The isomer‐pairs of the 2‐arylamino‐2‐thiazolines and ‐thiazines, carrying a methyl substituent on the nitrogen atom of the ring and outside the ring were synthesised by unambiguous routes. An IR and NMR investigation of these compounds revealed the fact that the NMR signal of the 2,6‐symmetrically substituted aryl group can be used advantageously for the determination of the isomeric structures. The AB2 multiplet of the aromatic protons is shifted towards the AX2 pattern in the b isomer—containing a conjugated CN bond outside the ring—as compared to the a isomers. The structure of this multiplet does not depend on the size of the hetero‐ring.
ASJC Scopus subject areas
- Materials Science(all)