#E-/Z_ notation

Cis-trans and E-Z notation: choose your side

10 Comments / Drug stereochemistry / By Valliappan Kannappan / #cis-trans, #E-/Z_ notation, #geometrical _isomers, #naming_system

“Pharmacological studies confirm the high activity of triprolidine and the superiority of (E) over corresponding (Z) isomers as H, antagonist” ( Ref: – – – from “Wilson and Gisvold’s Textbook of organic medicinal and pharmaceutical chemistry, 2010”). “Triprolidine is 2-[(E)-1-(4-methylphenyl)-3-pyrrolidin-1-ylprop-1-enyl]pyridine”, the IUPAC name. To understand the above statements one need to be familiar with the “cis-trans and E-/Z- nomenclature. How to translate the name to structure and vice versa? This blog is basically to discuss …

Cis-trans and E-Z notation: choose your side Read More »

Atropisomers: things are tight, single bond won’t rotate

3 Comments / Chirality / By Valliappan Kannappan / #axial_chirality, #CIP_rule, #E-/Z_ notation, #naming_system

Atropisomers are stereoisomers resulting from hindered rotation about single bonds where the steric strain barrier to rotation is high enough to allow for the separation of the conformers. Note: Butane, for example, has conformations that are atropisomers; however, unlike the biaryls, the barrier to rotation is so small that they are interconverted rapidly at room temperature, and they are, for practical purposes, achiral. As a general rule of thumb, chiral molecules must have at least …

Atropisomers: things are tight, single bond won’t rotate Read More »