基于GC/Q-TOF MS技术鉴定S-zorb汽油中噻吩类化合物

结合气相色谱分离技术和MS/MS串联质谱筛查技术,通过选定目标母离子进行碰撞诱导解离,获取精确质量子离子信息,实现汽油馏分中噻吩类化合物的痕量筛查分析.选取5种不同碳数取代噻吩类化合物作为标准物绘制定量标准曲线,建立了基于气相色谱-四极杆串联飞行时间质谱(GC/Q-TOF MS)直接测定汽油中噻吩类化合物的方法.利用该...     

Nitro derivatives of 2-(1-naphthyl) thiophene

2-[1-(3, 4-Dihydronaphythyl)]thiophene, 2-(1-naphthyl)thiophene, 3, 4, 5-triacetoxymercuri-, 3, 4-diacetoxymercuri-5-nitro-, 4, 5-diacetoxymercuri-3-nitro-2-(1-naphthyl)thiophenes and 3, 3, 4-triacetoxymercuri-2[1-(4-nitronaphthyl)]thiophene are synthesized and characterized. Nitration of 2-(1-naphthyl)thiophene with copper nitrate in acetic anhydride leads to formation of two isomeric mono-nitro derivatives, 4-nitro- and 5-nitro-2-(1-naphthyl)thiophene.     

Mass spectra of new heterocycles: XVI. Electron impact study of alkyl 5-aminothiophene-2-carboxylates

Electron impact mass spectra of alkyl 4-alkoxy-5-amino-3-methylthiophene-2-carboxylates were studied for the first time. These compounds, except for 4-(1-ethoxyethoxy) and 4-(ferrocenylmethoxy) derivatives, give rise to a stable molecular ion whose decomposition follows three pathways. The main fragmentation pathway of the molecular ion is elimination of alkyl radical from the 4-alkoxy group, the second pathway involves expulsion of alkoxy group from the ester moiety, and the third pathway is decomposition of the thiophene ring. The molecular ions of 4-(1-ethoxyethoxy)thiophenes decompose mainly via elimination of ethyl vinyl ether molecule with formation of [M–VinOEt]⁺ · odd-electron ion, and fragmentation of the latter follows general pathways. In the mass spectra of 4-(ferrocenylmethoxy)thiophenes the most abundant are ferrocenylmethyl ion with m/z 199 (I _rel 100%) and fragment ions derived therefrom.     

REACTIONS OF THIOPHENES AND ACETYLENES IN POLAR AND APOLAR SOLVENTS

Abstract

Although the aromatic 6π-electron system of thiophenes is rather unreactive in cycloaddition reactions we have found that several thiophene derivatives react with acetylenes. Alkylthiophenes undergo (2+2)-cycloaddition reactions with electron-deficient acetylenes in apolar solvents in the presence of Lewis acids to give 2-thia-bicyclo [3. 2. 0] hept-3, 6-dienes (1). These compounds show isomerization via an a, a-Cope rearrangement at temperatures of 100 to 150°C.     

Synthesis and structure of derivatives of 7-oxo-4,5,6,7-tetrahydrobenzo[b]-thiophene and 7-hydroxybenzo[b]thiophene

The oxidation of 2-acylamino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophenes gave the corresponding 7-oxotetrahydrobenzo[b]thiophenes and some of the transformations of these compounds were studied. These compounds were used for the synthesis of 3-ethoxycarbonyl-6-bromo-7-hydroxybenzo[b]thiophene. The structures of the compounds prepared were established by chemical and spectral methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1626–1629, December, 1984.     

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 electrochemical investigation of <Emphasis Type="Italic">beta</Emphasis>-substituted thiophene-based donor–acceptor copolymers with 3,4-ethylenedioxythiophene (EDOT)

