- A L - dibenzoyl tartaric acid for the preparation of dimethyl
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The invention belongs to the technical field of chemical synthesis method, in particular to a L - dibenzoyl tartaric acid for the preparation of dimethyl, the L - dibenzoyl tartaric acid for the preparation of dimethyl, comprises the following steps: S1, to L - tartaric acid, benzoyl chloride, thionyl chloride as the raw material, Lewis acid as catalyst, toluene as the solvent, through esterification, Anhydrized reaction, purification L - dibenzoyl tartaric acid [...]; S2, will be L - dibenzoyl tartaric acid [...] in pure water in the hydrolysis to obtain L - dibenzoyl tartaric acid hydrate wet product; S3, L - dibenzoyl tartaric acid hydrate the wet product in methanol and catalyst under the action of the esterification reaction, purify to get the L - dibenzoyl tartaric acid dimethyl ester. The invention the raw materials used are cheap and easy to obtain, mild reaction conditions, to recycle the methanol can be used repeatedly, after treatment is convenient, and is suitable for industrial production, it is worth.
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Paragraph 0024; 0030-0033; 0034; 0040-0043; 0050-0053
(2019/03/23)
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- A compound, catalyst component and its catalyst
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The invention discloses a compound with a novel structure. The structure of the compound is represented by formula I. In the formula I, R1, R2, R3 and R4 can be same to each other or different from each other, and are respectively independently selected f
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Paragraph 0057-0059
(2017/10/06)
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- Reduction of diesters of 1,2-diols. Regioselective C-O bond cleavage of the anionic forms
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The electrochemical reduction of benzoate diesters of glycols has been studied in acetonitrile and N,N-dimethylformamide as solvents. The reductions occur in two closely spaced one-electron steps, and it was found that the dianion diradicals decompose by one of two routes, depending on the substituents on the ethylene moiety: cleavage of two benzoates to produce alkene or formation of benzil by way of a postulated cyclic intermediate to produce also the dianion of the diol. These correspond to cleavage of the R-OC(O)Ar bonds and the RO-C(O)Ar bonds, respectively. When the radical formed by the former cleavage is a primary or secondary radical, the reaction is too slow to compete with the latter reaction that produces benzil. However, when that radical is either tertiary or benzylic, the former cleavage reaction is fast and no benzil is detected. The dianions of p-cyano- and p-nitrobenzoate esters are rather stable on the voltammetric time scale. However, the addition of lithium ions results in detectable formation of 4,4′-dicyanobenzil from four different p-cyanobenzoate diesters.
- Macias-Ruvalcaba, Norma A.,Moy, Cheryl L.,Zheng, Zi-Rong,Evans, Dennis H.
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p. 4829 - 4834
(2007/10/03)
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- Factors affecting conformation of (R,R)-tartaric acid ester, amide and nitrile derivatives. X-Ray diffraction, circular dichroism, nuclear magnetic resonance and ab initio studies
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Derivatives 2a-15a of(R,R)-tartaric acid (la) with all combinations of methyl ester. amide. N-methylamide and N,N-dimethylamide groups, as well as the corresponding O,O-dibenzoyl derivatives 1b-15b and nitriles 16-18 have been synthesized. Their conformations have been studied by the NMR and CD methods in solution as well as by X-ray diffraction in the crystalline state. The preference for planar. T conformation of the four carbon chain is observed under conditions restricting the α-hydroxyacid, ester or amide group to be nearly planar. This conformation being stabilized by intramolecular hydrogen bonds of the S(5) motif and the electrostatic CO/C(β)H and CN/C(β)H coplanar bond interactions. The C=O/C(α)-O bond system tends to be either synplanar tester, acid), or antiplanar tester, primary and secondary amide). Ab initio calculations allowed to demonstrate that for the isolated molecules of diamides 10a and 15a there is strong preference for gauche C+(a,a) conformers, the driving force being the formation of the hydrogen bonded six-membered cycles of tire S(G) motif joining the OH and C=O groups from two different halves of the molecule. The results compare favourably with the experimental values derived from NMR spectra of 15a in nonpolar solvent. In the absence of intramolecular hydrogen bonding the N,N-dimethylamide group is better accommodated in a gauche G- conformer. This releases the nonbonded interaction due to the amide methyl group anti to the carbonyl group.
- Gawronski, Jacek,Gawronska, Krystyna,Skowronek, Pawel,Rychlewska, Urszula,Warzajtis, Beata,Rychlewski, Jacek,Hoffmann, Marcin,Szarecka, Agnieszka
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p. 6113 - 6144
(2007/10/03)
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