6289-46-9Relevant academic research and scientific papers
117. Preparation, Structure, and Properties of All Possible Cyclic Dimers (Diolides) of 3-Hydroxybutanoic Acid
Seebach, Dieter,Hoffmann, Torsten,Kuehnle, Florian N. M.,Kinkel, Joachim N.,Schulte, Michael
, p. 1525 - 1540 (1995)
In connection with the proposed structure of a trans-membrane cellular ion channel consisting of a complex poly (P(3-HB)) and calcium phosphate, CaPPi (ca. 150 units each), which is supposed to contain s-cis-bonds or even more highly strained ester conformations, we have prepared and studied the properties of the cyclic dimer of 3-HB, the diolide 1.All possible forms of 1, the rac-, the meso-, and the enentiomerically pure (R,R)- and (S,S)-compounds were prepared, purified, and characterized.The synthesis (Scheme 1) started from dimethyl succinate with the key step being the Baeyer-Villiger oxidation of the rac- and meso-2,5-dimethylcyclohexane-1,4-diones 5.The rac-diolide 1 was resolved by preparative chromatography on a Chiralcel OD column (Fig. 1).The crystal structures of rac-1 (Fig. 3) and of meso-1 (Fig. 5) were determined by X-ray diffraction: the diolides 1 contain s-cis-ester bonds and an ester group with a conformation half way to the transition state of rotation (Fig. 2).Strain energies for the diolides 1 up to 17.8 kcal/mol are suggested.Accordingly, these compounds show reactivities similar to those of carboxylic-acid anhydrides or even acid chlorides.They cannot be chromatographed on silica gel, and they react with primary, secondary, and tertiary alcohols, and with amines to form derivatives of open chain 3-HB 'dimers', hydroxy acids 6, esters 7, and amines 8 (Scheme 2).The rate of acid-catalyzed ring opening of the diolides 1 with alcohol has been measured (Figs. 6 and 7).From the results described, we conclude that it is unlikely for strained and reactive ester conformations to occur as a part of ion channels through phospholipid bilayers of cells.
Preparation method of dimethyl succinyl succinate
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Paragraph 0025-0054, (2021/02/24)
The invention provides a preparation method of dimethyl succinyl succinate, which comprises the following steps: S10, adding a methanol solution of dimethyl succinate into a reactor, heating to 60+/-1DEG C, and keeping the temperature for 15-30 minutes to obtain a first mixed solution, S20, dropwise adding a methanol solution of 1, 8-diazacyclo[5, 4, 0]undecen-7 (DBU) into the first mixed solution, and obtaining a second mixed solution after dropwise adding is finished, S30, heating the second mixed solution to 80-140 DEG C, and carrying out a reaction for 2-3 h to complete the reaction so asto obtain a third mixed solution, and S40, cooling the third mixed solution to 80 DEG C, distilling, and cooling to room temperature to obtain a dimethyl succinyl succinate solid. According to the preparation method of dimethyl succinyl succinate, DBU is adopted as a catalyst, dimethyl succinate and methanol are directly reacted to synthesize dimethyl succinyl succinate, the preparation process is simple, the yield of the synthesized product is greater than 94%, and the synthesis efficiency is greatly improved.
Environment-friendly production method for greatly reducing sewage discharge of dimethyl succinylsuccinate
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Paragraph 0018-0019; 0021-0024; 0026-0028, (2021/04/03)
The invention provides an environment-friendly production method for greatly reducing sewage discharge of dimethyl succinylsuccinate. According to the technical scheme, succinic acid and methyl alcohol react under the nitrogen protection condition to generate dimethyl succinate, the dimethyl succinate serves as a reaction solvent, sodium methoxide is dropwise added into the reaction solvent underthe ultrasonic oscillation condition, after dropwise adding is completed, a reflux reaction continues to be conducted for a period of time, and the reaction sufficiency can be improved through microcosmic vibration of fluid; after the reaction is finished, stirring, slurrying and suction filtration are performed, washing with absolute methanol is performed, and fractionation is performed so as torecover methanol and dimethyl succinate; the filter cake is neutralized with dilute sulfuric acid, and reduced pressure distillation is performed to obtain a final product. On the basis, a pickling solution is prepared from a residual solution obtained by reduced pressure distillation, and calcium chloride is added into the excessive pickling solution, so that a calcium sulfate byproduct can be obtained; meanwhile, the high-temperature residual liquid after fractionation is used for heating the dimethyl succinate in the next stage, so that the waste heat is effectively utilized, and the sewagedischarge amount is reduced.
Synthetic method of dimethyl succinyl succinate
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Paragraph 0021-0050, (2020/12/30)
The invention relates to the technical field of organic synthesis, and particularly discloses a synthetic method of dimethyl succinyl succinate. The synthesis method comprises the following steps: taking liquid paraffin as a reaction solvent and dimethyl succinate as a raw material to react with sodium methoxide, and performing acidification treatment, suction filtration, washing and drying to obtain the dimethyl succinyl succinate. According to the synthetic method of dimethyl succinyl succinate, liquid paraffin is adopted to replace dimethyl succinate to serve as a reaction solvent, the problems that excessive dimethyl succinate is prone to side reaction and prone to hydrolysis in the high-temperature polymerization and acidification process to cause loss of raw materials are effectivelysolved. Besides, the yield and purity of the dimethyl succinyl succinate product are guaranteed, the average yield of the product is 85.54%, the purity of the product is 99.5% or above, and the product quality is stable.
