Bis[oxo/thioxothiazolinyl] Aromatic Compounds - Synthesis and Conformational Assignment

Abstract

A series of bis(oxo/thioxothiazolinyl) aromatic atropisomers with two chiral C(aryl)‐N(heterocycle) axes was synthesized. The separation of antiparallel, parallel diastereomers was achieved by chromatography on silica. Conformational assignment for the bis‐thione atropisomers 1a,b‐4a,b and bis‐one atropisomers 9a,b‐12a,b was based on polarimetric results in analytical chiral chromatography on microcrystalline cellulose triacetate. The relationship conformation‐1H NMR chemical shifts, found for the bis‐thiones and bis‐ones was successfully applied for the conformational assignment of thione‐one atropisomers not assigned by chiral liquid chromatography.