4282-31-9Relevant articles and documents
Preparation method of thiophene carboxyl-substituted derivative
-
Paragraph 0074; 0076; 0078, (2018/05/07)
The invention provides a preparation method of a thiophene carboxyl-substituted derivative. The preparation method comprises that glyoxal and a compound A undergo a cyclization reaction to produce a 2, 2'-thiophene diester compound, and the 2, 2'-thiophene diester compound undergoes a hydrolysis reaction to produce 2-thiophenecarboxylic acid or 2, 2'-thiophene dicarboxylic acid. The preparation method has simple processes. Compared with the existing complex production method used under harsh production conditions, the one-pot method can realize the synthesis of a desired product. Compared withthe existing multiple-step synthesis method, the one-pot method improves a yield by at least 50%. Through optimizing the production processes and the synthesis route, the method has few side reactions in production, is free of a selective reaction, produces less impurities, is easy to post-process, needs mild production conditions and is suitable for an industrial production mode .
METHOD FOR PRODUCING HETEROAROMATIC CARBOXYLIC ACID
-
Paragraph 0039; 0041; 0042, (2018/08/09)
PROBLEM TO BE SOLVED: To provide a method for producing heteroaromatic carboxylic acids at good yields, when producing the heteroaromatic carboxylic acids by the oxidation of methyl-substituted heteroaromatic compounds. SOLUTION: A method for producing a heteroaromatic carboxylic acid includes oxidizing a methyl-substituted heteroaromatic compound, having one or more methyl groups on a heteroaromatic ring, with a basic compound and a permanganate. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
Preparation method of refined thiophene-2,5-dicarboxylic acid
-
Paragraph 0020; 0021; 0022; 0023; 0024; 0025; 0026, (2017/12/30)
The invention provides a preparation method of refined thiophene-2,5-dicarboxylic acid. The preparation method specifically comprises the following steps: firstly taking 2,5-dichlorothiophene or 2,5-dibromothiophene as a raw material and reacting with magnesium chips in a solvent to prepare a corresponding format reagent solution; then introducing carbon dioxide gas or adding dry ice in batches, quenching a reaction system with water after the completion of reaction, extracting an organic solvent, drying by distillation to obtain a thiophene-2,5-dicarboxylic acid crude product; finally performing re-crystallization by adopting ethanol to obtain the refined thiophene-2,5-dicarboxylic acid. The invention can provide the preparation method of the refined thiophene-2,5-dicarboxylic acid, which is simple in process, short in step, low in production cost and high in product conversion rate.
Preparation method of 2,5-thiophenedicarboxylic acid
-
Paragraph 0022-0148, (2017/02/17)
The invention discloses a preparation method of 2,5-thiophenedicarboxylic acid, and solves the problem that the existing technique is low in yield and can pollute water. The method comprises the following steps: (1) adding adipic acid and thionyl chloride into a reaction kettle according to the weight ratio of 1:(5-12), adding a catalyst into the reaction kettle, stirring, heating to 75-95 DEG C, carrying out reaction, and treating at high temperature to obtain acyl chloride; (2) carrying out hydrolysis on the acyl chloride until the acyl chloride completely becomes a solid, supplementing water, regulating the pH value to 9-12, heating to 81-85 DEG C, and keeping the temperature for 2-2.5 hours; transferring the material into a decolorization kettle, regulating the pH value to 5-8, stirring for decolorization, and filtering to obtain a filtrate; (3) adding hydrochloric acid into the filtrate, stirring, and centrifuging to obtain a crude product; (4) heating the obtained crude product under reflux, and filtering to obtain a refined product; and (5) drying the refined product, pulverizing and packaging to obtain the product. The method is high in yield, shortens technical process time, and lowers the generation quantity of three wastes.
Is carbon dioxide able to activate halogen/lithium exchange?
Durka, Krzysztof,Lulinski, Sergiusz,Dabrowski, Marek,Serwatowski, Janusz
, p. 4562 - 4570 (2014/08/05)
The unexpected effect of carbon dioxide on halogen-lithium exchange (HLE) reactions of selected haloarenes with tBuLi was investigated. In an aliphatic hydrocarbon solvent (pentane), the HLE does not occur at ca. -70 C but, surprisingly, pouring the mixture of reactants onto dry ice and subsequent aqueous acidic hydrolysis gave carboxylic acids resulting from the quench of the first-formed aryllithiums with carbon dioxide. This suggests that CO 2 acts as a promoter of the HLE and, subsequently, serves as an electrophile to trap the aryllithium intermediates that are generated in situ. Theoretical DFT calculations were used to develop a plausible mechanism for the reaction, which indicates that CO2 is a much weaker donor than tetrahydrofuran (THF) so the cleavage of inert tBuLi cubic tetramers into more reactive solvated dimeric species (tBuLi)2(CO2) 4 is disfavored by 42.8 kJ per mol of (tBuLi)4. It is possible that this deaggregation process occurs to some extent when a large excess of CO2 is used. Copyright
A simple and facile carboxylation method and its application for synthesis of liquid crystals
Lee, Adam Shih-Yuan,Wu, Chih-Chiang,Lin, Li-Shin,Hsu, Hsiu-Fu
, p. 568 - 572 (2007/10/03)
Sonication of a mixture of magnesium powder, 1,2-dibromoethane, aryl bromide and diethyl dicarbonate in THF followed by treatment with BF 3·OEt2 at room temperature afforded aryl ester with reasonable yield. A series of aryl bromides were investigated and transformed to their corresponding aryl esters under the reaction conditions.
Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 16. Model studies for the construction of conjugated polymers
Aitken, R. Alan,Drysdale, Martin J.,Hill, Lawrence,Lumbard, Keith W.,Maccallum, James R.,Seth, Shirley
, p. 11039 - 11050 (2007/10/03)
Reaction of a range of bis(ylides) with acid chlorides has been used to prepare the bis(oxoylides) 11-15. Similarly a range of simple ylides react with bis(acid chlorides) to give bis(oxoylides) 19-27 with the isomeric structure. Flash vacuum pyrolysis (FVP) of one example of the first type results in extrusion of Ph3P rather than the expected Ph3PO while six examples of the second type do extrude Ph3PO upon FVP at 500 °C to afford the bis(alkynes) 28. Examples of the corresponding bis(tributylphosphonium ylides) have also been prepared but attempts to construct a tetrakis(oxoylide) 31 using a stepwise approach were unsuccessful. Fully assigned 13C NMR spectra are presented for six of the bis(oxoylides).
Stereoselective synthesis of thiophenedimethyl- and benzenedimethyl- α,α′-bridged bis(glycines)
Hammer, Kristin,Benneche, Tore,Hope, Hakon,Undheim, Kjell
, p. 392 - 402 (2007/10/03)
Conformationally constrained cystine analogues have been synthesized which have an all-carbon backbone-chain as a bridge between the α,α′-positions in two glycine units. An aromatic ring consisting of a 1,2-disubstituted benzene or a 2,3- and 2,5-disubstituted thiophene has been inserted into the bridge. Chiral auxiliaries were used to effect stereoselective syntheses of the (S,S)-bis(amino acids). The latter were further derivatized as Fmoc-derivatives suitable for peptide syntheses. The product 2,3-bis[(2A,5S)-(2,5-dihydro-3,6-dimethoxy-2-isopropyl-5-pyrazinyl)methyl]-5- methylthiophene has been subjected to X-ray analysis. Acta Chemica Scandinavica 1997.
A New Indirect Application of Aggregative Activation: Synthesis of Esters by Cobalt-Catalyzed Carbonylation of Aryl, Heterocyclic, and Vinyl Halides under Atmospheric Pressure
Marchal, Joel,Bodiguel, Jacques,Fort, Yves,Caubere, Paul
, p. 8336 - 8340 (2007/10/02)
Sun lamp illuminated alkoxycarbonylation of aryl, heteroaryl, and vinyl halides was performed under atmospheric pressure of CO in the presence of a cobalt catalyst in situ generated from Co(OAc)2.Illunination through a Pyrex flask was sufficient to catalyze the reaction.This process avoids the use of Co2(CO)8 and excess CH3I, which were required in the earlier procedure.A SRN1 mechanism is proposed.
Metal Alkoxide Modified Organometallic Reagents. Preparation and Stability of Organolithium Reagents in Tetrahydrofuran in the Presence of Magnesium 2-Ethoxyethoxide
Screttas, Constantinos G.,Steele, Barry R.
, p. 1013 - 1017 (2007/10/02)
The metalating ability of alkyllithium reagents and their tendency to cleave THF are greatly diminished in the presence of magnesium 2-ethoxyethoxide, 1.Advantage may be taken of this to generate organolithium reagents in THF in the presence of 1 under conditions not normally favorable to their stability.Thus, by reaction with metallic lithium in the presence of 1 in THF, the compounds RX (R = n-Bu, s-Bu, t-Bu, cyclohexyl, menthyl, p-methoxyphenyl, o-(methoxymethyl)phenyl; X = Cl, Br) have been converted to the corresponding organometallic reagents.In the absence of 1 the alkyllithium reagents formed react with the solvent, resulting in reduced yields and often alternative products.In the case of the preparation of the arylmetal reagents the presence of 1 suppresses either subsequent orthometalation (R = p-methoxyphenyl) or Wittig rearrangement (R = o-(methoxymethyl)phenyl) to give a clean replacement of halogen by the metal.The presence of THF is also tolerated in the preparation of these two arylmetal reagents by halogen-metal exchange using n-butyllithium in the presence of 1 whereas if 1 is absent little or none of the desired product is obtained.