The present work reports the synthesis of four electron-acceptor beta-substituted thiophenes that were studied as monomers for electrochemical polymerization with 3,4-ethylenedioxythiophene (EDOT), an electron-donating monomer, aiming the combination of electron-acceptor and donor monomer thiophene to a simpler and convenient build up of novel donor–acceptor copolymeric materials via electrochemical polymerization. Four novel copolymers poly(EDOT-co-3-thiophene phenylacetate), (PEDOT-co-PPhTAc-2a), poly(EDOT-co-3-thiophene(4-nitrophenyl)acetate) (PEDOT-co-PPhTAc-2b), poly(EDOT-co-3-thiophenephenylcarboxylate) (PEDOT-co-PPhTCb), and poly(EDOT-co-3-(phenoxymethyl)thiophene) (PEDOT-co-PPhOMT) were electrochemically polymerized. The monomers were characterized by spectrometric techniques (FTIR, ¹H NMR, and ¹³C NMR), and the copolymers were identified by electrochemical analyses and FT-IR. Although the corresponding homopolymers could not be obtained, in the presence of EDOT, the copolymers were formed in a quasi-reversible electrochemical kinetics. The infrared spectra of the copolymers as well the electrochemical profile corroborates their obtaining. The mass variation during the electrosynthesis was analyzed using a quartz crystal microbalance. The film’s morphologies were investigated by SEM. Interestingly, the combination of electron-rich monomer thiophene (EDOT) and these electron-deficient carboxy-substituted thiophenes might be a convenient building block couple to increase the performance control of physic-chemical properties of mixed polythiophenes with innovative applications and they also showed a possible applicability as charge storage device.     

Palladium-catalysed direct 3- or 4-arylation of thiophene derivatives using aryl bromides

The palladium-catalysed direct 3- or 4-arylation of 2,5-disubstituted thiophenes using aryl bromides gives a simple access to a variety of 3- or 4-arylthiophene derivatives. Moderate to good yields of 3-arylated thiophenes were obtained using 2,5-dimethylthiophene. In the presence of unsymmetrically disubstituted, 2-acetyl-5-methylthiophene, a regioselective arylation on carbon 4 of thiophene was observed. This reaction provides only HX associated to the base as by-product and reduces the number of steps to prepare these compounds.     

Substituent effects on the thermochemistry of thiophenes. a theoretical (G3(MP2)//B3LYP and G3) study

Very good linear correlations between experimental and calculated enthalpies of formation in the gas phase (G3(MP2)//B3LYP and G3) for 48 thiophene derivatives have been obtained. These correlations permit a correction of the calculated enthalpies of formation in order to estimate more reliable "experimental" values for the enthalpies of formation of substituted thiophenes, check the reliability of experimental measurements, and also predict the enthalpies of formation of new thiophenes that are not available in the literature. Moreover, the difference between the enthalpies of formation of isomeric thiophenes with the same substituent in positions 2 and 3 of the ring has been analyzed. Likewise, a comparison of the substituent effect in the thiophene and benzene rings has been established.     

Regioselective synthesis of 2,4-disubstituted thiophenes

A highly regioselective route was established to 2-aryl-, 2-cyclohexyl-, and 2-(2-arylethyl)4-alkylthiophenes, which are potential candidates as liquid crystalline compounds of low viscosity. The key synthetic intermediates, 2-substituted-4-(chloromethyl)thiophenes 6, 14, and 20 were prepared respectively from the reactions of β, γ-epoxycarbonyl compounds 5, 13, and 19 with Lawesson's reagent in the presence of a catalytic amount of p -toluenesulfonic acid. The epoxycarbonyl compounds were obtained from the TiCl₄-mediated reactions of 2-(chloromethyl)-3-(trimethylsliyl)propene (10) with acid chlorides followed by epoxidation with m-chloroperoxybenzoic acid, or from prior epoxidation followed by oxidation with pyridinium dichromate of homoallylic alcohols 3. The homoallylic alcohols 3 were synthesized from the reactions of 2-(chloromethyl)-3-(trichlorosilyl)propene (2) with aldehydes in N, N-dimethylformamide. Copper (I) catalysed cross-coupling reactions of 2-substituted-4-(bromomethyl)thiophenes (which were prepared by transhalogenation of 2-substituted-4- (chloromethyl)thiophenes with NaBr in acetone) with Grignard reagents afforded 2,4-disubstituted thiophenes. Using this method, eleven 2,4-disubstituted thiophenes were synthesized and their potentials as liquid crystalline compound of low viscosity were examined. The synthesized 2-(4-cyanophenyl)-4-pentylthiophene was observed to have a lower melting point than the corresponding 2,5-disubstituted thiophene. This observation is consistent with the expectation from the basis of molecular linearity which can affect the viscosity and/or melting point of crystalline compounds.     

两种非对称芳基二噻吩并[2,3-b:3',2'-d]噻吩的合成与光谱特性

合成了两种非对称芳基取代的并三噻吩化合物.以2-溴-5-三甲基硅-二噻吩并[2,3-b:3',2'-d]噻吩为原料,经脱除四甲基硅烷(TMS)和Suzuki偶联两步反应制备了2-噻吩基二噻吩并[2,3-b:3',2'-d]噻吩,总产率为67.4%;以2-苯基二噻吩并[2,3-b:3',2'-d]噻吩为原料,经N-溴代琥...     

