The synthesis of trifunctional isomeric benzothiazoles derived from nitroanthranilic
acids and their corresponding anthranilonitrile analogues is studied. Compared to
previous work, the reaction sequence affords convenient access to hitherto undescribed
2-cyanobenzothiazoles. For further synthetic applications of these polyfunctional
compounds, a hydrolysis–decarboxylation sequence is performed in an acidic medium
(HCl or HBr), leading to an enlarged array of relevant building blocks.
Key words
N-arylcyanothioformamides - 4,5-dichloro-1,2,3-dithiazolium chloride -
N-arylimino-1,2,3-dithiazoles - 2-cyanobenzothiazoles - anthranilic acid - anthranilonitrile
- intramolecular C–S bond formation - decyanation