- Chemo- and Enantioselective Hydrogenation of α-Formyl Enamides: An Efficient Access to Chiral α-Amido Aldehydes
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In order to effectively synthesize chiral α-amino aldehydes, which have a wide range of potential applications in organic synthesis and medicinal chemistry, a highly chemo- and enantioselective hydrogenation of α-formyl enamides has been developed, catalyzed by a rhodium complex of a P-stereogenic bisphosphine ligand. Under different hydrogen pressures, the chiral α-amido aldehydes and β-amido alcohols were obtained in high yields (97–99 %) and with excellent chemo- and enantioselectivities (up to >99.9 % ee). The hydrogenation can be carried out on a gram scale and with a high substrate/catalyst ratio (up to 20 000 S/C), and the hydrogenated products were further converted into several important chiral products. Computations of the catalytic cycle gave a clear description for the R/S pathways, provided a reasonable explanation for the enantioselectivity, and revealed several other specific features.
- Zhang, Jian,Jia, Jia,Zeng, Xincheng,Wang, Yuanhao,Zhang, Zhenfeng,Gridnev, Ilya D.,Zhang, Wanbin
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p. 11505 - 11512
(2019/07/17)
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- Of enantiomerically enriched indoline - 2 - formic acid
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The invention discloses a synthesis method of enantiomer-enriched indoline-2-formic acid shown in a formula (I). The synthesis method of the enantiomer-enriched indoline-2-formic acid comprises the following steps: by adopting low-cost and available ortho-position halogen substituted benzaldehyde and N-benzoyl substituted glycine as starting materials, carrying out Erlenmeyer-Plochl cyclization, alkaline hydrolysis and asymmetric catalytic hydrogen for constructing a chiral center, and then carrying out acid catalysis, deprotection and cyclization sequentially or cyclization, acid catalysis and deprotection sequentially, so that the enantiomer-enriched indoline-2-formic acid is obtained. The synthesis method of the enantiomer-enriched indoline-2-formic acid has the advantages that raw materials used in the whole process route are low-cost and easily available, harmful substances or multiple danger special processes are not used, reaction conditions are mild, technological operation is simple, production is safe and stable, the product yield is high, the purity is high, less three wastes are produced, and the energy consumption is low, so that the synthesis method of the enantiomer-enriched indoline-2-formic acid is a process route especially applicable to industrial production. The formula (1) is described in the specification.
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- Resolution of Racemic Organic Acids with (1S, 4S)-4[3,4-Dichlorophenyl]-1,2,3,4-Tetrahydro-N-Methyl-1-Naphthaloneamine
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The present invention relates to novel chiral resolving agents and a process for resolution of racemic organic acids and their derivatives of the formula (+, ?)—R1R2CHCOOR3 with Cis-(1S,4S)-4[3,4-dichlorophenyl]-1,2,3,4-tetrahydro-N-methyl-1-naphthaloneamine and its Cis-(1R,4R)-isomer as well as Trans-(1S,4R)-4[3,4-dichlorophenyl]-1,2,3,4-tetrahydro-N-methyl-1-naphthaloneamine and its Trans-(1R,4S)-isomer.
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Page/Page column 3
(2009/10/18)
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- Novel method for the synthesis of s-indoline-2- carboxylic acid and application thereof in the synthesis of perindopril
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Process for the synthesis of (2S)-indoline-2-carboxylic acid of formula (I): Application in the synthesis of perindopril and its pharmaceutically acceptable salts.
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Page/Page column 3
(2008/06/13)
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- PROCESS AND PRODUCT
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A process of preparing perindopril of formula (I), or a pharmaceutically acceptable salt thereof which process comprises protecting a compound of formula (II) where R denotes a hydrogen atom, in the presence of benzene sulphonic acid as a catalyst, to obtain the benzene sulphonic acid salt of an ester of formula (III) where Rl is a carboxyl protecting group and reacting said ester of formula (III) with N-[(S)-1-carbethoxybutyl]-(S)-alanine to obtain a compound of formula (IV) where Rl is as defined above; and deprotecting a compound of formula (IV) to yield perindopril of formula (I), or a pharmaceutically acceptable salt thereof. There is also provided by the present invention the benzene sulphonic acid salt of an ester of formula (III), and perindopril or a pharmaceutically acceptable salt thereof prepared by the above process.
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Page 7; 22; scheme
(2010/02/09)
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- Application of Microbes and Microbial Esterases to the Preparation of Optically Active N-Acetylindoline-2-Carboxylic Acid
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Methylotrophic bacteria, isolated from soil samples or from sewage sludge, proved to be useful sources of esterases for catalyzing the enantioselective hydrolysis of racemic N-acetyl-indoline-2-carboxylic acid methyl ester (7) to the corresponding (2S) or (2R)-N-acetyl amino acid (6) with high optical yields.From the DMF-utilizer Pseudomonas DMF 5/8 and the methanol-utilizer Isolate EE 210, the corresponding esterases were isolated.Reactions with whole cells as well as with the purified enzymes are described.
- Ramos Tombo, Gerardo M.,Schaer, Hans-Peter,Ghisalba, Oreste
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p. 1833 - 1838
(2007/10/02)
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- Process for the asymmetric synthesis of chiral indoline-2-carboxylic acids
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Disclosed herein is a process for producing an asymmetric indoline-2-carboxylic acid of the structural Formula: STR1 wherein X is hydrogen, bromine, chlorine, C1-4 alkyl or C1-4 alkoxy, which comprises: (a) assymetrically reducing an o-nitrophenylpyruvic acid III by contacting the acid III with a reducing complex formed from (R)-proline or (S)-proline, respectively, and sodium borohydride in an inert solvent to form, respectively, an (S) or (R)-α-hydroxy-2-nitrobenzenepropanoic acid IV; (b) reacting, respectively, said (S) or (R)-α-hydroxy-2-nitrobenzenepropanoic acid III with a Vilsmeier chlorinating reagent in which the chlorinating agent thereof is selected from a group consisting of thionyl chloride, oxalyl chloride, phosphorus oxychloride, phosphorus pentachloride and sulfuryl chloride and the amide thereof is selected from a group consisting of dimethylformamide, diethylformamide, dimethylacetamide and diethylacetamide, said reaction being run at temperatures of at least 20° C., in order to obtain, respectively, and (R) or (S)-α-chloro-2-nitrobenzenepropanoic acid IV; (c) reducing the nitro group of said (R) or (S)-α-chloro-2-nitrobenzenepropanoic acid (V) to an amino group; and (d) cyclizing the resulting (R) or (S)-α-chloro-2-aminobenzenepropanoic acid in aqueous base.
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- Substituted iminodiacids, their preparation and pharmaceutical compositions containing them
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Compounds of the general formula: STR1 wherein: the ring A is saturated and n=0 or 1, or the ring A is a benzene ring and n=1, R1 represents a lower alkyl group which can carry an amino group, R2 represents a hydrogen atom or a lower alkyl group, R3 represents a straight or branched alkyl group, a mono- or di-cycloalkylalkyl or phenylalkyl group having no more than a total of 9 carbon atoms, or a substituted alkyl group, and also the salts thereof. These compounds are useful as therapeutic drugs.
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