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 scope of the method, including various sensitive functional groups, late-stage modification and the synthesis of drug molecules (>80 examples). Remarkable selectivity towards different functional groups and within different amide and ester electrophiles
酰胺键是化学和生物学中最基本的官能团之一,在许多简化关键药物和工业分子合成的过程中发挥着核心作用。尽管酰胺的合成是学术和工业科学家最常进行的反应之一,但由于该过程不利的动力学和热力学贡献,叔酰胺的直接转酰胺具有挑战性。在此,我们报告了第一种通用的、温和的和高度化学选择性的方法,用于通过非亲核胺的直接酰基 NC 键裂解对未活化的叔酰胺进行转酰胺。这种操作简单的方法是在没有过渡金属的情况下进行的,并且在异常温和的反应条件下进行。在这种情况下,我们进一步描述了大量烷基酯的直接酰胺化,以通过酰基 CO 键裂解提供具有极好的选择性的酰胺键。该方法的广泛应用展示了该过程的实用性,包括各种敏感的官能团、后期修饰和药物分子的合成(> 80 个例子)。观察到对不同官能团以及不同酰胺和酯亲电试剂的显着选择性,这是使用现有方法不可行的。进行了广泛的实验和计算研究,以深入了解高选择性的机制和起源。我们进一步提出了
Conversion of amides to esters by the nickel-catalysed activation of amide C–N bonds
作者:Liana Hie、Noah F. Fine Nathel、Tejas K. Shah、Emma L. Baker、Xin Hong、Yun-Fang Yang、Peng Liu、K. N. Houk、Neil K. Garg
DOI:10.1038/nature14615
日期:2015.8
Although enzymes are able to cleave amide bonds in nature, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry; now the activation and cleavage of these bonds using nickel catalysts is used to convert amides to esters. Although enzymes are able to cleave amide bonds in nature, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry. In this paper the authors demonstrate that amide CâN bonds can be activated and cleaved using nickel catalysts. They used this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. Amides are common functional groups that have been studied for more than a century1. They are the key building blocks of proteins and are present in a broad range of other natural and synthetic compounds. Amides are known to be poor electrophiles, which is typically attributed to the resonance stability of the amide bond1,2. Although amides can readily be cleaved by enzymes such as proteases3, it is difficult to selectively break the carbonânitrogen bond of an amide using synthetic chemistry. Here we demonstrate that amide carbonânitrogen bonds can be activated and cleaved using nickel catalysts. We use this methodology to convert amides to esters, which is a challenging and underdeveloped transformation. The reaction methodology proceeds under exceptionally mild reaction conditions, and avoids the use of a large excess of an alcohol nucleophile. Density functional theory calculations provide insight into the thermodynamics and catalytic cycle of the amide-to-ester transformation. Our results provide a way to harness amide functional groups as synthetic building blocks and are expected to lead to the further use of amides in the construction of carbonâheteroatom or carbonâcarbon bonds using non-precious-metal catalysis.
[EN] 5-LIPOXYGENASE INHIBITORS<br/>[FR] INHIBITEURS DE 5-LIPOXYGÉNASE
申请人:RANBAXY LAB LTD
公开号:WO2012014127A1
公开(公告)日:2012-02-02
The present invention relates to sulfonamides derivatives as 5-lipoxygenase (5-LO) inhibitors and a process for their synthesis. The present invention also relates to pharmacological compositions containing these sulfonamides derivatives, as well as methods of treating bronchial asthma, chronic obstructive pulmonary disease, rheumatoid arthritis, multiple sclerosis, Type I diabetes, psoriasis, allograft rejection, inflammatory bowel disease, ulcerative colitis, acne, atherosclerosis, cancer, pruritis, allergic rhinitis and other inflammatory and/or autoimmune disorders.
Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
作者:Zhao Li、Chenjun Guo、Jue Chen、Yingming Yao、Yunjie Luo
DOI:10.1002/aoc.5517
日期:2020.4
The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe3)2]3(μ‐Cl)Li (THF)3 as the catalysts, it was found a broad