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Amides

The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Michal Szostak – 1st expert on this subject based on the ideXlab platform

  • metal free transamidation of secondary Amides by n c cleavage
    Journal of Organic Chemistry, 2019
    Co-Authors: Md Mahbubur Rahman, Guangchen Li, Michal Szostak

    Abstract:

    Transamidation reactions represent a fundamental chemical process involving conversion of one amide functional group into another. Herein, we report a facile, highly chemoselective method for transamidation of N-tert-butoxycarbonylation (N-Boc) activated secondary Amides that proceeds under exceedingly mild conditions in the absence of any additives. Because this reaction is performed in the absence of metals, oxidants, or reductants, the reaction tolerates a large number of useful functionalities. The reaction is compatible with diverse Amides and nucleophilic amines, affording the transamidation products in excellent yields through direct nucleophilic addition to the amide bond. The utility of this methodology is highlighted in the synthesis of Tigan, a commercial antiemetic, directly from the amide bond. We expect that this new metal-free transamidation will have broad implications for the development of new transformations involving direct nucleophilic addition to the amide bond as a key step.

  • highly chemoselective transition metal free transamidation of unactivated Amides and direct amidation of alkyl esters by n c o c cleavage
    Journal of the American Chemical Society, 2019
    Co-Authors: Guangchen Li, Michal Szostak, Chonglei Ji, Xin Hong

    Abstract:

    The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of Amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary Amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary Amides by a direct acyl N–C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C–O bond cleavage. The utility of this process is showcased by a broad sc…

  • highly selective transition metal free transamidation of Amides and amidation of esters at room temperature
    Nature Communications, 2018
    Co-Authors: Guangchen Li, Michal Szostak

    Abstract:

    Amide chemistry has an essential role in the synthesis of high value molecules, such as pharmaceuticals, natural products, and fine chemicals. Over the past years, several examples of transamidation reactions have been reported. In general, transition-metal-based catalysts or harsh conditions are employed for these transformations due to unfavorable kinetics and thermodynamics of the process. Herein, we report a significant advance in this area and present the general method for transition-metal-free transamidation of Amides and amidation of esters by highly selective acyl cleavage with non-nucleophilic amines at room temperature. In contrast to metal-catalyzed protocols, the method is operationally-simple, environmentally-friendly, and operates under exceedingly mild conditions. The practical value is highlighted by the synthesis of valuable Amides in high yields. Considering the key role of Amides in various branches of chemical science, we envision that this broadly applicable method will be of great interest in organic synthesis, drug discovery, and biochemistry.

Guangchen Li – 2nd expert on this subject based on the ideXlab platform

  • metal free transamidation of secondary Amides by n c cleavage
    Journal of Organic Chemistry, 2019
    Co-Authors: Md Mahbubur Rahman, Guangchen Li, Michal Szostak

    Abstract:

    Transamidation reactions represent a fundamental chemical process involving conversion of one amide functional group into another. Herein, we report a facile, highly chemoselective method for transamidation of N-tert-butoxycarbonylation (N-Boc) activated secondary Amides that proceeds under exceedingly mild conditions in the absence of any additives. Because this reaction is performed in the absence of metals, oxidants, or reductants, the reaction tolerates a large number of useful functionalities. The reaction is compatible with diverse Amides and nucleophilic amines, affording the transamidation products in excellent yields through direct nucleophilic addition to the amide bond. The utility of this methodology is highlighted in the synthesis of Tigan, a commercial antiemetic, directly from the amide bond. We expect that this new metal-free transamidation will have broad implications for the development of new transformations involving direct nucleophilic addition to the amide bond as a key step.

  • highly chemoselective transition metal free transamidation of unactivated Amides and direct amidation of alkyl esters by n c o c cleavage
    Journal of the American Chemical Society, 2019
    Co-Authors: Guangchen Li, Michal Szostak, Chonglei Ji, Xin Hong

    Abstract:

    The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of Amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary Amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary Amides by a direct acyl N–C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C–O bond cleavage. The utility of this process is showcased by a broad sc…

  • highly selective transition metal free transamidation of Amides and amidation of esters at room temperature
    Nature Communications, 2018
    Co-Authors: Guangchen Li, Michal Szostak

    Abstract:

    Amide chemistry has an essential role in the synthesis of high value molecules, such as pharmaceuticals, natural products, and fine chemicals. Over the past years, several examples of transamidation reactions have been reported. In general, transition-metal-based catalysts or harsh conditions are employed for these transformations due to unfavorable kinetics and thermodynamics of the process. Herein, we report a significant advance in this area and present the general method for transition-metal-free transamidation of Amides and amidation of esters by highly selective acyl cleavage with non-nucleophilic amines at room temperature. In contrast to metal-catalyzed protocols, the method is operationally-simple, environmentally-friendly, and operates under exceedingly mild conditions. The practical value is highlighted by the synthesis of valuable Amides in high yields. Considering the key role of Amides in various branches of chemical science, we envision that this broadly applicable method will be of great interest in organic synthesis, drug discovery, and biochemistry.

David Milstein – 3rd expert on this subject based on the ideXlab platform

  • direct hydrogenation of Amides to alcohols and amines under mild conditions
    ChemInform, 2011
    Co-Authors: Ekambaram Balaraman, Boopathy Gnanaprakasam, Linda J W Shimon, David Milstein

    Abstract:

    Amides can be selectively and directly hydrogenated to alcohols and amines for the first time.

  • direct hydrogenation of Amides to alcohols and amines under mild conditions
    Journal of the American Chemical Society, 2010
    Co-Authors: Ekambaram Balaraman, Boopathy Gnanaprakasam, Linda J W Shimon, David Milstein

    Abstract:

    The selective, direct hydrogenation of Amides to the corresponding alcohols and amines with cleavage of the C−N bond was discovered. The expected products of C−O cleavage are not formed (except as traces in the case of anilides). The reaction proceeds under mild pressure and neutral, homogeneous conditions using a dearomatized, bipyridyl-based PNN Ru(II) pincer complex as a catalyst. The postulated mechanism involves metal−ligand cooperation by aromatization−dearomatization of the heteroaromatic pincer core and does not involve hydrolytic cleavage of the amide. The simplicity, generality, and efficiency of this environmentally benign process make it attractive for the direct transformations of Amides to alcohols and amines in good to excellent yields.