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.