Synthesis of 3,4-Biheterylthieno[2,3-b]-thiophenes. Part I: Synthesis of 3,4-Bi(1′,3′,4′-thiadiazolyl-, s-triazolyl-,1′,3′,4′-thiadiazinyl-, 1′,3′,4′-triazinyl-, thiazolyl-, 1′,3′-thiazinyl- and primidinyl)-thieno[2,3-b]thiophenes

3,4-Diamino-2,5-dicarbethoxythieno[2,3-b]thiophene ( 1 ) was allowed to react with NaNO 2 and active methylenes to afford the corresponding azo compounds 2a-c . Hydrazonyl chloride 2a was treated with carbon disulfide, phenyl isothiocyanate, benzonitrile, benzyl cyanide, malononitrile, benzalaniline, ethyl mercaptoacetate, and ethyl glycinate to give 1,3,4-thiadiazolyl-, s-triazolyl-, 1,3,4-thiadiazinyl-, 1,3,4-triazinylthieno[2,3-b]thiophenes 3-6 respectively. The reaction of 2b,c with urea, thiourea, and guanidine afforded pyrimidinyl- and thiazinylazothieno [2,3-b]thiophenes 7-10 respectively. Bithiazolylthieno[2,3-b]thiophenes 11 and 13 were synthesized by treating compound 1 with CS 2 along with halo compounds. The addition of S,S-, N,S-, and N,O-acetals to the Schiff base 14 afforded compounds 15-17 respectively.     

Synthesis and Characterization of a New Series of Hydroxy Pyrazolines

3-Phenyl-1-(thiophen-2-yl)prop-2-en-1-one obtained by Claisen–Schmidt condensation of 2-acetyl thiophene with benzaldehyde was converted into 2,3-dibromo-3-phenyl-1-(thiophen-2-yl)propan-1-one, which on treatment with various thiosemicarbazides in the presence of triethylamine in absolute ethanol, yielded the corresponding hydroxy pyrazolines 3a–h. All the compounds were characterized by IR, ¹H NMR, and ¹³C NMR spectra.     

Fragmentation of trimethylsilyl derivatives of 2-alkoxyphenols: A further violation of the ‘even-electron rule’

The mass spectra of trimethylsilyl (TMS) ethers of 2-methoxyphenols show abundant [M–30]⁺˙ ions originating from consecutive loss of two methyl radicals. This is illustrated by comparison of the accurate mass-measured and linked-scan spectra of the TMS derivatives of 2-methoxyphenol (guaiacol), 4-hydroxy-3-methoxybenzaldehyde (vanillin) and 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid methyl ester (ferulic acid methyl ester) with those of the TMS derivatives of phenol, 4-hydroxybenzaldehyde, 3-(4-hydroxyphenyl)-2-propenoic acid methyl ester (p-coumaric acid methyl ester), 3-methoxyphenol and 4-methoxyphenol. This distinctive ortho effect is valuable in the identification of isomeric phenolic compounds. In the spectra of the TMS derivatives of 2-ethoxyphenol and 2-propoxyphenol the sequential loss of two radicals is less pronounced, because elimination of the side-chain and a methyl group with rearrangement and hydrogen migration is competitive.     

Methods for the synthesis of 2-aminothiophenes and their reactions (review)

2-Aminothiophenes are readily formed as a result of various cyclization reactions. The method of preparation of derivatives of 2-aminothiophene-3-carboxylic acids and 2-amino-3-acylthiophenes from carbonyl compounds, nitriles that have an active methylene group, and sulfur is particularly simple and rich in possibilities. The aminothiophenes can be converted to other thiophene derivatives and used primarily for the preparation of condensed thiophenes such as thionaphthenes, thienopyrroles, thienothiazoles, thienoisothiazoles, thienopyrimidines, thienopyridines, and thienodiazepines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1299–1315, October, 1976.     

Synthesis and some transformations of benzo[b]thiophene derivatives

A number of 3-chloro-2-chlorocarbonylbenzo [b] thiophenes with alkyl substituants in various positions of the benzene ring were synthesized by arylation of acrylic acid with the corresponding alkyl-substituted iodobenzenes under the influence of catalytic amounts of palladium acetate and subsequent oxidation of the resulting arylacrylic acids with thionyl chloride. Replacement of the pyridine added in the oxidation reaction by triethylbenzylammonium chloride led to substantial increases in the yields of the desired products. The possibility of conversion of the resulting benzo [b] thiophene derivatives to thiophene ring-unsubstituted benzo[b] thiophenes was shown in the case of 3-chloro-2-chlorocarbonylbenzo [b] thiophene as a result of successive saponification of the 2-chlorocarbonyl group, decarboxylation, and dechlorination.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1618–1622, December, 1982.     

