- N-transfer reagent and method for preparing the same and its application
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Provided are a novel N-transfer reagent and a method for preparing the same and its application. The N-transfer reagent is represented by the following Formula (I): The various novel N-transfer reagents of the present invention can be quickly prepared by employing different nitrobenzene precursors. The N-transfer reagents can directly convert a variety of amino compounds into diazo compounds under mild conditions. Particularly, the N-transfer reagents can facilitate the synthesis of the diazo compounds. The application of synthesizing diazo compounds of the present invention can greatly decrease the difficulty in operation, increase the safety during experiments, reduce the cost of production and the environmental pollution, and enhance the industrial value of diazo compounds.
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Page/Page column 25; 49-50; 55-56
(2021/06/25)
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- NovelN-transfer reagent for converting α-amino acid derivatives to α-diazo compounds
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A novel universalN-transfer reagent for direct and effective transformation of α-amino ketones, acetamides, and esters to the corresponding α-diazo products under mild basic conditions has been developed. This one-step synthetic approach not only allows for generation of α-substituted-α-diazo carbonyl compounds from α-amino acid derivatives but also permits preparation of α-diazo dipeptides fromN-terminal dipeptides (32 examples, up to 91%).
- Lu, Guan-Han,Huang, Tzu-Chia,Hsueh, Hsiao-Chin,Yang, Shin-Cherng,Cho, Ting-Wei,Chou, Ho-Hsuan
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supporting information
p. 4839 - 4842
(2021/05/25)
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- Rhodium-Catalyzed Enantioselective Synthesis of Oxazinones via an Asymmetric Ring Opening-Lactonization Cascade of Oxabicyclic Alkenes
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The rhodium-catalyzed asymmetric ring opening reaction of oxabicyclic alkenes is shown to be an efficient method for synthesizing chiral heterocycles. We demonstrate that the pairwise combination of chiral catalyst with chiral amino-acid-derived pronucleophiles results in a stereodivergent synthesis of diastereomeric hydroxyesters. A favorable conformational preference induces the subsequent lactonization of one diastereomer leading to the highly enantioselective synthesis of oxazinones.
- Yen, Andy,Pham, Anh Hoang,Larin, Egor M.,Lautens, Mark
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supporting information
p. 7549 - 7553
(2019/10/02)
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- A new type of chiral-pyridoxamines for catalytic asymmetric transamination of α-keto acids
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A new type of chiral pyridoxamines bearing an adjacent chiral stereocenter has been developed via multi-step synthesis. The pyridoxamines displayed catalytic activity in asymmetric transamination of α-keto acids to give a variety of optically active amino acids in 27–78% yields with 34–62% ee's under very mild conditions. This work provides a synthetic strategy to construct new chiral pyridoxamines using bromopyridine 7 as a key synthon and also represents an early example of the applications of chiral pyridoxamines in asymmetric catalysis.
- Chen, Jianfeng,Zhao, Junyu,Gong, Xing,Xu, Dongfang,Zhao, Baoguo
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supporting information
p. 4612 - 4615
(2016/09/23)
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- A diastereoselective construction of pyrazinoisoquinoline skeletons via tandem cyclization of phenylalanine derivatives: A facile synthesis of optically active pyrazinoisoquinolines
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A facile and stereocontrolled construction of optically active pyrazinoisoquinoline skeletons based on tandem cyclization of enantiopure phenylalanine derivatives was examined. The reaction provided optically active 6,11b-trans pyrazinoisoquinoline ring systems in excellent diastereoselectivity, and this method was applicable to the cyclization of phenylalanine derivatives with diverse substituents.
