一些含有两个立体中心的新型酰胺的对映体衍生自D-和L -α-氨基酸作为客体,通过1 H NMR 光谱进行手性识别。催化不对称合成产物、天然产物或其全合成产物、手性药物中常存在多种具有两个或多个立体中心的手性酰胺。探索它们的手性识别将是一项具有挑战性且有意义的工作。为此,由(1 S ,2 S )-(+)-1,2-二氨基环己烷、 D -α-氨基酸和异硫氰酸酯作为手性溶剂合成了一类新型手性双硫脲衍生物1-9 (国家安全局)。事实证明,CSAs 1-9对大多数具有两个立构中心的酰胺具有更好的手性辨别结果,而这些酰胺很少作为手性底物通过1 H NMR 光谱进行研究。特别是,具有 3,5-双(三氟甲基)苯残基的 CSA 7 、 8和9 ,对所有酰胺表现出出色的手性辨别能力,提供良好分离的1 H NMR 信号和足够大的非等价化学位移。为了测试它们在测定对映体过量方面的实际应用,分别在 CSA 7和8存在下测量了不同光学纯度的手性酰胺
Liquid Chromatographic Resolution of Tocainide and Its Analogues on a Doubly Tethered Chiral Stationary Phase Based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic Acid
作者:Hee-Jin Kim、Hee-Jung Choi、Myung-Ho Hyun
DOI:10.5012/bkcs.2010.31.03.678
日期:2010.3.20
A doubly tethered chiralstationaryphase (CSP) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylicacid were appli- ed to the liquidchromatographic resolution of racemic tocainide, an antiarrhythmic agent, and its analogues. The chiral recognition efficiency of the doubly tethered CSP for tocainide and its analogues was generally greater than that of the corresponding singly tethered CSP especially
An unprecedented Ru-catalyzed directasymmetric reductive amination of α-keto amides with ammonium salts has been achieved. This protocol provides an efficient and practical way for the synthesis of diverse enantioenriched α-aryl- or alkyl-substituted N-unprotected unnatural α-amino acids and N-unprotected β-branched α-amino acids. Further follow-up transformations enable access to drug intermediates