Preparation method of high-purity dimethyl succinyl succinate
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Paragraph 0018; 0021-0024; 0026-0028, (2019/06/30)
The invention provides a preparation method of high-purity dimethyl succinyl succinate.According to the technical scheme, a novel design is carried out on the synthesis condition of dimethyl succinylsuccinate; specifically, the preparation method of thehigh-purity dimethyl succinyl succinate comprises the following steps of: firstly, reacting succinic acid and methanol under the condition of nitrogen protection to generate dimethyl succinate, taking the dimethyl succinate as a reaction solvent, dropwise adding sodium methoxide into the dimethyl succinate under the condition of ultrasonic oscillation, continuously carrying out reflux reaction for a period of time after the dropwise addition is finished, and improving the adequacy of the reaction by micro-vibration of a fluid;stirring and pulping are carried outafter the reaction is finished, suction filtration is carried out, anhydrous methanol is used for washing, and fractional distillation is carried out, so that the methanol and the dimethyl succinate are recovered;afilter cake is subjected to reduced pressure distillation after being neutralized by dilute sulfuric acid to obtain a final product.The preparation method of thehigh-purity dimethyl succinyl succinate can effectively ensure the yield of the product, simplify the process steps to a certain extent, and simultaneously obtain the product with higher purity.The preparation method of thehigh-purity dimethyl succinyl succinate achieves good technical effect by innovative technical improvement and has great popularization prospect.
HIGH-AND LOW-POTENTIAL, WATER-SOLUBLE, ROBUST QUINONES
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Paragraph 00124, (2018/09/21)
Substituted hydroquinones, 1,4-quinones, catechols, 1,2-quinones, anthraquinones, and anthrahydroquinones are disclosed herein. The substituted hydroquinones and catechols have the formula: while the substituted 1,4-quinones or 1,2-have the corresponding oxidized structure (1,4- benzoquinones and 1,2-benzoquinones). One or more of R1, R2, R3 and R4 include a sulfonate moiety, a sulfonimide moiety, or a phosphonate moiety, and any of R1, R2, R3 and R4 that do not include one of these moieties include an alkyl, a cycloalkyl, a thioether, a sulfoxide, a sulfone, a haloalkyl, a halogen, a nitrile, an imide, a pyrazole, or combinations thereof. The substituted anthraquinones have the formula: while the substituted anthrahydroquinones have the corresponding reduced structure. One or more of R1-R8 have a sulfonate or phosphate tethered to the ring by a thi other, amine, or ether including one or more alkyl groups. Any of R1-R8 that do not contain one of these moieties include an alkyl, a cycloalkyl, a thiother, a sulfoxide, a sulfone, a haloalkyl, a halogen, a hydroxyl, an alkoxyl, an ether, an amine, or hydrogen The substituted hydroquinones, 1,4-quinones, catechols, 1,2-quinones, anthraquinones, or anthrahydroquinones are soluble in water, stable in aqueous acid solutions, and have useful reduction potentials in the oxidized form. Accordingly, they can be used as redox mediators in emerging technologies, such as in mediated fuel cells or organic-mediator flow batteries.
Method for continuous production of dimethyl succinylo succinate
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Paragraph 0022; 0031; 0036, (2017/08/31)
The invention provides a method for continuous production of dimethyl succinylo succinate. The technical scheme employs continuous drip adding to carry out Claisen condensation reaction on dimethyl succinate and sodium methoxide and Dieckmann condensation reaction, and can realize continuous discharge, after a certain product is collected, and then dilute sulfuric acid acidification is carried out to obtain dimethyl succinylo succinate. The method provided by the invention is designed based on classical experimental principles, and the operation mode is improved to form a brand-new technological process. The technical scheme shortens the reaction time, also reduces energy consumption, significantly improves the production efficiency, and at the same time overcomes the problem of large quality difference between different batches in batch production. The method provided by the invention takes innovative technological improvement and achieves good technical effect, simultaneously has the characteristics of low cost and easy realization, thus having good popularization prospect.
Alkylation of methyl 4-chloro-3-oxobutanoate with di- and tribromoalkanes
Ismailov,Ibragimova,Sadykhova,Mamedov,Nagiev,Yusubov
, p. 1099 - 1101 (2017/09/07)
Alkylation of methyl 4-chloro-3-oxobutanoate with 1,2-dibromoethane, 1,3-dibromopropane, and 1,2,3-tribromopropane afforded the corresponding dimethyl 2,5-dioxocyclohexane-1,4-dicarboxylate enol ethers.
Preparation method for quinacridone and derivatives of quinacridone
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Paragraph 0027; 0031; 0035, (2017/08/29)
The invention relates to the field of synthesis of organic pigments and discloses a preparation method for quinacridone and derivatives of the quinacridone. The preparation method comprises the steps that dimethyl succinate generates sodium dimethyl succinylsuccinate (DMSS) through cyclic condensation under an effect of sodium methoxide, and then being acidized into DMSS; condensation reaction occurs between the DMSS and aniline or substituted aniline, an intermediate product generated during condensation is directly oxidized and dehydrogenated by sodium 3-nitrobenzene sulfonate to obtain an oxidative product; and finally coarse products of the quinacridone or the derivatives of the quinacridone are prepared from the oxidative product in a ring-closing mode under an effect of polyphosphoric acid, and finally finished products of the quinacridone or the derivatives of the quinacridone are obtained through pigmentation treatment.
A process for preparing 1,4-cyclohexane dicarboxylic acid diester method
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Paragraph 0021, (2017/01/12)
A new method for preparing 1,4-cyclohexane dioctyl phthalate diester. The method comprises: using a succinate diester as a material, obtaining succinyl succinate diester by means of ester condensation, and hydrogenating and dehydrating the succinyl succinate diester to obtain 1,4-cyclohexane dioctyl phthalate diester. The present invention provides a new way for preparing 1,4-cyclohexane dioctyl phthalate diester, and has a very important development potential and a broad application perspective.
