomers of (E)/(Z)‐ 5 , while it is tentatively suggested that the other two (again (E)‐ and (Z)‐isomers) are formed from the intermediacy of a pentadienyl zwitterion (Sect. 2.3). The remaining three mono‐adducts, two of which are epimers, are π8+π2 adducts. It is suggested that they are derived from the intermediacy of homotropylium zwitterions (Sect. 2.3). For the two bis‐adducts, it is postulated that they are derived from an initial π2+π2 cycloaddition involving the homotropylium zwitterions followed by π4+π2 cycloaddition to the valence tautomer of each of the π2+π2 cycloadducts. With 4‐phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione ( 6 ), (E)/(Z)‐ 5 91 : 9 yielded two π4+π2 cycloadducts ((E)‐ and (Z)‐isomers) as well as two epimeric π8+π2 cycloadducts (Sect. 2.2.2). The intermediacy of pentadienyl (tentative suggestion) and homotropylium zwitterions accounts for the formation of the products (Sect. 2.3).  相似文献   

17.
Methyl (2E,4R)‐4‐hydroxydec‐2‐enoate, methyl (2E,4S)‐4‐hydroxydec‐2‐enoate, and ethyl (±)‐(2E)‐4‐hydroxy[4‐2H]dec‐2‐enoate were chemically synthesized and incubated in the yeast Saccharomyces cerevisiae. Initial C‐chain elongation of these substrates to C12 and, to a lesser extent, C14 fatty acids was observed, followed by γ‐decanolactone formation. Metabolic conversion of methyl (2E,4R)‐4‐hydroxydec‐2‐enoate and methyl (2E,4S)‐4‐hydroxydec‐2‐enoate both led to (4R)‐γ‐decanolactone with >99% ee and 80% ee, respectively. Biotransformation of ethyl (±)‐(2E)‐4‐hydroxy(4‐2H)dec‐2‐enoate yielded (4R)‐γ‐[2H]decanolactone with 61% of the 2H label maintained and in 90% ee indicating a stereoinversion pathway. Electron‐impact mass spectrometry analysis (Fig. 4) of 4‐hydroxydecanoic acid indicated a partial C(4)→C(2) 2H shift. The formation of erythro‐3,4‐dihydroxydecanoic acid and erythro‐3‐hydroxy‐γ‐decanolactone from methyl (2E,4S)‐4‐hydroxydec‐2‐enoate supports a net inversion to (4R)‐γ‐decanolactone via 4‐oxodecanoic acid. As postulated in a previous work, (2E,4S)‐4‐hydroxydec‐2‐enoic acid was shown to be a key intermediate during (4R)‐γ‐decanolactone formation via degradation of (3S,4S)‐dihydroxy fatty acids and precursors by Saccharomyces cerevisiae.  相似文献   

18.
Poly(p‐phenylenevinylene) (PPV) and its derivatives exhibit strong luminescence, being serious candidates to be used as active layers in organic light‐emitting diodes. However, the structural degradation caused by photo‐oxidation is an obstacle for commercial applications of such materials. Here, we show that spectroscopy ellipsometry is a useful technique to investigate the photo‐oxidation of poly[(2‐methoxy‐5‐hexyloxy)‐p‐phenylenevinylene] (MH‐PPV), a PPV derivative, which emits a red color light. Spectroscopy ellipsometry enables determination of the complex dielectric function—?*(E)—of MH‐PPV thin‐layer films exposed to air, in the 2.1–4.2 eV energy range, as a function of the light exposure time (te). By using the Lorentz model to fit the experimental ?*(E) curves, it was inferred that the interactions among polymeric chains increase with te. From ?*(E), it is also possible to obtain the complex refractive index, N*(E) = n + ik. At higher energies (where k ? n), n increases from 1.32 to 1.40 with the photo‐oxidation progress. The behavior of n was investigated by using the Lorenz–Lorentz equation, taking into account the contribution for n by the chromophores of MH‐PPV. The effect of photo‐oxidation, mainly due to the replacement of vinyl C?C by the ketone C?O bonds, is confirmed by Fourier transform infrared measurements, an effect that reduces the average effective polymer conjugation length. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1033–1041, 2004  相似文献   

19.
The steady‐state and time‐resolved photoluminescence (PL), electrochemical behavior, and electroluminescence (EL) of didodecyloxy poly(p‐phenylenevinylene)‐based polymers that contained along the backbone structure 1,3,5‐triphenylbenzene (PC) or 2,4,6‐triphenylpyridine (PN) were studied. An intensive green PL broad‐band emission with maxima at 516 and 527 nm was observed from thin films of PC and PN polymers, respectively, redshifted in comparison with the PL emission spectra measured in tetrahydrofuran solutions. The PL decay dynamics revealed the existence of more than one excited species, and the decay curves were best described by three‐term exponential functions with a dominant lifetime of about 1 ns. The results of time‐resolved PL and steady‐state PL studies indicated excimer or aggregate formation. Both polymers oxidized irreversibly. A quasireversible reduction was observed in the PN polymer, whereas the PC polymer reduced irreversibly. For PC, slightly higher values of the ionization potential (EIP) and electron affinity (EA) were found (EIP = 5.52 eV, EA = 2.85 eV) than those for PN (EIP = 5.37 eV, EA = 2.77 eV). Light‐emitting devices with indium tin oxide hole‐injecting and aluminum electron‐injecting electrodes were prepared and studied. They emitted green light, and their EL spectra were similar to those of PL thin films. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 524–533, 2006  相似文献   

20.
胡荣华  陈桂琴  蔡明中 《中国化学》2007,25(12):1927-1931
(E)-α-Stannylvinyl phenyl(or p-tolyl)sulfones underwent an iododestannylation reaction to afford (E)-α-iodovinyl phenyl(or p-tolyl)sulfones 1, which reacted with (E)-alkenylzirconium(IV) complexes 2 produced in situ by hydrozirconation of terminal alkynes in the presence of a Pd(PPh3)4 catalyst to afford stereoselectively (1Z,3E)-2- phenyl(or p-tolyl)sulfonyl-substituted 1,3-dienes 3 in good yields.  相似文献   

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