One-step construction of aminosquaraine backbone

摘要: Abstract One-step construction of the amino-substituted squaraine dye backbone was discovered unexpectedly in an amidation reaction. Under catalysis Mukaiyama's reagent, (4-dimethylamino)phenylacetic acid and bulky secondary amine 2,2,6,6-tetramethylpiperidine give reduced form aminosquaraine instead amide as major product. The can be oxidized to a dark-colored conjugated within seconds. method provides novel facile way functionalize four-membered core dye.