Synthesis of 2,5 -Bis(4-methyl-2-thienyl)thiophene and 2,5-Bis(4-methyl-2-thienyl)pyrrole

Syntheses of 2,5-bis(4-methyl-2-thienyl)thiophene 3 and 2,5-bis(4-methyl-2-thienyl)pyrrole 4 are described. The key step involves Stetter reaction between 4-methyl-2-thiophenecarboxaldehyde and divinyl sulfone. Cyclizaton of the resulting 1,4-bis-(4-methyl-2-thienyl)-1,4-butanedione 2 with Lawesson's reagent gives 2,5-bis(4-methyl-2-thienyl)thiophene 3, whereas condensation with ammonium acetate provides the 2,5-bis(4-methyl-2-thienyl)pyrrole 4.     

Synthesis and reactions of thiophene sulfides. Communication 40. An unusual reaction of 2,5-bis(methylthio)-3,4-bis(o-hydroxyphenyliminomethyl)thiophene

Conclusions In polar solvents (ethanol and chloroform), 2,5-bis(methylthio)-3,4-bis-(o-hydroxyphenyliminomethyl) thiophene undergoes intramolecular rearrangement to 2,5-bis(methylthio)-3-(2-benzoxazolyl)-4-(o-hydroxyphenylaminomethyl) thiophene.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2750–2753, December, 1985.     

Palladium(II) chloride catalyzes the cross-coupling reaction of 2,5-bis-(butyltelluro)-furan and 1-alkynes

Palladium(II) chloride catalyzed the cross-coupling reaction of 2,5-bis-(butyltelluro) furan and terminal alkynes yielding both symmetrically and unsymmetrically substituted 2,5-bis-acetylenic furan derivatives. The methodology represents a general and efficient protocol for carrying out the synthesis of furan derivatives with potential biological activities.     

Synthesis of 2,5-bis-(Ethynyl) furan Derivatives from 2,5-Furandicarboxaldehyde

A synthesis of the title compounds has been accomplished by conversion of 2,5-furandicarboxaldehyde to the dilithium salt of 2,5-bis-(ethynyl) furan followed by reaction with electrophiles.     

Introduction of ethynylene and thienylene spacers into 2,5-diarylthiazole and 2,5-diarylthiophene

Syntheses of 2,5-diarylthiazole and 2,5-diarylthiophene derivatives bearing ethynylene and thienylene spacers are performed. With the methods for coupling reactions of terminal alkynes and at the CH bond of heteroaromatic compounds, which we have developed, five kinds of thiazole and thiophene derivatives 3-7 are prepared. Spectroscopic characteristics of 3-7 are also measured.     

Synthesis, Mesogenic and Spectroscopic Properties of 2,5-Disubstituted Thiophene Derivatives

Two series of 2,5-disubstituted thiophene derivatives （series 1： 2,5-bis（p-alkoxyphenylethynyl）thiophene and series 2： 2,5-bis[p-（p-alkoxyphenylethynyl）（phenylethynyl）]thiophene） were synthesized and characterized by ^1H NMR, ^13C NMR, HRMS and elemental analysis. The relationship between the structure and the mesogenic and spectroscopic properties has been discussed. The results show that compounds 1a-1f all exhibited an enantiotropic nematic mesophase, which was confirmed by the polarized optical microscopy （POM）, differential scanning calorimeter （DSC） and variable temperature powder X-ray diffraction （PXRD）. In contrast, the extended conjugated analogues 2a-2b had no liquid crystal properties. As for the spectroscopic properties, incorporating more phenylethynyl units results in red-shifted absorption and emission spectra, greatly enhanced quantum efficiency.     

Synthesis of conjugated 2 and 2,5-(ethenyl) and (ethynyl)phenylethynyl thiophenes: fluorescence properties

Nano conjugated thienylethenyl and thienylethynyl compounds with controlled structure and dimensions have been efficiently prepared, by heterocoupling reaction between 1,4-(thienylethynyl)phenylacetylene (or thienylethenyl)phenylacetylene and 2- or 2,5-dihalothiophene. Conjugated 1,4-di(2-thienylethynylphenyl)- (or 2-thienylethenylphenyl)-1,3-butadiyne were obtained by the homocoupling of the terminal acetylenes in excellent yield. The end-capped (N,N-dimethylaminophenyl)- and [3,5-di(trimethylsilylethynyl)-1-ethynyl]-2,5-di(phenylethynyl)_nthiophene were obtained by the heterocoupling between the corresponding terminal acetylene and 2,5-di(iodo)thiophene, catalyzed by the bis(triphenylphosphine)palladium and cuprous iodide system in excellent yield.     

