- A mild and highly efficient synthesis of chiral N-dichloroacetyl-4-ethyl-1, 3-oxazolidines
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Chiral 2-amino-butanols (4 and 5) were obtained via the isolation of diastereomeric salt. Then, chiral compounds (6-9) were synthesized by a sequential procedure involving condensation of chiral 2-amino-butanol with ketone and dichloroacetyl chloride. All the compounds were characterized by IR, 1H NMR, 13C NMR, and element analysis. The absolute configurations of (S)-8 was determined by X-ray crystallography.
- Zhao, Li-Xia,Fu, Ying,Ye, Fei,Gao, Shuang
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Read Online
- Preparation, characterization and performance evaluation of separation of alcohol using crosslinked membrane materials
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In the present study the glutaraldehyde-crosslinked chitosan membrane (GXCM) was prepared and chiral resolution of (R,S)-2-amino-1-butanol (2A1B) was performed. The membrane was analyzed by Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) for its chemical composition. The morphology of the membrane was studied by Scanning Electron Microscopy (SEM) and correlated with membrane performance. The performance of the GXCM membrane was quantified by performing chiral resolution of (R,S)-2-amino-1-butanol in pressure driven separation and the influences of permeation parameters such as operating pressure, concentration of feed solutions, concentration of copper(ii) ions were investigated to understand the chiral selectivity of the membrane. The optical resolution of (R,S)-2-amino-1-butanol racemic mixture, 92% of enantiomeric excess (% ee) was achieved. The separation ability of the above crosslinked membrane was also investigated, and a separation factor of up to 5.6 was achieved.
- Ingole, Pravin G.,Thakare, Neha R.,Kim, Keehong,Bajaj, Hari C.,Singh, Kripal,Lee, Hyungkeun
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Read Online
- Enantioselective Cascade Biocatalysis for Deracemization of Racemic β-Amino Alcohols to Enantiopure (S)-β-Amino Alcohols by Employing Cyclohexylamine Oxidase and ω-Transaminase
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Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg?1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L?1) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.
- Zhang, Jian-Dong,Chang, Ya-Wen,Dong, Rui,Yang, Xiao-Xiao,Gao, Li-Li,Li, Jing,Huang, Shuang-Ping,Guo, Xing-Mei,Zhang, Chao-Feng,Chang, Hong-Hong
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p. 124 - 128
(2020/09/21)
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- Selective hydrogenation of primary amides and cyclic di-peptides under Ru-catalysis
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A ruthenium(II)-catalyzed selective hydrogenation of challenging primary amides and cyclic di-peptides to their corresponding primary alcohols and amino alcohols, respectively, is reported. The hydrogenation reaction operates under mild and eco-benign conditions and can be scaled-up.
- Subaramanian, Murugan,Sivakumar, Ganesan,Babu, Jessin K.,Balaraman, Ekambaram
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supporting information
p. 12411 - 12414
(2020/10/30)
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- Data mining of amine dehydrogenases for the synthesis of enantiopure amino alcohols
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Chiral amino alcohols are essential building blocks for the pharmaceutical industry, and are widely present in natural and synthetic bioactive compounds. Amine dehydrogenases (AmDHs) can asymmetrically reduce prochiral ketones with low-cost ammonia to chiral amines and water as by-products, using NAD(P)H as a cofactor under mild conditions, but hydroxy ketones with formation of chiral hydroxy amines have rarely been investigated. In this study, six new bacterial AmDHs derived from amino acid dehydrogenases (AADHs) were identified by data mining, and five out of the six enzymes were able to efficiently reduce 1-hydroxybutan-2-one (1a) to (S)-2-aminobutan-1-ol ((S)-2a) with 19-99% conversions and 99% ee. The five AmDHs were purified and biochemically characterized for reductive amination activity towards substrate 1a with the optimal pH at 8.5 or 9.0 and the optimal temperature at 45 °C, 50 °C or 55 °C, and provided reductive amination of a broad range of prochiral α-hydroxy ketones, and even of a model β-hydroxy ketone leading to β-hydroxy amine with 99% ee. Our study expands the toolbox of AmDHs in the synthesis of chiral amino alcohols.
