Isatin → 3-Hydroxy-3-phenyl-1,3-dihydroindol-2-one

As another non-limiting example, 3-(5-tert-butyl-2-hydroxy-phenyl)-3-phenyl-1,3-dihydro-indol-2-one (compound 1181) was synthesized by adding dropwise a 1M solution of phenylmagnesiumbromide (0.33 mole) to isatin (15 g, 0.1 mole) in 60 mL THF at 0° C. The resulting mixture was allowed to warm to room temperature and let stir at room temperature for 12 hours. The reaction mixture was quenched with a saturated solution of NH4Cl (100 mL) and diluted with 100 mL of dichloromethane. The layers were separated, the organic layer was washed with water followed by brine, dried over Na2SO4, and filtered. The filtrate was concentrated in vacuo to yield 20.1 g (90 %) of 3-hydroxy-3-phenyl-1,3-dihydro-indol-2-one. A mixture of the above solid (2.5 g, 10 mmole), p-t-Bu-phenol (1.5 g, 10 mmol), p-toluenesulfonic acid (3 g) in 40 mL dichloroethane, was heated to 95° C. for six hours. The mixture was cooled and filtered. The filtrate was concentrated in vacuo to yield 2.4 g (66%) of the desired product (compound 1181).