37088-64-5Relevant academic research and scientific papers
Asymmetric synthesis of β-lactam via palladium-catalyzed enantioselective intramolecular c(sp3)-h amidation
Tong, Hua-Rong,Zheng, Wenrui,Lv, Xiaoyan,He, Gang,Liu, Peng,Chen, Gong
, p. 114 - 120 (2019/12/24)
β-Lactams are important scaffolds in drug design and frequently used as reactive intermediates in organic synthesis. Catalytic reactions featuring intramolecular C-H amidation of alkyl carboxamide substrates could provide a straightforward disconnection strategy for β-lactam synthesis. Herein, we report a streamlined method for asymmetric synthesis of β-aryl β-lactams from propanoic acid and aryl iodides via Pd-catalyzed sequential C(sp3)-H functionalization. The lactam-forming reaction provides an example of PdII-catalyzed enantioselective intramolecular C(sp3)-H amidation reaction and proceeds up to 94% ee. The use of a 2-methoxy-5-chlorophenyl iodide oxidant is critical to control the competing reductive elimination pathways of the PdIV intermediate to achieve the desired chemoselectivity. Mechanistic studies suggest that both steric and electronic effects of the unconventional aryl iodide oxidant are responsible for controlling the competing C-N versus C-C reductive elimination pathways of the PdIV intermediate.
RETRACTED ARTICLE: Site-selective enzymatic C-H amidation for synthesis of diverse lactams
Cho, Inha,Jia, Zhi-Jun,Arnold, Frances H.
, p. 575 - 578 (2019/06/07)
A major challenge in carbon?hydrogen (C?H) bond functionalization is to have the catalyst control precisely where a reaction takes place. In this study, we report engineered cytochrome P450 enzymes that perform unprecedented enantioselective C?H amidation reactions and control the site selectivity to divergently construct b-, g-, and d-lactams, completely overruling the inherent reactivities of the C?H bonds. The enzymes, expressed in Escherichia coli cells, accomplish this abiological carbon?nitrogen bond formation via reactive iron-bound carbonyl nitrenes generated from nature-inspired acyl-protected hydroxamate precursors. This transformation is exceptionally efficient (up to 1,020,000 total turnovers) and selective (up to 25:1 regioselectivity and 97%, please refer to compound 2v enantiomeric excess), and can be performed easily on preparative scale.
HPLC enantioseparation on a homochiral MOF-silica composite as a novel chiral stationary phase
Tanaka, Koichi,Muraoka, Toshihide,Otubo, Yasuhiro,Takahashi, Hiroki,Ohnishi, Atsushi
, p. 21293 - 21301 (2016/03/08)
The last frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal-organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performance liquid chromatography to separate the enantiomers of various kinds of racemic sulfoxides, sec-alcohols, β-lactams, benzoins, flavanones and epoxides. The experimental results showed excellent performances for enantioseparation, and highlighted that enantioseparation on homochiral MOF columns is practical.
Studies on N-activation for the lipase-catalyzed enantioselective preparation of β-amino esters from 4-phenylazetidin-2-one
Sundell, Riku,Kanerva, Liisa T.
, p. 1500 - 1506 (2015/03/04)
The effect of N-substitution was examined for the enantio-selective lipase-catalyzed ring-opening reaction of racemic 4-phenylazetidin-2-one with methanol in dry organic solvents. Marked differences in the reactivity of various N-protected 4-phenylazetidin-2-ones were observed. Preparativescale reactions with Candida antarctica lipase B (Novozym 435 preparation) yielded N-acylated methyl (R)-3-amino-3- phenylpropanoates with enantiomeric excess (ee) values >99% in up to a 49% isolated yield, whereas Thermomyces lanuginosus lipase (Lipozyme TM IM) gave enantiomerically enriched methyl (S)-3-acetamido-3-phenylpropanoate. Candida antarctica lipase A catalyzed the cleavage of the N-chloroacetyl protective group, whereas all of the other examined lipases underwent the ring-opening reaction.
Process for preparation of enantiomerically pure S-(+)-N, N-dimethyl-a-[2-(naphthalenyloxy)ethyl] benzenemethanamine
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, (2014/07/09)
The present invention relates to improved, efficient process for the preparation of enantiomerically pure S-(+)-N,N-dimethyl-a-[2-(naphthalenyloxy)ethyl] benzenemethanamine and pharmaceutically acid addition salts thereof. The present invention particularly provides a process for preparation of (3S, 4R)-3-hydroxy-1-(4-methoxyphenyl)-4-phenylazetidin-2-one useful as a key intermediate for preparation of (s)-dapoxetine.
Homochiral coordination polymers with nanotubular channels for enantioselective sorption of chiral guest molecules
Tanaka, Koichi,Kikumoto, Yuki,Hota, Naoki,Takahashi, Hiroki
supporting information, p. 880 - 883 (2014/03/21)
Two novel chiral coordination polymers were synthesized by treating C 2-symmetric 2,2′-dihydroxy- and 2,2′-dimethoxy-1, 1′-binaphthalene-3,3′-dicarboxylic acids with Cu2+, in which sorption of some chiral β-lactam compounds in the fr
Catalytic, enantioselective N-acylation of lactams and thiolactams using amidine-based catalysts
Yang, Xing,Bumbu, Valentina D.,Liu, Peng,Li, Ximin,Jiang, Hui,Uffman, Eric W.,Guo, Lei,Zhang, Wei,Jiang, Xuntian,Houk,Birman, Vladimir B.
supporting information, p. 17605 - 17612 (2013/01/15)
In contrast to alcohols and amines, racemic lactams and thiolactams cannot be resolved directly via enzymatic acylation or classical resolution. Asymmetric N-acylation promoted by amidine-based catalysts, particularly Cl-PIQ 2 and BTM 3, provides a convenient method for the kinetic resolution of these valuable compounds and often achieves excellent levels of enantioselectivity in this process. Density functional theory calculations indicate that the reaction occurs via N-acylation of the lactim tautomer and that cation-π interactions play a key role in the chiral recognition of lactam substrates.
SmI2-promoted imino-Reformatsky reaction for facile synthesis of enantioenriched β-amino acid esters
Wang, Li,Shen, Chun,Xu, Ming-Hua
, p. 61 - 65 (2011/12/15)
A facile and efficient method for the stereoselective synthesis of β-amino acid esters via SmI2-promoted imino-Reformatsky reaction is described. Asymmetric addition of tert-butyl bromoacetate to N-tert-butanesulfinyl aldimines afforded β-amino
Kinetic resolution of β-lactams via enantioselective N-acylation
Yang, Xing,Bumbu, Valentina D.,Birman, Vladimir B.
experimental part, p. 4755 - 4757 (2011/11/04)
Enantioselective N-acylation of 4-aryl-β-lactams in the presence of acyl transfer catalyst Cl-PIQ provides an effective method for their non-enzymatic kinetic resolution.
Comparison of separation performances of amylose- and cellulose-based stationary phases in the high-performance liquid chromatographic enantioseparation of stereoisomers of β-lactams
Pataj, Zoltan,Ilisz, Istvan,Berkecz, Robert,Forro, Eniko,Fueloep, Ferenc,Peter, Antal
experimental part, p. 120 - 128 (2010/09/10)
High-performance liquid chromatographic methods were developed for the separation of the enantiomers of 19 β-lactams. The direct separations were performed on chiral stationary phases containing either amylose-tris-3,5- dimethylphenyl carbamate, (Kromasil
