RESUMO
2-Cyanobenzothiazoles (CBTs) are useful building blocks for: 1) luciferin derivatives for bioluminescent imaging; and 2) handles for bioorthogonal ligations. A particularly versatile CBT is 6-amino-2-cyanobenzothiazole (ACBT), which has an amine handle for straight-forward derivatisation. Here we present an economical and scalable synthesis of ACBT based on a cyanation catalysed by 1,4-diazabicyclo[2.2.2]octane (DABCO), and discuss its advantages for scale-up over previously reported routes.
RESUMO
A three-component synthesis of polysubstituted pyridines has been developed, based upon the synthesis of 2-azadienes by a redox-neutral catalytic intermolecular aza-Wittig reaction and their subsequent Diels-Alder reactions. The two-pot process has been demonstrated using a range of aryl and heteroaromatic aldehydes, substituted α,ß-unsaturated acids and push-pull enamines, to give rapid access to diverse tri- and tetrasubstituted pyridines.