Author(s): Edgars Abele, Tatjana Beresneva
Journal: Heterocyclic Letters
ISSN 2231-3087
Volume: 3;
Issue: 3;
Start page: 397;
Date: 2013;
Original page
Keywords: copper catalysis | 1 | 3-dihydrobenzimidazol-2-thione | phase transfer catalysis | imidazo[2 | 1-b]thiazoles | pyrimido[2 | 1-b]benzothiazol-4-one
ABSTRACT
A simple one-flask method for the selective preparation of benzo- and pyrido-fused imidazo[2,1- b]thiazoles and pyrimido[2,1-b]benzothiazol-4-one from corresponding thiones and 1-bromo-2- iodobenzenes or 2,3-dibromopyridines in the bicatalytic system solid KOH / CuI / 1,10- phenanthroline / Bu4NBr / DMF has been developed. Reaction of 1,3-dihydrobenzimidazol-2- thione with 3-bromo-4-iodotoluene in the above system leads to 5-methylbenzimidazo[2,1- b]benzothiazole as single cyclization product by selective stepwise S- and N-arylation tandem reaction.
Journal: Heterocyclic Letters
ISSN 2231-3087
Volume: 3;
Issue: 3;
Start page: 397;
Date: 2013;
Original page
Keywords: copper catalysis | 1 | 3-dihydrobenzimidazol-2-thione | phase transfer catalysis | imidazo[2 | 1-b]thiazoles | pyrimido[2 | 1-b]benzothiazol-4-one
ABSTRACT
A simple one-flask method for the selective preparation of benzo- and pyrido-fused imidazo[2,1- b]thiazoles and pyrimido[2,1-b]benzothiazol-4-one from corresponding thiones and 1-bromo-2- iodobenzenes or 2,3-dibromopyridines in the bicatalytic system solid KOH / CuI / 1,10- phenanthroline / Bu4NBr / DMF has been developed. Reaction of 1,3-dihydrobenzimidazol-2- thione with 3-bromo-4-iodotoluene in the above system leads to 5-methylbenzimidazo[2,1- b]benzothiazole as single cyclization product by selective stepwise S- and N-arylation tandem reaction.
