- Synthesis and application of N-3,5-dinitrobenzoyl and C3 symmetric diastereomeric chiral stationary phases
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Three diastereomeric chiral compounds, namely, (R,R)-(+)-2-amino-1,2-diphenylethanol, (1S,2R)-(+)-2-amino-1,2-diphenylethanol, and (1R,2R)-(+)-1,2-diphenylethylenediamine were used as starting materials for preparing three N-3,5-dinitrobenzoyl derivative
- Ryoo, Jae Jeong,Yu, Jeong Jae
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- Method for synthesizing cis-beta-amino acids and derivatives thereof
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The invention belongs to the technical field of synthetic chemistry, and concretely relates to a method for synthesizing cis-beta-amino acids and derivatives thereof. The synthesis method comprises the following steps: providing N-acyloxazolidinone repres
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Paragraph 0098; 0101-0108
(2019/06/07)
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- Synthesis of new C3 symmetric amino acid- and aminoalcohol-containing chiral stationary phases and application to HPLC enantioseparations
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We recently reported a new C3-symmetric (R)-phenylglycinol N-1,3,5-benzenetricarboxylic acid-derived chiral high-performance liquid chromatography (HPLC) stationary phase (CSP 1) that demonstrated better results as compared to a previously described N-3,5-dintrobenzoyl (DNB) (R)-phenylglycinol-derived CSP. Over a decade ago, (S)-leucinol, (R)-phenylglycine, and (S)-leucine derivatives were used as the starting materials of 3,5-DNB-based Pirkle-type CSPs for chiral separation. In this study, three new C3-symmetric CSPs (CSP 2, 3, and 4) were prepared by combining the ideas and results mentioned above. Here we describe the synthetic procedures and applications of the new C3-symmetric CSPs (CSP 2–CSP 4).
- Yu, Jeongjae,Armstrong, Daniel W.,Ryoo, Jae Jeong
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- A practical building block for the synthesis of discodermolide
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A new highly diastereoselective and practical route to the lactone 6a which is used as a key building block for the total synthesis of the microtubule-stabilizing anticancer agent discodermolide is reported. This exploits the chiral auxiliary (4R)-4-isopr
- Loiseleur, Olivier,Koch, Guido,Wagner, Trixie
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supporting information
p. 597 - 602
(2013/09/02)
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- Preparation of protected β2- and β3- homocysteine, β2- and β3-homohistidine, and β2-homoserine for solid-phase syntheses
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The Ser, Cys, and His side chains play decisive roles in the syntheses, structures, and functions of proteins and enzymes. For our structural and biomedical investigations of β-peptides consisting of amino acids with proteinogenic side chains, we needed to have reliable preparative access to the title compounds. The two β3-homoamino acid derivatives were obtained by Arndt-Eistert methodology from Boc-His(Ts)-OH and Fmoc-Cys(PMB)-OH (Schemes 2-4), with the side-chain functional groups' reactivities requiring special precautions. The β2-homoamino acids were prepared with the help of the chiral oxazolidinone auxiliary DIOZ by diastereoselective aldol additions of suitable Ti-enolates to formaldehyde (generated in situ from trioxane) and subsequent functional-group manipulations. These include OH → OtBu etherification (for β2hSer; Schemes 5 and 6), OH → STrt replacement (for β2hCys; Scheme 7), and CH 2OH → CH2N3 → CH2NH 2 transformations (for β2hHis; Schemes 9-11). Including protection/deprotection/re-protection reactions, it takes up to ten steps to obtain the enantiomerically pure target compounds from commercial precursors. Unsuccessful approaches, pitfalls, and optimization procedures are also discussed. The final products and the intermediate compounds are fully characterized by retention times (tR), melting points, optical rotations, HPLC on chiral columns, IR, 1H- and 13C-NMR spectroscopy, mass spectrometry, elemental analyses, and (in some cases) by X-ray crystal-structure analysis.
- Lelais, Gerald,Micuch, Peter,Josien-Lefebvre, Delphine,Rossi, Francesco,Seebach, Dieter
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p. 3131 - 3159
(2007/10/03)
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- Asymmetric alkylations using SuperQuat auxiliaries - An investigation into the synthesis and stability of enolates derived from 5,5-disubstituted oxazolidin-2-ones
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Studies on the alkylation of enolates derived from a range of N-acyl-5,5-dimethyloxazolidin-2-ones and N-acyl-5,5-diphenyloxazolidin-2-ones reveal that high yields and high diastereoselectivities are best obtained when homochiral 4-isopropyl-5,5-dimethyloxazolidin-2-one is employed as a chiral auxiliary.
- Bull, Steven D.,Davies, Stephen G.,Jones, Simon,Sanganee, Hitesh J.
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p. 387 - 398
(2007/10/03)
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