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37577-07-4Relevant articles and documents
High Regio- and Stereoselective Multi-enzymatic Synthesis of All Phenylpropanolamine Stereoisomers from β-Methylstyrene
Corrado, Maria L.,Knaus, Tanja,Mutti, Francesco G.
, p. 2345 - 2350 (2021)
We present a one-pot cascade for the synthesis of phenylpropanolamines (PPAs) in high optical purities (er and dr up to >99.5 %) and analytical yields (up to 95 %) by using 1-phenylpropane-1,2-diols as key intermediates. This bioamination entails the combination of an alcohol dehydrogenase (ADH), an ω-transaminase (ωTA) and an alanine dehydrogenase to create a redox-neutral network, which harnesses the exquisite and complementary regio- and stereo-selectivities of the selected ADHs and ωTAs. The requisite 1-phenylpropane-1,2-diol intermediates were obtained from trans- or cis-β-methylstyrene by combining a styrene monooxygenase with epoxide hydrolases. Furthermore, in selected cases, the envisioned cascade enabled to obtain the structural isomer (1S,2R)-1-amino-1-phenylpropan-2-ol in high optical purity (er and dr >99.5 %). This is the first report on an enzymatic method that enables to obtain all of the four possible PPA stereoisomers in great enantio- and diastereo-selectivity.
Stereoselective Catalytic Synthesis of Active Pharmaceutical Ingredients in Homemade 3D-Printed Mesoreactors
Rossi, Sergio,Porta, Riccardo,Brenna, Davide,Puglisi, Alessandra,Benaglia, Maurizio
, p. 4290 - 4294 (2017)
3D-printed flow reactors were designed, fabricated from different materials (PLA, HIPS, nylon), and used for a catalytic stereoselective Henry reaction. The use of readily prepared and tunable 3D-printed reactors enabled the rapid screening of devices with different sizes, shapes, and channel dimensions, aimed at the identification of the best-performing reactor setup. The optimized process afforded the products in high yields, moderate diastereoselectivity, and up to 90 % ee. The method was applied to the continuous-flow synthesis of biologically active chiral 1,2-amino alcohols (norephedrine, metaraminol, and methoxamine) through a two-step sequence combining the nitroaldol reaction with a hydrogenation. To highlight potential industrial applications of this method, a multistep continuous synthesis of norephedrine has been realized. The product was isolated without any intermediate purifications or solvent switches.
Regio- and stereoselective multi-enzymatic aminohydroxylation of β-methylstyrene using dioxygen, ammonia and formate
Corrado, Maria L.,Knaus, Tanja,Mutti, Francesco G.
, p. 6246 - 6251 (2019/12/03)
We report an enzymatic route for the formal regio- and stereoselective aminohydroxylation of β-methylstyrene that consumes only dioxygen, ammonia and formate; carbonate is the by-product. The biocascade entails highly selective epoxidation, hydrolysis and hydrogen-borrowing alcohol amination. Thus, β-methylstyrene was converted into 1R,2R and 1S,2R-phenylpropanolamine in 59-63% isolated yields, and up to >99.5 : 0.5 dr and er.
Method for preparing norephedrine and norpseudoephedrine
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Paragraph 0004; 0012; 0013; 0014; 0015, (2017/04/29)
The invention relates to a method for preparing (1R, 2S)-norephedrine, (1R, 2R)-norpseudoephedrine and a midbody thereof. The method comprises the following steps: in the reaction process in the first step, by taking a carrot as a medium, carrying out bio-transforming on 2-oximido-1-phenylacetone and reducing into (R)-2-oximido-1-phenyl propyl alcohol; in the second step, reducing (R)-2-oximido-1-phenyl propyl alcohol into a mixture of (1R, 2S)-norephedrine and (1R, 2R)-norpseudoephedrine; adding a chiral reliquid reagent (R)-O-acetyl mandelic acid and decomposing, thereby acquiring an optical pure (1R, 2S)-norephedrine and (1R, 2R)-norpseudoephedrine monomeric compound.
Efficient 2-step biocatalytic strategies for the synthesis of all nor(pseudo)ephedrine isomers
Sehl, Torsten,Hailes, Helen C.,Ward, John M.,Menyes, Ulf,Pohl, Martina,Rother, Doerte
supporting information, p. 3341 - 3348 (2014/06/10)
Chiral 1,2-amino alcohols are important building blocks for chemistry and pharmacy. Here, we developed two different biocatalytic 2-step cascades for the synthesis of all four nor(pseudo)ephedrine (N(P)E) stereoisomers. In the first one, the combination of an (R)-selective thiamine diphosphate (ThDP)-dependent carboligase with an (S)- or (R)-selective ω-transaminase resulted in the formation of (1R,2S)-NE or (1R,2R)-NPE in excellent optical purities (ee >99% and de >98%). For the synthesis of (1R,2R)-NPE, space-time yields up to ～26 g L-1 d-1 have been achieved. Since a highly (S)-selective carboligase is currently not available for this reaction, another strategy was followed to complement the nor(pseudo)ephedrine platform. Here, the combination of an (S)-selective transaminase with an (S)-selective alcohol dehydrogenase yielded (1S,2S)-NPE with an ee >98% and a de >99%. Although lyophilized whole cells are cheap to prepare and were shown to be appropriate for use as biocatalysts, higher optical purities were observed with purified enzymes. These synthetic enzyme cascade reactions render the N(P)E-products accessible from inexpensive, achiral starting materials in only two reaction steps and without the isolation of the reaction intermediates. This journal is the Partner Organisations 2014.
