Structural influences on the oxidation of a series of 2-benzothiazoline analogs

We have examined the molecular and electronic structures of a number of benzothiazoline (Bt) and benzothiazole (oBt) analogs that possess phenyl and heterocycle substituents at the 2-position and discuss the ground-state factors that influence the relative rates at which these benzothiazolines are oxidized to benzothiazoles. Our studies indicate that the substituent at the 2-position in the benzothiazoline plays a fundamental role in governing the susceptibility of the species to oxidize. Our calculations for this series of compounds suggest that benzothiazolines that possess a heterocyclic R group oxidize faster than those with a phenyl group. The establishment of a favorable electrostatic interaction between the heteroatoms of the R and Bt/oBt fragments is a primary influence on this reaction while the establishment of π conjugation across the CRCoBt bond is a minor effect.

► Synthesis and characterization of substituted benzothiazoles and benzothiazolines. ► X-ray studies differentiating between the thiazoline and thiazole forms. ► Density functional calculations of the species. ► Discussion of the influence of electrostatic interactions in the oxidation process. ► Discussion of π conjugation across the phenyl/benzothiazole parts of the molecule.