描述了作为活化氨基酸衍生物的氮杂内酯的第一次催化不对称共轭加成反应向烯酮的发展和进一步发展。第一代方法是从孤立的氮杂内酯开始的,而第二代方法中的氮杂内酯可以从外消旋的N开始原位生成。苯甲酰化氨基酸。第三个进化阶段可以利用外消旋未保护的α-氨基酸直接形成高度对映体富集和非对映体纯的带掩蔽季铵氨基酸产物,并带有一个附加的叔立体中心。通过使用稳固的平面手性bis-Pd催化剂,布朗斯台德酸(HOAc或BzOH; Ac =乙酰基,Bz =苯甲酰基)和布朗斯台德碱(NaOAc),通过协同活化来实现逐步经济转型。特别是第二代和第三代方法提供了快速而多样化的途径,可从廉价的散装化学品中获得生物学上令人感兴趣的非天然季氨基酸衍生物。这样,可以以非对映体纯形式制备高度对映体富集的无环α-氨基酸,α-烷基脯氨酸和α-烷基焦谷氨酸衍生物。此外,
A step-economic and one-pot access to chiral C<sup>α</sup>-tetrasubstituted α-amino acid derivatives <i>via</i> a bicyclic imidazole-catalyzed direct enantioselective <i>C</i>-acylation
Cα-Tetrasubstituted α-amino acids are ubiquitous and unique structural units in bioactive natural products and pharmaceutical compounds. The asymmetric synthesis of these molecules has attracted a lot of attention, but a more efficient method is still greatly desired. Here we describe the first sequential four-step acylation reaction for the efficientsynthesis of chiral Cα-tetrasubstituted α-amino acid derivatives
Group-Assisted Purification Chemistry for Asymmetric Mannich-type Reaction of Chiral <i>N</i>-Phosphonyl Imines with Azlactones Leading to Syntheses of α-Quaternary α,β-Diamino Acid Derivatives
作者:Haowei Zhang、Zhen Yang、Brian Nlong Zhao、Guigen Li
DOI:10.1021/acs.joc.7b02556
日期:2018.1.19
An asymmetric Mannich-type reaction between chiral N-phosphonyl imines and azlactones [oxazol-5(4H)-ones] has been established under convenient conditions at room temperature. The reaction was performed without using any bases, additives, or catalysts to achieve up to excellent chemical yields and diastereoselectivity for 32 examples. The α-quaternary syn-α,β-diamino acid products were purified simply
Compounds of formula I:
are useful in treating diseases prevented by or ameliorated with potassium channel openers. Also disclosed are potassium channel opening compositions and a method of opening potassium channels in a mammal.
Metal-Free Insertion Reactions of Diazo Carbonyls to Azlactones
作者:Amanda C. de Mello、Patrícia B. Momo、Antonio C. B. Burtoloso、Giovanni W. Amarante
DOI:10.1021/acs.joc.8b01683
日期:2018.9.21
Insertionreactions of diazo carbonyls to azlactones in basic conditions have been performed. The developed method allows the preparation of a wide range of oxazole derivatives in yields ranging from 74 to 98%. Different substituents on both azlactone rings and diazo carbonyls do not compromise the methodology, even those containing stereogenic centers. Isotopic labeling experiments revealed the mechanism
Indane acetic acid derivatives and their use as pharmaceutical agents, intermediates, and method of preparation
申请人:——
公开号:US20030216391A1
公开(公告)日:2003-11-20
This invention relates to novel indane acetic acid derivatives which are useful in the treatment of diseases such as diabetes, obesity, hyperlipidemia, and atherosclerotic diseases. The invention also relates to intermediates useful in preparation of indane acetic derivatives and to methods of preparation.