Electrochemical preparation of polythiophene via 2,5-bis(trimethylsilyl)thiophene

Electrochemical polymerization of 2,5-bis(trimethylsilyl) thiophene produced highly conducting films which showed infrared spectra, visible-near infrared absorption spectra, and cyclic voltammograms identical to films prepared from thiophene. Elemental analysis indicated that almost all silicon atoms were eliminated during the electrochemical polymerization. However, scanning electron microscopy showed a morphological difference between the films from 2,5-bis(trimethylsilyl)thiophene and from thiophene. The electrochemical polymerization of bis(2-thienyl)dimethylsilane, 1,2-bis(2-thienyl)tetramethyldisilane, and bis(2-thienyl)diphenylsilane also produced polythiophene films having unique morphologies quite different from the conventional ones. These findings indicate that these electrochemical procedures must be useful for preparation of new conjugated polymers. © 1992 John Wiley & Sons, Inc.     

On the syntheses and some reactions of bis- and tris(methylthio)thiophenes

Reaction between various thienyllithium derivatives and dimethyl disulfide has been used for the preparation of 2,5-, 2,3-, and 3,4-bis(methylthio)thiophenes, as well as 2,3,4- and 2,3,5-tris(methylthio)thiophenes. Bromination of (methylthio)thiophenes with N-bromosuccinimide was found to be most convenient for the preparation of brominated (methylthio)thiophenes such as 3-bromo-2,5-bis(methylthio)- and 5-bromo-2,3-bis(methylthio)thiophene, 3,4-dibromo-2,5-bis(methylthio)-, 2,5-dibromo-3,4-bis(methylthio)- and 2,3-dibromo-4,5-bis(methylthio)thiophene as well as 3-bromo-2,4,5-tris(methylthio)thiophene. The reaction of methylthio substituted thienyllithium derivatives with methyl chloroformate was used for the syntheses of methyl methylthio substituted thiophenecarboxylates and using 1/3 of an equivalent for the direct preparation of methylthio substituted 3-thienylcarbinols as tris[2,4,5-tris(methylthio)-3-thienyl]carbinol.     

Synthesis and polymerization of 2,5-dimethylene-2,5-dihydrothieno[3,2-b]thiophene derivatives: The structure and reactivity of quinonoid monomers

Novel 2,5-dimethylene-2,5-dihydrothieno[3,2-b]thiophene derivatives such as 2,5-bis[di(ethylthio)methylene]-2,5-dihydrothieno[3,2-b]thiophene ( 4b ) and 2,5-bis[cyano(ethylthio)methylene]-2,5-dihydrothieno[3,2-b]thiophene ( 4c ) were successfully synthesized as isolable crystals. Polymerization behavior of 2,5-bis(dicyanomethylene)-2,5-dihydrothieno[3,2-b]thiophene ( 4a ), 4b , and 4c was investigated. 4a , 4b , and 4c are not homopolymerizable with any initiators and also not copolymerizable with vinyl monomers such as styrene (St), methyl methacrylate, and acryronitrile except for an alternating copolymerization of 4a with St. 4a , 4b , and 4c did not copolymerize with 7,8-bis(butoxycarbonyl)-7,8-dicyanoquinodimethane (BCQ) as a highly conjugated comonomer and instead only homopolymer of BCQ was obtained, indicating that they are much less reactive than BCQ. To obtain the relative reactivity among 1c , 2c , and 4c , the rate of addition reaction of 2,2′-azobis(isobutyronitrile) (AIBN) with 4c was compared with those of AIBN with 7,8-bis(ethylthio)-7,8-dicyanoquinodimethane ( 1c ) and with 2,5-bis[cyano(ethylthio)methylene]-2,5-dihydrothiophene ( 2c ) by NMR spectroscopy and analyzed with the first-order kinetics. The relative reactivity among 1c , 2c , and 4c was found to be as follows: 1c > 4c > 2c . The relationship between structure and reactivity for the quinonoid compounds was discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3027–3039, 1999     