- Guo, Jinggong,Li, Jun-Kuan,Ma, Jun-An,Miao, Yuchen,Qu, Ge,Sun, Zhoutong,Wang, Hongyue
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p. 5945 - 5952
(2020/10/08)
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- Continuous-flow protocol for the synthesis of enantiomerically pure intermediates of anti epilepsy and anti tuberculosis active pharmaceutical ingredients
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Continuous-flow production of chiral intermediates plays an important role in the development of building blocks for Active Pharmaceutical Ingredients (APIs), being α-amino acids and their derivatives widely applied as building blocks. In this work we developed two different strategies for the synthesis of intermediates used on the synthesis of levetiracetam/brivaracetam and ethambutol. The results obtained show that methionine methyl ester can be continuously converted to the desired ethambutol intermediate by RANEY Nickel dessulfurization/reduction strategy whereas levetiracetam/brivaracetam intermediates could be synthesized by both RANEY Nickel (without H2) and Pd/C-H2 approach or by photochemical desulfurization.
- Aguiar, Renata M.,Le?o, Raquel A. C.,Mata, Alejandro,Cantillo, David,Kappe, C. Oliver,Miranda, Leandro S. M.,De Souza, Rodrigo O. M. A.
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supporting information
p. 1552 - 1557
(2019/02/14)
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- Chiral resolution method for preparing L-2-amino-1-butanol
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The invention relates to a chiral resolution method for preparing L-2-amino-1-butanol. The method concretely comprises the following steps: a) carrying out multi-step derivatization on (1S,2S)-1,2-cyclohexanediamine used as a precursor to prepare a target chiral resolving agent; b) dissolving a racemic compound 2-amino-1-butanol in an ethanol/water mixed solution, and mixing the obtained solution with equimolar amounts of the chiral resolving agent and copper chloride to precipitate a blue solid; and c) carrying out reduced pressure rotary evaporation to remove the ethanol in the mixed solution, extracting with ethyl acetate, concentrating obtained filtrate, and performing vacuum drying to obtain the optically pure levo compound 2-amino-1-butanol with the ee value reaching up to 99.0% or more. The chiral resolving agent has the advantages of simple synthesis process, mild reaction conditions, high optical purity of the product, cost saving, and suitableness for industrial resolution.
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Paragraph 0015-0016
(2019/10/04)
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- Asymmetric ring opening of racemic epoxides for enantioselective synthesis of (S)-β-amino alcohols by a cofactor self-sufficient cascade biocatalysis system
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A novel one-pot epoxide hydrolase/alcohol dehydrogenase/transaminase cascade process for the asymmetric ring opening of racemic epoxides to enantiopure β-amino alcohols is reported. The product (S)-β-amino alcohols were obtained in 97-99% ee and 79-99% conversion from readily available racemic epoxides.
- Zhang, Jian-Dong,Yang, Xiao-Xiao,Jia, Qiao,Zhao, Jian-Wei,Gao, Li-Li,Gao, When-Chao,Chang, Hong-Hong,Wei, Wen-Long,Xu, Jian-He
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- Enantioselective Synthesis of Chiral Vicinal Amino Alcohols Using Amine Dehydrogenases
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Chiral vicinal amino alcohols are an important motif found in many biologically active molecules. In this study, biocatalytic reductive amination of α-hydroxy ketones with ammonia was investigated using engineered amine dehydrogenases (AmDHs) derived from the leucine amino acid dehydrogenase (AADH) from Lysinibacillus fusiformis. The AmDHs thus identified enabled the synthesis of (S)-configured vicinal amino alcohols from the corresponding α-hydroxy ketones in up to 99% conversions and >99% ee. One of the AmDH variants was used to prepare a key intermediate for the antituberculosis pharmaceutical ethambutol.
- Chen, Fei-Fei,Cosgrove, Sebastian C.,Birmingham, William R.,Mangas-Sanchez, Juan,Citoler, Joan,Thompson, Matthew P.,Zheng, Gao-Wei,Xu, Jian-He,Turner, Nicholas J.
