The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
Yoshihisa Kobayashi - One of the best experts on this subject based on the ideXlab platform.
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Facile Procedure for Generating Side Chain Functionalized Poly(α-hydroxy acid) Copolymers from Aldehydes via a Versatile Passerini-Type Condensation
Organic Letters, 2010Co-Authors: Mark Rubinshtein, Yoshihisa Kobayashi, Carrie R. James, Jennifer L. Young, Yanyan J., Nathan C. Gianneschi, Jerry YangAbstract:A general method for synthesizing α-hydroxy N-Acylindoles in one-pot via an acid-catalyzed condensation of a convertible isonitrile with water and various aldehydes is presented. These intermediates were incorporated into poly(α-hydroxy acid) copolymers bearing residues with functionalizable side chains, which could be further modified through Cu(I)-catalyzed azide−alkyne cylcoaddition reactions. This versatile synthetic strategy provides access to side chain functionalized poly(α-hydroxy acid) copolymers from readily available aldehydes, making it potentially useful as an approach to synthesize biodegradable polymers with new, tunable properties.
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Synthesis of functionalized pyroglutamic acids, part 1: The synthetic utility of N-Acylindole and the ugi reaction with a chiral levulinic acid
Synlett, 2008Co-Authors: Matthew J. Buller, Cynthia B. Gilley, Brian J. Nguyen, Lisa Olshansky, Breena Fraga, Yoshihisa KobayashiAbstract:A variety of pyroglutamic acid derivatives are readily synthesized via N-Acylindole intermediates obtained by the Ugi reaction. For the preparation of functionalized pyroglutamic acid derivatives, the diastereoselectivity of the Ugi 4-center 3-component condensation reaction with a chiral γ-keto acid and convertible isocyanide is described.
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New entry to convertible isocyanides for the Ugi reaction and its application to the stereocontrolled formal total synthesis of the proteasome inhibitor omuralide.
Organic Letters, 2007Co-Authors: Cynthia B. Gilley, Matthew J. Buller, Yoshihisa KobayashiAbstract:The development of a new convertible isocyanide, indole-isocyanide, for ready access to pyroglutamic acids culminated in the formal total synthesis of the proteasome inhibitor omuralide featuring a stereocontrolled Ugi reaction. Indole-isocyanide was named after the facilitation of hydrolysis of the resulting 2-(2,2-dimethoxyethyl)anilide via an N-Acylindole intermediate obtained by the Ugi multicomponent condensation reaction followed by the indole formation.
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Synthesis of Bicyclic Pyroglutamic Acid Featuring the Ugi Reaction and a Unique Stereoisomerization at the Angular Position by Grob Fragmentation Followed by a Transannular Ketene [2+2] Cycloaddition Reaction
Synlett, 2007Co-Authors: Mitchell Vamos, Kerem E. Ozboya, Yoshihisa KobayashiAbstract:A stereoisomerization at the angular position of N-Acylindoles during basic hydrolysis was discovered to give only the syn-bicyclic pyroglutamic acid, proceeding through a transannular [2+2] cycloaddition of a ketene-ketone intermediate generated by a Grob fragmentation.
Franz Bracher - One of the best experts on this subject based on the ideXlab platform.
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a new approach to 1 substituted β carbolines and isoquinolines utilizing tributyl z 2 ethoxyvinyl stannane as a c 3 c 4 building block
Tetrahedron, 2016Co-Authors: Alexandra Kamlah, Florian Lirk, Franz BracherAbstract:Abstract Starting from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substituted isoquinolines are available in an analogous manner starting from 2-bromobenzoic acid.
Juan Feng - One of the best experts on this subject based on the ideXlab platform.
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Collective Synthesis of 3-Acylindoles, Indole-3-carboxylic Esters, Indole-3-sulfinic Acids, and 3-(Methylsulfonyl)indoles from Free (N–H) Indoles via Common N-Indolyl Triethylborate
Organic Letters, 2016Co-Authors: Zhi Wei Zhang, Hailing Li, Huaiping Kang, Juan FengAbstract:A general and direct C3 functionalization of free (N–H) indoles with readily available electrophiles such as acid chlorides, chloroformates, thionyl chloride, and methylsulfonyl chloride via a common N-indolyl triethylborate intermediate is reported. The reaction proceeds smoothly under mild conditions in up to 93% yield. Indoles with substituents at the C2, C4, C5, C6, and C7 positions are well tolerated. The easy accessibility of a variety of important 3-acylindoles, indole-3-carboxylic esters, indole-3-sulfinic acids, and 3-(methylsulfonyl)indoles demonstrates the high degree of compatibility and practicability of this method.
Matthew J. Buller - One of the best experts on this subject based on the ideXlab platform.
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Synthesis of functionalized pyroglutamic acids, part 1: The synthetic utility of N-Acylindole and the ugi reaction with a chiral levulinic acid
Synlett, 2008Co-Authors: Matthew J. Buller, Cynthia B. Gilley, Brian J. Nguyen, Lisa Olshansky, Breena Fraga, Yoshihisa KobayashiAbstract:A variety of pyroglutamic acid derivatives are readily synthesized via N-Acylindole intermediates obtained by the Ugi reaction. For the preparation of functionalized pyroglutamic acid derivatives, the diastereoselectivity of the Ugi 4-center 3-component condensation reaction with a chiral γ-keto acid and convertible isocyanide is described.
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New entry to convertible isocyanides for the Ugi reaction and its application to the stereocontrolled formal total synthesis of the proteasome inhibitor omuralide.
Organic Letters, 2007Co-Authors: Cynthia B. Gilley, Matthew J. Buller, Yoshihisa KobayashiAbstract:The development of a new convertible isocyanide, indole-isocyanide, for ready access to pyroglutamic acids culminated in the formal total synthesis of the proteasome inhibitor omuralide featuring a stereocontrolled Ugi reaction. Indole-isocyanide was named after the facilitation of hydrolysis of the resulting 2-(2,2-dimethoxyethyl)anilide via an N-Acylindole intermediate obtained by the Ugi multicomponent condensation reaction followed by the indole formation.
Alexandra Kamlah - One of the best experts on this subject based on the ideXlab platform.
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a new approach to 1 substituted β carbolines and isoquinolines utilizing tributyl z 2 ethoxyvinyl stannane as a c 3 c 4 building block
Tetrahedron, 2016Co-Authors: Alexandra Kamlah, Florian Lirk, Franz BracherAbstract:Abstract Starting from readily available indole-2-carboxylic acids, 1-substituted β-carbolines (among them the alkaloids harmane and isoharmine) are readily obtained via the corresponding 2-acylindoles, bromination at C-3, followed by a one-pot Stille cross-coupling with tributyl[(Z)-2-ethoxyvinyl]stannane, and ring closure with ammonium acetate. 1-Substituted isoquinolines are available in an analogous manner starting from 2-bromobenzoic acid.