Reaction of arylsulfonyl compounds with excess organolithium reagent 10. Opening of the thiophene ring inβ-lithium derivatives of 2,5-bis(tert-butylsulfonyl)thiophene

Conclusions Opening of the thiophene ring is observed in the lithium derivatives of 2,5-bis(t-butylsulfonyl)thiophene, resulting in the formation of functionally substituted dienes of their transformation products.See [1] for communication 9.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1367–1370, June, 1977.     

Reaction of 2,5-(Dibenzothiazolin-2-yl)thiophene with Some Metal Ions

2,5-(Dibenzothiazolin-2-yl)thiophene has been synthesized by the reaction of 2,5-thiophenedicarboxaldehyde and $\text{o}$-aminobenzenethiol. It reacts as a neutral ligand with Pd(II). However, it reacts as a dianion with Cu(II), Ag(I), Cd(II), Pb(II) and Zn(II), suggesting that the ligand is bonded as the conjugate base of the Schiff base 2,5-thiophenediylbis{N-(pheylen-2-thiol)aldimine}. Its behavior with Hg(II), Ru(III), Pt(II), Rh(III) and Ni(II) involves the opening of one of the thiazoline rings of the ligand.     

Synthesis of photochromic bisfulgimides by the condensation of (3<Emphasis Type="Italic">Z</Emphasis>)-3-[1-(2,5-dimethyl-3-thienyl)-ethylidene]-4-isopropylidene-2,5-furandione with aromatic diamines

The first representatives of thiophene derivatives with two fulgimide fragments in one molecule have been obtained by the condensation of (3Z)-3-[1-(2,5-dimethyl-3-thienyl)ethylidene]-4-isopropylidene-2,5-furandione with aromatic diamines. The photochromic properties of the obtained compounds have been investigated and the effect of a spacer, linking the two fulgimide fragments, on the reaction rates of photocoloration and photodecoloration of these compounds has been studied.     

Unconventional reactivity of epichlorohydrin in the presence of triphenylphosphine: isolation of ((1,4-dioxane-2,5-diyl)-bis-(methylene))-bis-(triphenylphosphonium) chloride

Research on Chemical Intermediates - The selective formation of the heterocyclic salt ((1,4-dioxane-2,5-diyl)-bis-(methylene))-bis-(triphenylphosphonium) chloride was observed when epichlorohydrin...     

2,5-二(2-氨基乙氧甲基)噻吩合成及抑菌活性

噻吩烷基胺及其衍生物对疟疾、麻风、真菌、病毒和某些肿瘤均有较强的药理活性[1～ 2 ] ,因此合成和开发这类新物质具有重要的意义。以前 ,由 2 噻吩甲醛合成的噻吩类衍生物药物较多[3] ,但对噻吩双取代衍生物的合成研究还未引起重视。因此 ,为了探索这类化合物的性质和抑菌效果。我们合成了未见文献报道的 2 ,5 二 ( 2 氨基乙氧甲基 )噻吩 ,通过多种测试手段 ,确定了它的组成结构 ,其合成路线如下 :1　实验部分1 1　仪器与试剂Ｎｉｃｏｌｅｔ1 70Ｓ红外光谱仪 (ＫＢｒ压片 ) ,ＰＥ 2 4 0Ｃ型元素分析仪 ,ＥＭ 360 60ＭＨｚ核磁共振仪。…     

Structure and properties of poly(2,5-dimethylterephthalamides)

Six methyl-substituted wholly aromatic polyamides were synthesized from the reaction of 2,5-dimethylterephthaloyl chloride with p-phenylenediamine, its 2,5-dimethyl and 2-methyl derivatives, m-phenylenediamine, or its 2-methyl and 4-methyl derivatives by solution polycondensation at low temperature. The x-ray diffraction diagrams of the polyamides obtained exhibit crystal patterns. Density values range from 1.26 to 1.37 g/cm³. NMR spectra determined in concentrated H₂SO₄ solution are reported. Poly(2,5-dimethylterephthalamides) have lower thermal stability than the corresponding polyterephthalamides. The increase in solubility of polyamide by the introduction of the 2,5-dimethylterephthaloyl linkage is accompanied by a decrease in thermal stability. The effect of methyl substituents on thermal properties and solubility is discussed in terms of the packing of polymeric molecules and the extent of hydrogen bonding of the amide groups.     