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p. 11813 - 11818
(2019/12/02)
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- Method for synthesizing S-(+)-2-aminobutanol by catalyzing hydrogenation of S-(+)-2-aminobutyric acid
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The invention relates to a method for synthesizing S-(+)-2-aminobutanol by catalyzing hydrogenation of S-(+)-2-aminobutyric acid. According to the method, a product S-(+)-2-aminobutanol is prepared from S-(+)-2-aminobutyric acid through catalytic hydrogenation under acidic conditions by taking water as a solvent and Ru-X-Y/AC as a catalyst; X represents one of Pt and Pd in the Ru-X-Y/AC catalyst, Y represents one of Cu, Mn and Fe, and the loading amounts of three metals of Ru, X and Y respectively are 3%t%-5wt%, 0.1wt%-1wt% and 0.1wt%-1wt%. According to the method, the relatively high yield can be realized at a relatively low pressure and temperature, the reaction time is greatly shortened, the energy consumption is reduced, and the catalyst is good in stability and can be repeatedly used.
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Paragraph 0046-0049
(2017/09/01)
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- L - 2 - amino butyl alcohol synthesis method
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The invention provides a synthetic method of L-2-aminobutanol. The method adopting L-2-aminobutyric acid as an initial raw material comprises the following steps: adding L-2-aminobutyric acid, water, an acid and a catalyst to a high-pressure reaction tank, displaying by using nitrogen, introducing hydrogen, and carrying out a high-pressure hydrogenation reduction reaction; and filtering after the reaction is completed to remove the catalyst, carrying out reduced pressure distillation to remove water, adding an alkali to neutralize, adding alcohols to desalt, carrying out reduced pressure distillation to remove ethanol, and rectifying to obtain the L-2-aminobutanol product. The method has the advantages of cheap and easily available reaction raw materials, few reaction steps, low production cost, simple process, small pollution, and facilitation of realization of industrial production.
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Paragraph 0024-0025
(2017/08/25)
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- Method for synthesizing (S)-2-aminobutanol
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The invention provides a method for synthesizing (S)-2-aminobutanol. The method sequentially comprises steps as follows: (1) a supported metal catalyst is prepared; (2), (S)-2-aminobutanol is dissolved in deionized water, the pH (potential of hydrogen) value is adjusted to be 1-5, and the supported metal catalyst is added; hydrogen is introduced, the reaction temperature is controlled in the range from 60 DEG C to 70 DEG C, the reaction pressure is 2-4 MPa, and the mixture continuously reacts for 4-10 hours in the hydrogen atmosphere until hydrogen absorption stops; (3) after the reaction ends, the catalyst is separated from a reaction liquid, and a finished product (S)-2-aminobutanol is obtained through aftertreatment of filtrate. The method is low in production cost and simple and convenient to operate, raw materials are simple and easy to obtain, little pollution is caused to the environment, the operation is safety, the production yield is high, and the product quality is stable.
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Paragraph 0081; 0082; 0083; 0084; 0085
(2016/12/07)
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- Design, Synthesis, Fungicidal Activity, and Unexpected Docking Model of the First Chiral Boscalid Analogues Containing Oxazolines
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Chirality greatly influences the biological and pharmacological properties of a pesticide and will contribute to unnecessary environmental loading and undesired ecological impact. No structure and activity relationship (SAR) of enantiopure succinate dehydrogenase inhibitors (SDHIs) was documented during the structure optimization of boscalids. On the basis of commercial SDHIs, oxazoline natural products, and versatile oxazoline ligands in organic synthesis, the first effort was devoted to explore the chiral SDHIs and the preliminary mechanism thereof. Fine-tuning furnished chiral nicotinamides 4ag as a more promising fungicidal candidate against Rhizoctonia solani, Botrytis cinerea, and Sclerotinia sclerotiorum, with EC50 values of 0.58, 0.42, and 2.10 mg/L, respectively. In vivo bioassay and molecular docking were investigated to explore the potential in practical application and plausible novelty in action mechanism, respectively. The unexpected molecular docking model showed the different chiral effects on the binding site with the amino acid residues. This chiral nicotinamide also featured easy synthesis and cost-efficacy. It will provide a powerful complement to the commercial SDHI fungicides with the introduction of chirality.
