- Investigation into the enantioselective protonation of enolate Schiff bases with (R)-pantolactone
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The effect of several factors on the enantioselective protonation of the enolates of α-amino acid derivatives with (R)-pantolactone were studied. The highest stereoselectivity (74-76% e.e.) was generally observed by associating lithium chloride with LHMDS
- Calmes, Monique,Glot, Christele,Martinez, Jean
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- Amino Acid Schiff Base Bearing Benzophenone Imine As a Platform for Highly Congested Unnatural α-Amino Acid Synthesis
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Unnatural α-amino acids are invaluable building blocks in synthetic organic chemistry and could upgrade the function of peptides. We developed a new mode for catalytic activation of amino acid Schiff bases, serving as a platform for highly congested unnatural α-amino acid synthesis. The redox active copper catalyst enabled efficient cross-coupling to construct contiguous tetrasubstituted carbon centers. The broad functional group compatibility highlights the mildness of the present catalysis. Notably, we achieved successive β-functionalization and oxidation of amino acid Schiff bases to afford dehydroalanine derivatives bearing tetrasubstituted carbon. A three-component cross-coupling reaction of an amino acid Schiff base, alkyl bromides, and styrene derivatives demonstrated the high utility of the present method. The diastereoselective reaction was also achieved using menthol derivatives as a chiral auxiliary, delivering enantiomerically enriched α-amino acid bearing α,β-continuous tetrasubstituted carbon. The synthesized highly congested unnatural α-amino acid could be derivatized and incorporated into peptide synthesis.
- Matsumoto, Yohei,Sawamura, Jun,Murata, Yumi,Nishikata, Takashi,Yazaki, Ryo,Ohshima, Takashi
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Read Online
- CYCLIZED SULFAMOYLARYLAMIDE DERIVATIVES AND THE USE THEREOF AS MEDICAMENTS FOR THE TREATMENT OF HEPATITIS B
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Inhibitors of HBV replication of Formula (I-A), including stereochemically isomeric forms, and salts, hydrates, solvates thereof, wherein Ra to Rd, and R1 to R8 have the meaning as defined herein. The present invention also relates to processes for preparing said compounds, pharmaceutical compositions containing them and their use, alone or in combination with other HBV inhibitors, in HBV therapy.
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Page/Page column 171; 172
(2017/01/23)
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- TYK2 INHIBITORS AND USES THEREOF
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The present invention provides compounds, compositions thereof, and methods of using the same for the inhibition of TYK2, and the treatment of TYK2-mediated disorders.
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Paragraph 0412; 0413; 0414
(2016/09/26)
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- A convenient method for the enantiomeric separation of α-amino acid esters as benzophenone imine schiff base derivatives
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A convenient liquid chromatographic method for the separation of α-amino acid esters as benzophenone Schiff base derivatives on coated chiral stationary phases (CSPs) (Chiralcel OD-H, Chiralcel OD, Chiralpak AD-H, Chiralpak AD, and Chiralpak AS) or covalently immobilized CSPs (Chiralpak IA, Chiralpak IB, and Chiralpak IC) derived from polysaccharide derivatives is described. Benzophenone imine derivatives of α-amino acid esters were readily prepared by stirring benzophenone imine and the hydrochloride salts of α-amino acid esters in 2-propanol. The chromatographic separations were conducted at a flow rate 1.0 mL/min and a detection wavelength of 254 nm; 0.5% 2-propanol/hexane (v/v) was used on CSPs. In general, the resolution of Chiralpak IC was superior to those of the other CSPs. In addition, the resolutions of other arylimine derivatives of α-amino acid esters and the effects of different mobile phases on the enantiomeric separation of α-amino acid esters as benzophenone imine derivatives on Chiralpak IC were investigated.
- Huang, Hu,Xu, Wen Jun,Jin, Jing-Yu,Hong, Joon Hee,Shin, Hyun-Jae,Lee, Wonjae
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experimental part
p. 1015 - 1019
(2012/10/08)
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- Monofluorinated aziridines in asymmetric synthesis of chiral fluorinated prop-2-yn-1-amines
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Nonracemic C-fluoroaziridines were synthesized for the first time by reaction of fluorocarbene with N-diphenylmethylidene-substituted natural amino acid esters. The products were shown to be used in asymmetric synthesis of chiral fluorinated prop-2-yn-1-amines via one-pot process involving isomerization of 2-fluoroaziridines into α-fluoro imines and subsequent reaction with alkynyldifluoroborane generated in situ.
- Konev,Abbaspour Tehrani,Khlebnikov,Novikov,Magull
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scheme or table
p. 976 - 986
(2010/10/21)
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- Rhodium-catalyzed asymmetric hydrogenation through dynamic kinetic resolution: asymmetric synthesis of anti-β-hydroxy-α-amino acid esters
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Rhodium-catalyzed asymmetric hydrogenation of α-amino-β-keto ester hydrochlorides through dynamic kinetic resolution is described. The hydrogenation proceeds with the catalyst derived from a Rh complex and a chiral ferrocenylphosphine under hydrogen in th
- Makino, Kazuishi,Fujii, Takefumi,Hamada, Yasumasa
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p. 481 - 485
(2007/10/03)
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- 2, 4, 6-SUBSTITUTED PYRIDYL DERIVATIVE COMPOUNDS USEFUL AS BETA-SECRETASE INHIBITORS FOR THE TREATMENT OF ALZHEIMER’S DISEASE
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The present invention is directed to 2, 4, 6-substituted pyridyl derivative compounds which are inhibitors of the beta-secretase enzyme and that are useful in the treatment of diseases in which the beta-secretase enzyme is involved, such as Alzheimer’s disease. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the treatment of such diseases in which the beta-secretase enzyme is involved.
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Page/Page column 46
(2010/02/14)
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- Reaction of dihalocarbenes with N-Alkylidene amino acid esters and nitriles. Synthesis of aziridine and pyrrole amino acid derivatives
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Conditions for preparation of functionalized geminal dihaloaziridines by reaction of dihalocarbenes with N-benzhydrylidene amino acid esters and nitriles were found. The direction of transformations of the intermediate azomethine ylides depends on the structure of the latter, as deduced from MNDO calculations.
- Khlebnikov,Novikov,Nikiforova,Kostikov
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- ENANTIOSELECTIVE METHYLATION OF GLYCINE INFLUENCE OF THE STRUCTURE OF THE CHIRAL NUCLEOFUGAL
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Variation of the enantioselection from e.e.= 0 to 76percent was observed in the enantioface differentiation of the prochiral enolates 2a and 2b by a serie of mixed sulfates derived from D-(+)-glucose.
- Duhamel, Pierre,Eddine, Jamal Jamal,Valnot, Jean-Yves
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p. 3801 - 3804
(2007/10/02)
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