焦化汽油中硫化物类型分布的气相色谱-硫化学发光检测方法

建立了焦化汽油中硫化物类型分布的气相色谱-硫化学发光检测分析方法。考察了色谱条件对焦化汽油中各种硫化物分离的影响,定性了某焦化汽油中的74个硫化物。以硫化氢、乙硫醇、正丙硫醇、噻吩、2-甲基噻吩、2-乙基噻吩、2-丙基噻吩、碳四噻吩(tR=40.28 min)、苯并噻吩、甲基苯并噻吩(tR=58.13 min)的保留时间为尺度,计算了焦化汽油中各种硫化物的保留指数,并可推广到其他类型的汽油馏分中各种硫化物保留指数的计算,为仅能提供硫化物信息的仪器提供了可靠的定性依据。焦化汽油中几种主要硫化物(异丙硫醇、正丙硫醇、正丁硫醇、2-甲基噻吩、3-甲基噻吩、2,4-二甲基噻吩、2,3,4-三甲基噻吩)含量测定值的相对标准偏差均小于5%。当信噪比为3时,测得硫的检测限为0.05 mg/L。研究发现:同其他类型的汽油相比,焦化汽油的硫含量较高且所含硫醇比例明显偏高,2-甲基噻吩和3-甲基噻吩的含量差别较大。该法可为加氢脱硫催化剂和工艺的研究提供数据。     

Mass spectral studies on steroidal compounds—V: Rings B and A seco 5-keto compounds in the cholestane series

The mass spectra of several structurally related ring B seco 5-keto compounds (I to VII) have been examined. The mass spectra of I, II, III and IV are conspicuous by an intense peak at m/e112(C₇H₁₂O) and those of V (highest mass peak at [M ? CH₃COOH]), VI and VII by a prominent peak at m/e 100 (C₇H₁₀O), which apparently results from McLafferty rearrangement involving 5-keto function and an appropriate γ-hydrogen at C-8 and C-11. This rearrangement, leading to the aforementioned ions, is of diagnostic value in the characterisation of such compounds. The mass spectrum of VIII exhibits a prominent ion peak at m/e 332 (C₂₃H₄₀O) resulting from McLafferty rearrangement involving the 5-keto function and C2? H. This offers an excellent means of differentiating between the isomeric acids (III and VIII). The fragmentation pathways suggested are supported by accurate mass measurement of the salient fragment ions and in some cases by appropriate metastable peaks.     

Synthesis and Transformations of 3-Ethoxycarbonyl-2-(N-R-thioureido)thiophenes

3-Ethoxycarbonyl-2-(N-R-thioureido)-4,5,6,7-tetrahydrobenzo[b]thiophenes were obtained by the reaction of 2-amino-3-ethoxycarbonyl-4,5,6,7-tetrahydrobenzo[b]thiophene with isothiocyanates and of 3-ethoxycarbonyl-2-isothiocyanato-4,5,6,7-tetrahydrobenzo[b]thiophene with primary and secondary amines. The cyclization paths of the products leading to derivatives of thieno[2,3-d]pyrimidine and thieno[2,3-d]-1,3-thiazine were studied. The corresponding S-substituted derivatives were obtained by the alkylation of 3-R-2-thioxo-3,4,5,6,7,8-hexahydrobenzo[b]thieno[2,3-d]pyrimidin-4-ones.     

Selective multiple magnesiations of the thieno[3,2-b]thiophene scaffold

A full functionalization of all four positions of the thieno[3,2‐b]thiophene scaffold was achieved. Starting from 2,5‐dichlorothieno[3,2‐b]thiophene, magnesiation of the 3‐ and 6‐position using tmpMgCl?LiCl furnishes, after trapping with various electrophiles, 3,6‐difunctionalized dichlorothieno[3,2‐b]thiophenes. Subsequent dechlorination and regioselective metalation or regioselective magnesium insertion into the C? Cl bond provides fully functionalized thieno[3,2‐b]thiophenes. Furthermore, new condensed heterocycles and small oligomers of these compounds with potential applications in material chemistry have been prepared.