- Li, Shengkun,Li, Dangdang,Xiao, Taifeng,Zhang, Shasha,Song, Zehua,Ma, Hongyu
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p. 8927 - 8934
(2016/12/07)
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- Efficient continuous kinetic resolution of racemic 2-aminobutanol over immobilized penicillin G acylase
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In this paper, an efficient method was established for continuous kinetic resolution of racemic 2-aminobutanol by selective hydrolysis of N-phenylacetyl (±)-2-aminobutanol over immobilized penicillin G acylase (PGA) in a fixed-bed reactor. Several N-acylated derivatives of 2-aminobutanol were screened in batch experiments, and it was found that the hydrolysis of N-phenylacetyl (±)-2-aminobutanol proceeded smoothly in the presence of immobilized penicillin G acylase with satisfied enantioselectivity. Thus, the reaction parameters were optimized in a fixed-bed reactor. Under the optimized conditions, 39.3% conversion of N-phenylacetyl (±)-2-aminobutanol and 98.2% ee value of S-2-aminobutanol were obtained. This fixed-bed system was operated continuously for 40?h without significant decrease of enzyme activity. It has been demonstrated to be more efficient compared to the batch experiments.
- Wang, Jianxin,Liu, Na,Cheng, Xiaobo,Chen, Ligong
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supporting information
p. 956 - 962
(2016/07/07)
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- Palladium-N-heterocyclic carbene (NHC)-catalyzed asymmetric synthesis of indolines through regiodivergent C(sp3)-H activation: Scope and DFT study
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Two bulky, chiral, monodentate N-heterocyclic carbene ligands were applied to palladium-catalyzed asymmetric C-H arylation to incorporate C(sp3)-H bond activation. Racemic mixtures of the carbamate starting materials underwent regiodivergent reactions to afford different trans-2,3- substituted indolines. Although this CAr-Calkyl coupling requires high temperatures (140-160°C), chiral induction is high. This regiodivergent reaction, when carried out with enantiopure starting materials, can lead to single structurally different enantiopure products, depending on the catalyst chirality. The C-H activation at a tertiary center was realized only in the case of a cyclopropyl group. No C-H activation takes place alpha to a tertiary center. A detailed DFT study is included and analyses of methyl versus methylene versus methine C-H activation is used to rationalize experimentally observed regio- and enantioselectivities.
- Katayev, Dmitry,Larionov, Evgeny,Nakanishi, Masafumi,Besnard, Cline,Kündig, E. Peter
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supporting information
p. 15021 - 15030
(2015/02/19)
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- Synthesis of imidacloprid derivatives with a chiral alkylated imidazolidine ring and evaluation of their insecticidal activity and affinity to the nicotinic acetylcholine receptor
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A series of imidacloprid (IMI) derivatives with an alkylated imidazolidine ring were asymmetrically synthesized to evaluate their insecticidal activity against adult female housefly, Musca domestica, and affinity to the nicotinic acetylcholine receptor of the flies. The bulkier the alkyl group, the lower was the receptor affinity, but the derivatives methylated and ethylated at the R-5-position of the imidazolidine ring were equipotent to the unsubstituted compound. Quantitative structure-activity relationship (QSAR) analysis of the receptor affinity demonstrated that the introduction of a substituent into the imidazolidine ring was fundamentally disadvantageous, but the introduction of a substituent at the R-5-position was permissible in the case of its small size. The binding model of the synthesized derivatives with the receptor supported the QSAR analysis, indicating the existence of space for a short alkyl group around the R-5-position in the ligand-binding site. In addition, positive correlation was observed between the insecticidal activity and receptor affinity, suggesting that the receptor affinity was the primary factor in influencing the insecticidal activity even if the imidazolidine ring was modified.
- Nishiwaki, Hisashi,Kuriyama, Mituhiro,Nagaoka, Hikaru,Kato, Akira,Yamauchi, Satoshi,Shuto, Yoshihiro,Akamatsu, Miki
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p. 6305 - 6312,8
(2012/12/11)
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- Enantiopure cyclic O-substituted phenylphosphonothioic acid: Synthesis and chirality-recognition ability
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As a new acidic selector (resolving agent), we synthesized an enantiopure O-alkyl phenylphosphonothioic acid with a seven-membered ring ((R)-5), which was designed on the basis of the results for the enantioseparation of 1-arylethylamine derivatives with acyclic O-ethyl phenylphosphonothioic acid (I). The phosphonothioic acid (R)-5 showed unique chirality-recognition ability in the enantioseparation of 1-naphthylethylamine derivatives, aliphatic secondary amines, and amino alcohols; the ability was complementary to that of I. The X-ray crystallographic analyses of the less- and more-soluble diastereomeric salts showed that hydrogen-bonding networks in the salt crystals are 21-column-type with a single exception which is cluster-type. In the cases of the 21-column-type crystals, stability of the crystals is firstly governed by hydrogen bonds to form a 21-column and secondly determined by intra-columnar T-shaped CH/π interaction(s), intra-columnar hydrogen bond(s), inter-columnar van der Waals interaction and/or inter-columnar T-shaped CH/π interaction(s). In contrast, the cluster-type salt crystal is stabilized by the assistance of inter-cluster T-shaped CH/π and van der Waals interactions. To realize still more numbers of intra- and inter-columnar and -cluster T-shaped CH/π interactions, the seven-membered ring of (R)-5 plays a considerable role. Copyright
- Ribeiro, Nigel,Kobayashi, Yuka,Maeda, Jin,Saigo, Kazuhiko
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experimental part
p. 438 - 448
(2012/01/02)
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- COMPOSITIONS AND METHODS FOR CYCLOFRUCTANS AS SEPARATION AGENTS
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The present invention relates to derivatized cyclofructan compounds, compositions comprising derivatized cyclofructan compounds, and methods of using compositions comprising derivatized cyclofructan compounds for chromatographic separations of chemical species, including enantiomers. Said compositions may comprise a solid support and/or polymers comprising derivatized cyclofructan compounds.