- Seki, Maki,Ogiku, Tsuyoshi
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p. 3864 - 3870
(2014/06/09)
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- Asymmetric chemoenzymatic synthesis of N-acetyl-α-amino esters based on lipase-catalyzed kinetic resolutions through interesterification reactions
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Several phenylalanine analogs have been synthesized through a four-step route starting from easily available ethyl acetamidocyanoacetate. In a first reaction, and making use of phase transfer catalysts, this compound reacted with several alkyl halides, being benzyltributylammonium chloride identified as the best one for the production of a series of quaternary amino acids in moderate to excellent yields (52-95%). Then, the corresponding N-acetyl-phenylalanine methyl and allyl ester derivatives were obtained through acidic hydrolysis, esterification, and N-acetylation. Rhizomucor miehei lipase was found as a versatile enzyme for the resolution of these amino esters, finding the best results through interesterification reactions with butyl butyrate in acetonitrile. A great influence in the stereoselectivity was found depending on the chemical structure of the compound, achieving for the non- or para-substituted in the phenyl ring excellent stereoselectivities, being moderate for the meta-nitro derivative, while the ortho-nitro amino ester did not react.
- Da Silva, Marcos Reinaldo,De Mattos, Marcos Carlos,De Oliveira, Maria Da Concei??o Ferreira,De Lemos, Telma Leda Gomes,Ricardo, Nágila Maria Pontes Silva,De Gonzalo, Gonzalo,Lavandera, Iván,Gotor-Fernández, Vicente,Gotor, Vicente
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p. 2264 - 2271
(2014/03/21)
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- Synthesis and bioactivity of novel 3-(1-hydroxyethylidene)-5-substituted- pyrrolidine-2,4-dione derivatives
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Ten novel 5-substituted derivatives of 3-(1-hydroxyethylidene)pyrrolidine- 2,4-dione were synthesized. The compounds were confirmed by IR, 1H NMR, MS and elemental analysis. The bioassay indicated that these compounds showed noticeable herbicid
- Han, Bao Feng,Shi, Qing Ming,Wang, Xian Feng,Liu, Jian Bo,Qiang, Sheng,Yang, Chun Long
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p. 1023 - 1026
(2012/10/08)
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- Oleanolic acid and its derivatives: New inhibitor of protein tyrosine phosphatase 1B with cellular activities
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Protein tyrosine phosphatase 1B is a key factor in the negative regulation of insulin pathway and a promising target for treatment of diabetes and obesity. Herein, a series of competitive inhibitors were optimized from oleanolic acid, a natural triterpenoid identified against PTP1B by screening libraries of traditional Chinese medicinal herbs. Modifying at 3 and 28 positions, we obtained compound 13 with a Ki of 130 nM, which exhibited good selectivity between other phosphatases involved in insulin pathway except T-cell protein tyrosine phosphatase. Further evaluation in cell models illustrated that the derivatives enhanced insulin receptor phosphorylation in CHO/hIR cells and also stimulated glucose uptake in L6 myotubes with or addition of without insulin.
- Zhang, Yi-Nan,Zhang, Wei,Hong, Di,Shi, Lei,Shen, Qiang,Li, Jing-Ya,Li, Jia,Hu, Li-Hong
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p. 8697 - 8705
(2008/12/23)
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- Octapeptides and methods for their production
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New octapeptides having the formula Prot Grp-R-Trp-Ser-Tyr-R2 -Leu-Arg-Pro-R3 ; salts thereof; wherein R is Gln, Gln (bzl), His (bzl), Ser (bzl), Pro, Leu, Tyr (bzl), Ile, Cys (bzl) or Phe, R2 is D-Phe, D-Ala, D-Leu, D-Trp, D-Tyr, D-Tyr (Me), D-Ser, D-Met, D-Arg, D-Val, D-His, D-Gln, D-Phs, D-Thr, D-Pro, D-Me5 Phe or D-Asn and R3 is NH2, NH(lower alkyl), N-(lower alkyl)2, NH-benzyl, NHCH2 CH2 N-(lower alkyl)2 or NH-CH2 CH2 SO2 NH-benzyl; methods for their production; certain peptide intermediates and their salts used in the production thereof; and the use of said octapeptides as luteinizing hormone releasing factor antagonists.
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