- Preparation method of chiral 4 - aryl - β β-amino acid derivative
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Provided is a method for preparing a chiral 4-aryl-β-amino acid derivative. The preparation method comprises hydrogenating an enamine compound having a structure as shown in Formula III in an organic solvent in the presence of a catalyst containing a transition metal and BIBOPs. The preparation method of the present invention uses a small amount of a selected asymmetric catalyst, and has a simple operation, mild reaction conditions, a high yield, a high stereoselectivity, and better industrial application and economic values.
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Paragraph 0029-0031
(2021/11/14)
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- Recycling method of sitagliptin key intermediate degradation waste
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The invention provides a recycling method of a sitagliptin key intermediate degradation waste, and belongs to the technical field of resource reutilization. The method provided by the invention comprises the following steps: preheating the sitagliptin key intermediate degradation waste at 40-80 DEG C to obtain a preheated material; in the presence of an alcohol organic solvent, carrying out alcoholysis reaction on the preheated material to obtain an alcoholysis material; mixing the alcoholysis material with an aminating agent and then carrying out ammonolysis reaction to obtain an ammonolysismaterial; and purifying the ammonolysis material to obtain a recovered product with a structure shown in a formula III. According to the method provided by the invention, waste resource reutilizationin a sitagliptin bulk drug production process is realized, economic loss caused by degradation of the key intermediate in the sitagliptin bulk drug production process is reduced, and the problem of environmental pollution caused by degradation of the key intermediate in the sitagliptin bulk drug production process is eliminated.
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Paragraph 0050-0051; 0054-0055
(2021/02/10)
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- SITAGLIPTIN SYNTHESIS
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The present invention relates to novel processes for the preparation of enantiomerically enriched β-amino acid derivatives such as β-amino esters useful for the synthesis of enantiomerically enriched biologically active molecules such as sitagliptin. The key step involves the resolution of the racemate with mandelic acid.
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- PROCESS AND INTERMEDIATES FOR THE PREPARATION OF N-ACYLATED-4-ARYL BETA-AMINO ACID DERIVATIVES
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A process for producing an enantiomerically enriched, pure or enriched and essentially pure compound of Formula I [structure] wherein the R-, or S-configuration at the stereogenic center is marked with an *, which process hydrogenates an enamide compound of formula III [structure] in an organic solvent in the presence of a transition metal precursor complexed to a chiral phosphine ligand catalyst, wherein Ar is phenyl which is unsubstituted or substituted, R1 and R2 are selected from H, Cl - 8 alkyl, C5 - 12 cycloalkyl, aryl and aryl-C 1 - 2-alkyl, or R1 and R2 together with the nitrogen atom to which they are attached form a C4- r member heterocyclic πng system optionally fused with a 5- to 6- member carbocyclic or heterocyclic ring system, and the other substituents are as defined herein.
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Page/Page column 17-18
(2010/08/04)
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- SITAGLIPTIN SYNTHESIS
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The present invention relates to novel processes for the preparation of enantiomerically enriched β -amino acid derivatives such as β -amino esters useful for the synthesis of enantiomerically enriched biologically active molecules such as sitagliptin. The key step involves the resolution of the racemate with mandelic acid.
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Page/Page column 26
(2010/12/17)
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- Application of the asymmetric hydrogenation of enamines to the preparation of a beta-amino acid pharmacophore
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(3R)-3-[N-(tert-Butoxycarbonyl)amino]-4-(2,4,5-trifluorophenyl)butanoic acid 7a has been synthesized by an asymmetric hydrogenation of enamine ester 3 using chiral ferrocenyl ligands I and II in conjunction with [Rh(COD)Cl] 2. The direct reduction of 3 provides amino ester 1b in 93% ee, which was isolated as an (S)-camphorsulfonic acid salt to upgrade the enantiomeric excess to >99%. A more concise approach was developed involving the in situ protection of 1b using di-tert-butyldicarbonate. This approach provided the desired N-Boc amino ester 7b directly from the hydrogenation with 97% ee, which was upgraded to >99% ee upon crystallization.
- Kubryk, Michele,Hansen, Karl B.
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p. 205 - 209
(2007/10/03)
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