6289-46-9Relevant articles and documents
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.
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.
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.