Thiophene 1-oxides. V. Comparison of the crystal structures and thiophene ring aromaticity of 2,5-diphenylthiophene,its sulfoxide and sulfone

The detailed preparation of 2,5-diphenylthiophene 1-oxide (2) is reported as well as the comparative study of the crystal structures of 2,5-diphenylthiophene, 1 , its sulfoxide 2 and sulfone 3 obtained by X-ray diffraction. This work represents the first experimental study of a complete heterocyclic series, including a thiophene derivative, and the corresponding sulfoxide and sulfone. On the basis of the geometrical parameters, the first unequivocal experimental parameters obtained for a thiophene 1-oxide derivative, we have also examined the evolution of the aromatic character of the thiophene ring when oxidizing the sulfur atom to the sulfoxide and the sulfone. Paolini's bond orders and Julg and Francois's aromaticity indices have also been calculated for the three compounds and compared to those previously calculated for related thiophene derivatives by semi-empirical or ab initio methods [6], [7]. All the data examined showed that, in spite of its non planarity, the thiophene ring of 2,5-diphenylthiophene 1-oxide 2 could still exhibit some de localization of its p electrons indicating a certain degree of aromaticity lower than in thiophene 1 but higher than in the sulfone 3 .     

Benzylidène-5-hydroxy-4-dihydro-2,5-thiophènecarboxanilides-3-(Z): Synthèse et isomérisation en benzyl-5-hydroxy-4-thiophènecarboxanilides-3

(Z)-5-Benzylidene-2,5-dihydro-4-hydroxy-3-thiophenecarboxanilides: Synthesis and Isomerization into 5-Benzyl-4-hydroxy-3-thiophenecarboxanilides Upon treatment with an arylamine in boiling xylene, the esters I yield predominantly the corresponding anilides II, along with a small but variable amount of the isomeric thiophene derivatives III (Table 1). On the other hand, the derivatives III can be readily prepared by base- or acid-catalyzed isomerization of II . Esters I can also be isomerized to the corresponding thiophene derivatives IV (Scheme 6), but only in the presence of a strong acid (Table 4). The two series of isomers reported in Tables 2 and 3 present spectral differences which allow unambiguous structural assignments. The (Z)-configuration for compounds of Table 2 is confirmed by a NOE study carried out on the O-methyl derivatives 6a and 7a .     

Synthesis and comparative study of the heterocyclic rings on liquid crystalline properties of 2,5-aryl-1,3,4-oxa(thia)diazole derivatives containing furan and thiophene units

A series of heterocyclic liquid crystalline compounds containing 1,3,4-oxadiazole/thiadiazole, furan and thiophene units were synthesised and characterised by means of electrospray ionisation-mass spectrometry (ESI-MS), high-resolution mass spectroscopy (HRMS), ¹H nuclear magnetic resonance (NMR) and ¹³C NMR. The thermal behaviours were investigated by differential scanning calorimetry (DSC) and polarised optical microscopy (POM). The effect of the 1,3,4-oxadiazole, 1,3,4-thiadiazole, furan, thiophene and benzene rings on the liquid crystalline properties was discussed briefly in context with the geometrical and electronic factors. The results showed that the tendency to form mesophases follows the sequence: 1,4-disustituted benzene >2,5-disubstituted thiophene >2,5-disustituted furan and 1,3,4-thiadiazole >1,3,4-oxadiazole.     

2,5-Dimethoxy-2,5-dihydrofuran chemistry: a new approach to 2(5H)-furanone derivatives

2,5-Dimethoxy-2,5-dihydrofuran is a synthetic equivalent of 2(5H)-furanone or 2-trimethylsilyloxyfuran, useful C₄ synthons in the preparation of 5-substituted-2(5H)-furanone derivatives. The reaction conditions adopted allow to obtain different classes of complex and biologically interesting compounds, in only one step, with high yields.