36983-12-7Relevant academic research and scientific papers
Method for preparing D-p-methylsulfonylphenylserine ethyl ester with high stereoselectivity
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Paragraph 0013; 0015; 0034-0060, (2021/03/13)
The invention discloses a method for preparing D-p-methylsulfonylphenyl serine ethyl ester with high stereoselectivity, which has the advantages of mild reaction conditions, high stereoselectivity andlow corrosivity to production equipment, and belongs to the field of organic reaction catalyzed by small molecules. According to the preparation method provided by the invention, p-methylsulfonylbenzaldehyde and N-Boc glycine ethyl ester are used as basic raw materials, and trifluoromethanesulfonic acid di-n-butyl boron ester is used as an additive, so that optically pure D-type p-methylsulfonylphenylserine ethyl ester is obtained with high stereoselectivity under the condition that Lproline is used as a catalyst. Compared with the existing chemical synthesis method, the method disclosed by the invention has the advantages that the highest total yield of the D-methylsulfonylphenyl serine ethyl ester can reach 75%, and the ee value of the obtained product reaches 73%. The method is low incost and has better yield and optical purity.
Synthesis method of D-p-methylsulfonylphenyl serine ethyl ester
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Paragraph 0008-0009, (2020/01/25)
The invention discloses a synthesis method of D-p-methylsulfonyl phenyl serine ethyl ester. The method comprises the following steps: preparing p-methylsulfonylphenylserine copper by taking p-methylsulfonylbenzaldehyde, copper sulfate and glycine as main raw materials; then adding anhydrous ethanol and concentrated sulfuric acid into an esterification reaction kettle, carrying out heating for a reaction, filtering out copper sulfate while the solution is hot, carrying out cooling for crystallizing, and carrying out filtering to obtain DL p-methylsulfonylphenyl serine ethyl ester sulfate, dissolving the DL p-methylsulfonylphenyl serine ethyl ester sulfate into water, removing copper ions by using a saturated sodium sulfide solution, adding an alkali into the mother solution for dissociationto obtain DL p-methylsulfonylphenyl serine ethyl ester, and adding a resolving agent for resolving to obtain a product. The method is simple in process, high in yield, low in cost and small in environmental pollution and is suitable for enterprise production.
DL-p-methylsulfonylphenyl serine ethyl ester preparation method
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Paragraph 0020-0038, (2020/02/29)
The invention discloses a DL-p-methylsulfonylphenyl serine ethyl ester preparation method, which comprises: 1) adding glycine ethyl ester hydrochloride into ethanol, and carrying out heating reflux; 2) dissolving basic cupric carbonate in ammonia water, and adding into the solution obtained in the step 1); 3) adding KOH into the solution obtained in the step 2) to adjust the pH value of the solution, and adding p-methylsulphonyl benzaldehyde, carrying out a reaction; and 4) after the reaction is finished, recovering ethanol in the reacted substance, adding ammonia water into the residue, regulating the pH value, cooling the solution, filtering, washing with ice water, and drying to obtain the p-methylsulfonylphenyl serine ethyl ester. According to the invention, the target product is generated by carrying out a one-step reaction on glycine ethyl ester hydrochloride and p-methylsulphonyl benzaldehyde under the catalysis of basic cupric carbonate and an alkali, wherein the reaction process does not require the use of concentrated sulfuric acid so as to completely avoid the generation of strong acid wastewater, protect and the environment, avoid the possible danger in the sulfuric acid transportation and production process, achieve the safety and easily improve the operation efficiency.
P-Methyl sulfone phenyl ethyl serinate and synthetic method thereof
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Paragraph 0017; 0040; 0045-0059, (2018/09/12)
The invention discloses a synthetic method of P-methyl sulfone phenyl ethyl serinate, comprising the steps of S1, adding ethyl glycinate hydrochloride into methanol, and heating to dissolve to form afirst solution; S2, adding copper sulfate pentahydrate in the first solution to form a second solution by dissolving; S3, adjusting PH value of the second solution to meet the condition for alkaline reaction, adding P-methylsufonyl benzaldehyde to allow reaction, and holding the temperature and controlling the PH value to keep reaction condition values during reaction; S4, recycling methanol in the reacted materials, adding water to the residue to form a third solution, cooling, and centrifugally separating to obtain P-methyl sulfone phenyl ethyl serinate. The ethyl glycinate hydrochloride andP-methylsufonyl benzaldehyde are subjected to further reaction under the catalytic action of copper sulfate and an organic base to generate a target product; no sulfuric acid is used in the reactionprocess, the amount of waste acid in waste water is decreased, and the environment is protected; dangers that may occur during sulfuric acid transport and production are avoided, better safety is provided, and operating efficiency can be improved.
Chiral resolution of racemic p-methylsulfonylphenyl serine ethyl ester with lipases: The mechanism of side reaction and its suppression
Guo, Rui,Fan, Yong-Xian,Chen, Xiao-Long,Shen, Yin-Chu
, p. 157 - 166 (2013/03/29)
The d-threo form of p-methylsulfonylphenyl serine ethyl ester (MPSE) is a key intermediate for the synthesis of florfenicol. In this study, chiral resolution of dl-threo-p-MPSE with lipases was investigated. Among a series of lipases, Novzyme 435 was the best to resolve dl-threo-p-MPSE with the conversion rate of 36.83% and ee value of 35.13%. To improve the conversion rate and ee value, a number of byproducts were identified and characterized using reverse-phase HPLC, normal-phase HPLC, 1H NMR, and LC-MS when threo-p-MPSE was hydrolyzed by lipases in organic medium. Mechanisms of generating main byproducts are proposed, and a suppressing method is provided. The results showed that byproduct p-methylsulfonyl benzaldehyde serves as the key intermediate during the whole side reaction process. It was also observed that threo-p-MPSE with a proper hydrolytic velocity served as a driving force to generate p-methylsulfonyl benzaldehyde and accelerated the side reactions. Finally, a feasible approach to suppress side reactions in enzymatic catalysis is offered. The conversion rate and ee value were greatly improved by 69.29 and 46.26%, respectively, using Zn2+ compared to those without Zn 2+.
An efficient enantioselective synthesis of florfenicol based on sharpless asymmetric dihydroxylation
Wang, Zhong-Hua,Zheng, Chen,Li, Feng,Zhao, Lei,Chen, Fen-Er,He, Qiu-Qin
experimental part, p. 699 - 704 (2012/04/04)
An efficient and highly enantioselective synthesis of florfenicol- via a new intermediate threo-dihydroxy ester, with a Sharpless asymmetric dihydroxylation as the key step, is reported. A ring-opening/reduction strategy avoids the formation of a chlorinated byproduct that occurs in Schumachers phenyloxazoline procedure. The overall yield of florfenicol by this new process is 23% based on 4-(methylsulfonyl)benzaldehyde. Georg Thieme Verlag Stuttgart · New York.
