Abstract
An efficient synthesis of 3,3-di(1H-indol-3-yl)indolin-2-ones and 2,2-di(1H-indol-3-yl)-2H-acenaphthen-1-ones via a reaction of various isatins or acenaphthenequinone with indoles in the presence of p-methylbenzene sulfonic acid (p-TSA) in CH2Cl2 at room temperature is described. The advantages of this method include good reaction yield, simple workup procedure, and mild reaction condition.
GRAPHICAL ABSTRACT
Notes
a Reaction conditions: isatin 1a (1 mmol), indole 2a (2 mmol), solvent (5 mL).
b r.t. = room temperature.
c Isolated yields.
a Reaction conditions: isatin 1 (1 mmol), indole 2 (2 mmol), p-TSA (10 mol %), CH2Cl2 (5 mL), rt.
b Isolated yields.
c, d, e, f Yields of reported literature.[ Citation 26 , Citation 13 , Citation 16 , Citation 27 ]
a Reaction conditions: acenaphthenequinone 4 (1 mmol), indole 2 (2 mmol), p-TSA (10 mol %), CH2Cl2 (5 mL), rt.
b Isolated yields.
c Yields of reported literature.[ Citation 31 ]