Stereoselective synthesis of γ-lactams from imines and cyanosuccinic anhydrides
Tan, Darlene Q.,Younai, Ashkaan,Pattawong, Ommidala,Fettinger, James C.,Cheong, Paul Ha-Yeon,Shaw, Jared T.
, p. 5126 - 5129 (2013/10/22)
A reaction between imines and anhydrides has been developed with chiral disubstituted anhydrides and chiral imines. The synthesis of highly substituted γ-lactams with three stereogenic centers, including one quaternary center, proceeds at room temperature in high yield and with high diastereoselectivity in most cases. Enantiomerically pure alkyl-substituted anhydrides proceed with no epimerization, thus providing access to enantiomerically pure penta-substituted lactam products.
Two steps in one pot: Enzyme cascade for the synthesis of nor(pseudo)ephedrine from inexpensive starting materials
Sehl, Torsten,Hailes, Helen C.,Ward, John M.,Wardenga, Rainer,Von Lieres, Eric,Offermann, Heike,Westphal, Robert,Pohl, Martina,Rother, Doerte
, p. 6772 - 6775 (2013/07/26)
Two steps in one pot: An enzyme cascade consisting of a lyase and an (R)- or (S)-selective ω-transaminase (TA) provides (1R,2R)-norpseudoephedrine and (1R,2S)-norephedrine in only two steps. The intermediate is not isolated in this one-pot reaction and the products are obtained in high enantio- and diastereomeric purity. Moreover, the by-product from the second reaction can be recycled to serve as the substrate for the first reaction. Copyright
Stereoselective synthesis of norephedrine and norpseudoephedrine by using asymmetric transfer hydrogenation accompanied by dynamic kinetic resolution
Lee, Hyeon-Kyu,Kang, Soyeong,Choi, Eun Bok
experimental part, p. 5454 - 5460 (2012/08/27)
Each of the enantiomers of both norephedrine and norpseudoephedrine were stereoselectively prepared from the common, prochiral cyclic sulfamidate imine of racemic 1-hydroxy-1-phenyl-propan-2-one by employing asymmetric transfer hydrogenation (ATH) catalyzed by the well-defined chiral Rh-complexes, (S,S)- or (R,R)-Cp*RhCl(TsDPEN), and HCO2H/Et3N as the hydrogen source. The ATH processes are carried out under mild conditions (rt, 15 min) and are accompanied by dynamic kinetic resolution.
Charge-transfer interactions: An efficient tool for recycling bis(oxazoline)-copper complexes in asymmetric henry reactions
Didier, Dorian,Magnier-Bouvier, Caroline,Schulz, Emmanuelle
supporting information; experimental part, p. 1087 - 1095 (2011/07/09)
An anthracenyl-modified chiral bis(oxazoline) copper complex has been demonstrated to efficiently promote nitroaldol reactions between structurally varying aldehydes and nitromethane or nitroethane. The catalyst was recovered through formation of a charge transfer complex between the chiral ligand and trinitrofluorenone and its subsequent precipitation with pentane. The efficiency of this procedure was proved through several consecutive catalytic cycles that allowed the sturdy formation of the expected product with a high enantioselectivity. The catalyst′s stability was also put to the test in an original multi-substrate procedure. Following the same recovery concept, a new heterogeneous procedure was tested for which trinitrofluorenone was covalently linked to a silica support. Asymmetric heterogeneous catalysis was performed under these conditions as one of the few examples demonstrating the potential catalyst recycling in nitroaldol reactions through reversible, non-covalent interactions. Copyright
CATALYTIC HYDROGENATION PROCESS AND NOVEL CATALYST FOR IT
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Page/Page column 3, (2009/05/28)
The present invention provides a novel hydrogenation catalyst, process of preparing the catalyst and process for the preparation of optically active L-norephedrine, [(1R,2S)-2-amino-1-phenyl-1-propanol] by a catalytic hydrogenation process, said catalyst comprising of finely divided nickel metal containing a metal from group III A of the periodic table as an activator and a metal from group VI B or VIII as promoter,