Stable hemiaminals from axially chiral pyridine compounds

In this study, we have synthesized a series of 3-(pyridin-2-yl)-2-(pyridin-2-ylimino)thiazolidin-4-ol derivatives regioselectively from 2-iminothiazolidin-4-ones using LiAlH4 at room temperature. Due to the presence of the restricted rotation around the N3-C-aryl single bond, the formation of M/P isomers was observed. The OH group of the hemiaminal was found to orient itself on the same side with pyridyl nitrogen during this restricted rotation to form an intramolecular hydrogen bond, which was demonstrated by the computational DFT study. This orientation presumably inhibited the occurrence of dehydration and stabilized the molecule.

Automated summary

In this study, a series of 3-(pyridin-2-yl)-2-(pyridin-2-ylimino)thiazolidin-4-ol derivatives were synthesized regioselectively using LiAlH4 at room temperature. The formation of M/P isomers was observed due to the restricted rotation around the N3-C-aryl single bond. Computational DFT study demonstrated that the OH group of the hemiaminal formed an intramolecular hydrogen bond with the pyridyl nitrogen during this restricted rotation, which presumably inhibited dehydration and stabilized the molecule.