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Page/Page column 45-49; 59
(2010/12/31)
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- Enantioselective synthesis of (S,S)-ethambutol using proline-catalyzed asymmetric α-aminooxylation and α-amination
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An efficient enantioselective synthesis of (S,S)-ethambutol, a tuberculostatic antibiotic, has been achieved in 99% ee via both proline-catalyzed α-aminooxylation and α-amination of n-butyraldehyde as the key step.
- Kotkar, Shriram P.,Sudalai, Arumugam
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p. 1738 - 1742
(2007/10/03)
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- New, convenient methods of synthesis and resolution of 1,2-amino alcohols
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Oximes of α-keto esters are reduced to obtain the corresponding amino alcohols using NaBH4 in combination with I2, CH 3COOH, TiCl4, ZrCl4, COCl2, H 2SO4, and TMS-Cl in 60-85% yields. The racemic phenylglycinol, phenylalaninol, and 2-aminobutanol are resolved using dibenzoyl-L-tartaric acid to obtain enantiomeric samples of >98% ee.
- Periasamy, Mariappan,Sivakumar, Sangarappan,Reddy, Meda Narsi
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p. 1965 - 1967
(2007/10/03)
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- Amino alcohol derivatives, method of producing said derivatives and medicaments containing them
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Compounds of formula I in which R1denotes hydrogen or methyl R2denotes lower straight-chained or branched alkyl with 1 to 10 carbon atoms R3denotes hydrogen or lower alkyl n denotes 0-12 R4denotes alkyl, alkenyl or alkinyl with 6 to 24 carbon atoms, processes for the production thereof as well as pharmaceutical agents containing these compounds for the treatment of osteoporosis.
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- Process for the selective enzymatic hydroxylation of aldehydes and ketones
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A process for the selective enzymatic hydroxylation of aldehydes and ketones using chiral anchor-protective groups.
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- Dynamic kinetic asymmetric transformation of diene monoepoxides: A practical asymmetric synthesis of vinylglycinol, vigabatrin, and ethambutol
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The ability to perform a dynamic kinetic asymmetric transformation (DYKAT) using the palladium-catalyzed asymmetric allylic alkylation (AAA) is explored in the context of butadiene monoepoxide. The versatility of this commercially available, but racemic, four-carbon building block becomes significantly enhanced via conversion of both enantiomers into a single enantiomeric product. The concept is explored in the context of a synthesis of vinylglycinol with phthalimide as the nitrogen source. The success of the project required a new design of the ligand for palladium wherein additional conformational restraints were introduced. Thus, the phthalimide derivative of vinylglycinol was obtained in nearly quantitative yield and had an ee of 98% which, upon crystallization, was enhanced to > 99%. This one-step synthesis of a protected form of vinylglycinol provided short practical syntheses of the title compounds. Vigabatrin requires only four steps, and ethambutol six. The intermediate to the existing synthesis of ethambutol is available in 87% yield in three steps. (R)-Serine derives from oxidative cleavage of the double bond. The reaction of phthalimide and isoprene monoepoxide demonstrates the remarkable ability of the chiral ligands to control both regioselectivity and enantioselectivity and demonstrates the effectiveness of this protocol in creating a quaternary center asymmetrically.
