- Enantioselective Synthesis of L- and D-Isoserine via Asymmetric Hydrogenation of Methyl N-Phthaloyl-3-amino-2-oxopropanoate
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L- and D-isoserine were synthesized enantioselectively via asymmetric hydrogenation of 3-amino-2-oxoester 5 catalyzed by Cl.Recrystallization and deprotection of (S)-6 (81percent ee) afforded enantiomerically pure L-isoserine.The enantioface selection by the catalyst was opposite to that observed in asymmetric hydrogenation of other 2-oxoesters, such as methyl phenylglyoxylate and methyl 2-oxocyclohexylacetate.
- Nozaki, Kyoko,Sato, Naomasa,Takaya, Hidemasa
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- Novel method for synthesizing N-substituted phthalic anhydride-(S)-isoserine
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The invention provides a low-cost method for synthesizing N-substituted phthalic anhydride-(S)-isoserine. The method comprises the following two steps: (1) taking (R)-(-)-3-chloro-1,2-propanediol as astarting raw material to carry out a Gabriel reaction with phthalimide to generate an intermediate (S)-2-(2,3-dyhydroxy-propyl)-isoindole-1,3-dione; and (2) oxidizing the primary alcohol groups in the intermediate (S)-2-(2,3-dyhydroxy-propyl)-isoindole-1,3-dione to carboxyl groups by using a water solution of sodium hypochlorite under the catalyst of a nitrogen oxide of tetramethylpiperidine toprepare the N-substituted phthalic anhydride-(S)-isoserine. Through the method, the use of an expensive raw material (S)-isoserine is avoided, the raw materials are cheap and easily available, the cost is low, the product purity is high, the impurity content is low, and the method is a novel process which can realize industrial production.
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Paragraph 0055; 0057; 0060; 0063; 0066; 0069; 0072; 0075
(2018/10/11)
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- Method for synthesizing N-substituted phthalic anhydride (S)-isoserine
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The invention relates to a method for synthesizing N-substituted phthalic anhydride-(S)-isoserine. The method comprises the step that backflow water diversion reaction is carried out on (S)-isoserineand phthalic anhydride in a mixed solvent of petroleum ether/ normal hexane/ normal heptane and DMF. The method for synthesizing the N-substituted phthalic anhydride-(S)-isoserine has the advantages that the mixed solvent is selected to substitute a mixed solvent of methylbenzene and DMF in the prior art, the reaction temperature is lower, the occurrence of the side reaction is avoided, the purityof the obtained product is higher, the yield is higher, the used solvent can be reused, the aftertreatment operation is simple, the cost is reduced, the energy consumption is reduced, the environmental pollution is small, and the industrialized production is easy.
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Paragraph 0040; 0041; 0043; 0045; 0047; 0049; 0051; 0053
(2018/10/19)
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