- Method for preparing MGH by reacting sodium aldehydesulfite with MGH esterification liquid
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The invention relates to a method for preparing MGH by reacting sodium aldehydesulfite with MGH esterification liquid. MGH is glyoxylic acid L-menthol ester, and the method comprises the following steps: (1) reacting an MGH esterification liquid with sodium acetaldehyde sulfite to obtain an MGH sodium salt solution; (2) reacting the MGH salt solution with acetaldehyde to obtain a mixed system containing an MGH crude product; and (3) separating and purifying the MGH crude product to obtain an MGH fine product and an acetaldehyde sodium sulfite recovery solution. The method is simple in production process, simple and convenient to operate and mild in reaction condition, obviously reduces the generation of wastewater and waste salt, and greatly reduces the investment of distillation wastewater equipment and the cost of solid waste treatment.
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Paragraph 0110; 0111
(2021/02/10)
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- Modular Synthesis of Chiral NHC Precursors and Their Silver and Gold Complexes
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The stereoselective synthesis of chiral heterocyclic carbene precursors and the structural features of their silver and gold complexes were investigated. The prepared compounds are all based on the imidazolidine scaffold and bear the bulky tert-butyl subs
- Szabo, Zita,Timari, Matyas,Kassai, Rudolf,Szokol, Bianka,Benyei, Attila C.,Gáti, Tamás,Paczal, Attila,Kotschy, Andras
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p. 3572 - 3589
(2020/10/09)
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- Synthetic method for lamivudine
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The invention provides a synthetic method for lamivudine. The synthetic method comprises the following steps: cheap easily-available dihaloacetic acid is used as a raw material, the dihaloacetic acidand L-menthol are subjected to condensation, hydrolysis is performed to obtain menthyl glyoxylate, the menthyl glyoxylate and 2,5-dihydroxy-1,4-dithiane are subjected to condensation, halogenation isperformed, the halogenated product and silanized cytosine are subjected to coupling, reduction is performed, the reduced product and salicylic acid are subjected to salt formation to obtain the a salicylate, and finally recrystallization is performed to obtain the optically-pure lamivudine. According to the method provided by the invention, the raw materials used in the whole synthetic process arecheap and easy to obtain, the synthetic process is simple, the synthetic conditions are mild, so that the synthetic costs of the lamivudine are greatly reduced; the raw material utilization rate andreaction selectivity are high, so that the yield of the obtained lamivudine is higher; and at the same time, a chiral substrate is easily removed during the synthesis, three waste (waste water, wastegas and solid waste) generated in the method are less, and the method is suitable for industrialized large-scale production of the lamivudine.
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Paragraph 0028; 0031; 0038
(2019/11/21)
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- Emtricitabine synthesis method
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The invention provides an emtricitabine synthesis method, which comprises: carrying out condensation on cheap and easily available dihaloacetic acid as a raw material and L-menthol, hydrolyzing to obtain menthyl glyoxylate hydrate, condensing with 2,5-dihydroxy-1,4-dithiane, carrying out halogenation, coupling with silylated 5-flucytosine, reducing, carrying out salt forming with salicylic acid toobtain emtricitabine salicylate, and finally re-crystallizing to obtain optically pure emtricitabine. According to the present invention, the whole synthesis process has characteristics of inexpensive and easily available raw materials, simple synthesis process and mild synthesis conditions, such that the synthesis cost of emtricitabine is substantially reduced; various raw materials have characteristics of good reaction selectivity and high utilization rate, such that the yield of the obtained emtricitabine is high; and the chiral substrate is easily removed during the synthesis, and the generated three-waste pollutants are less, such that the method is suitable for industrial large-scale production of emtricitabine.
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Paragraph 0028; 0031; 0038
(2019/11/29)
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- A reduction Suitqable to intermediate MGH synthesis process impurities
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The invention discloses a method of reducing impurities in a synthesis process of an emtricitabine intermediate MGH. The method comprises the following steps: taking L-menthol and glyoxylic acid as raw materials; carrying out an esterification reaction under acid catalysis; carrying out an addition reaction under the action of sodium hydrogen sulfite; carrying out a hydroxylation reaction under the action of formaldehyde; carrying out post-treatment to obtain L-menthyl dyhydroxy acetate, wherein in the process of the addition reaction, the pH value is 4-6, and the reaction temperature is 40-80 DEG C and the reaction time is 4-10 hours. With the adoption of the method, the reaction time is greatly shortened and a reaction period is shortened; meanwhile, in a reaction process, cyclohexane is only used as an organic solvent, so that the operation is simple and the post-treatment is convenient; by controlling process conditions and post-treatment conditions, the content of impurities is greatly reduced and the yield is improved. Meanwhile, certain helps are provided for registration and application, and production and center control of emtricitabine, and improvement of quality standards of the emtricitabine intermediate.
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Paragraph 0014-0017; 0038-0043
(2017/08/25)
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- Method for continuous production of L-menthol-dihydroxy acetate
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The invention provides a method for continuous production of L-menthol-dihydroxy acetate. The method comprises the steps: (1) subjecting menthol to a reaction with glyoxylic acid in an inert solvent in the presence of a catalyst, so as to obtain an esterification solution; (2) mixing the esterification solution with sodium bisulfite, and carrying out an addition reaction, so as to obtain an addition reaction solution; and (3) mixing the addition reaction solution with formaldehyde, and carrying out a reduction reaction, thereby preparing a compound represented by a formula MGH. According to the method provided by the invention, continuous production can be achieved, side reactions are effectively controlled, the reaction selectivity and raw material utilization ratio are increased, the treatment capacity of wastewater is reduced, and the unit-volume productivity of equipment is improved, so that the method is applicable to industrial large-scale production.
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Paragraph 0066-0069
(2018/03/01)
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- A PROCESS FOR STEREOSELECTIVE SYNTHESIS OF 5-FLUORO-1-(2R,5S)-[2-(HYDROXYMETHYL)-1,3-OXATHIOLAN-5-YL]CYTOSINE
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The present invention provides an improved process for stereoselective preparation of 5-fluoro-l-(2R,5S)-[2-(hydroxymethyl)-l,3-oxathiolan-5-yl]cytosine and pharmaceutically acceptable salts thereof.
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Page/Page column 9
(2011/10/03)
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- An efficient method for preparation of chiral arylmenthol glyoxylates
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Glyoxylates of three chiral alcohols were conveniently prepared by reaction of the alcohol with oxalyl chloride followed by reduction of the resulting alkoxy oxalyl chloride with tributyl- tin hydride. The products were isolated in 75-80% yield by straightforward flash chromatography.
- Blanco, Jose M.,Caamano, Olga,Fernandez, Franco,Garcia-Mera, Xerardo,Lopez, Carmen,Rodriguez-Borges, Jose E.,Hergueta, Antonio R.
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p. 1590 - 1592
(2007/10/03)
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