Substituted benzamides with conformationally restricted side chains. 2. Indolizidine derivatives as central dopamine receptor antagonists
摘要:
The substituted benzamides metoclopramide (1) and clebopride (3) are stimulants of gastric motility. They are also central dopamine receptor antagonists with 3 being the more potent. This is presumed to be due to an additional interaction of its N-benzyl group with the receptor. The effect of restricting the conformation of this group by replacing the N-benzylpiperidine side chain of 3 by phenyl-substituted quinolizidines and indolizidines has been investigated. Only the indolizidines had significant activity, the nature of which depended upon the orientation of the phenyl substituent. The 2 alpha-phenyl isomers 5d-h were potent central dopamine D2 receptor antagonists with 5h showing selectivity for the limbic system. The 2 beta-phenyl isomer 5c was a gastric motility stimulant devoid of significant central dopamine receptor antagonist activity. Implications on receptor models are discussed.
Chiral Brønsted Acid Catalyzed Dynamic Kinetic Asymmetric Hydroamination of Racemic Allenes and Asymmetric Hydroamination of Dienes
作者:Jin‐Shun Lin、Tao‐Tao Li、Guan‐Yuan Jiao、Qiang‐Shuai Gu、Jiang‐Tao Cheng、Ling Lv、Xin‐Yuan Liu
DOI:10.1002/anie.201900955
日期:2019.5.20
The first highly efficient and practical chiral Brønsted acid catalyzed dynamic kinetic asymmetric hydroamination (DyKAH) of racemic allenes and asymmetric hydroamination of unactivated dienes with both high E/Z selectivity and enantioselectivity are described herein. The transformation proceeds through a new catalytic asymmetric model involving a highly reactive π‐allylic carbocationic intermediate