- Trost, Barry M.,Bunt, Richard C.,Lemoine, Remy C.,Calkins, Trevor L.
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p. 5968 - 5976
(2007/10/03)
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- A general synthesis of enantiopure 1,2-aminoalcohols via chiral morpholinones
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Eleven optically active 1,2-aminoalcohols 20a-i and 26b-c were prepared from D-phenylglycine via cyclic imines 7b-i (or enamine 7a). The key step of the strategy is the diastereoselective reduction of chiral oxazinones 7a-i.
- Segat-Dioury, Fabienne,Lingibé, Olivier,Graffe, Bernadette,Sacquet, Marie-Claude,Lhommet, Gérard
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p. 233 - 248
(2007/10/03)
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- Resolution of racemic 2-amino-1-butanol with immobilised penicillin G acylase
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Racemic 2-amino-1-butanol has been resolved to obtain (S)-2-amino-1- butanol with >99% e.e. via enantioselective hydrolysis of its N-phenylacetyl derivative with penicillin G acylase immobilised on Eupergit C. (C) 1999 Elsevier Science Ltd.
- Fadnavis,Sharfuddin, Mohd.,Vadivel
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p. 4495 - 4500
(2007/10/03)
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- ASYMMETRIC SYNTHESIS WITH CHIRAL HYDROGENOLYSABLE AMINES: A NEW ROUTE TO ENANTIOPURE ETHANOLAMINES
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Enantiopure ethanolamines have been obtained via diastereoselective reduction of chiral 2,3-dihydro-6H-1,4-oxazin-2-ones.
- Lingibe, Olivier,Graffe, Bernadette,Sacquet, Marie-Claude,Lhommet, Gerard
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p. 1469 - 1472
(2007/10/02)
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- Reaction of (R)-pantolactone esters of alpha-bromoacids with amines. A remarkable synthesis of optically active alpha-amino esters
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(R)-Pantolactone esters of racemic α-bromo acids react with amines to give α-amino esters having the (S)-configuration at the α-carbon in yields which are considerably greater than the 50% expected on the basis of a simple S(N)2 displacement reaction.
- Koh,Ben,Durst
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p. 4473 - 4476
(2007/10/02)
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- Aldehyde derivatives and their use as calpain inhibitors
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Aldehyde derivatives with a specific calpain inhibiting activity and a platelet-aggregation inhibiting effect with formula (I) or formula (II): wherein R1 represents an aromatic hydrocarbon group, a heterocyclic group, or a group of-X-R3 in which X represents O,-S(O)m-(m = 0, 1, or 2), and R3 represents an aromatic hydrocarbon group, a heterocyclic group, or an alkyl group; Z represents R?-Y-or R?O-CH(R?)-in which Y represents a 3-to 7-membered nitrogen-containing saturated heterocyclic group, or a single cyclic saturated hydrocarbon group, R? represents an alkyl group, an alkenyl group, an alkynyl group, an acyl group, a sulfonyl group, an alkoxycarbonyl group, a carbamoyl group, or a thiocarbamoyl group, R? represents hydrogen, an alkyl group, or an aromatic hydrocarbon group, and R? represents an acyl group, a carbamoyl group, a thiocarbamoyl group, or an alkyl group; and n is an integer of 1 to 5. wherein R?, R?, R?, and R1? are defined in the specification.
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- Lipase-Catalyzed Resolution of Chiral 2-Amino 1-Alcohols
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Lipase-catalyzed resolution of 2-amino 1-alcohols was readily accomplished provided that the amino group was protected as an N-alkoxycarbonyl derivative.Racemic 2-amino-1-butanol and 2-amino-1-propanol were chosen as model compounds, and the resolution was achieved both by hydrolysis of their ester derivatives and by transesterification in ethyl acetate.In either case the (R) enantiomers reacted faster, and at low conversion, the (R) form in high optical purity was obtained as alcohol by hydrolysis and as acetate by transesterification.The two procedures can therefore be considered as complementary with respect to the final product composition.By using commercially available lipase preparations both (R)-(-) and (S)-(+) enantiomers of 2-amino 1-alcohols were isolated in high enantiomeric excesses (95percent).
- Francalanci, Franco,Cesti, Pietro,Cabri, Walter,Bianchi, Daniele,Martinengo, Tiziano,Foa, Marco
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p. 5079 - 5082
(2007/10/02)
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