sulfuric acid; zinc in ethanol; water T=90°C;

titanium tetrachloride; zinc in tetrahydrofuran T=20°C; 0.0833333 h; Inert atmosphere;

1: With potassium hydroxide; iodine in DMF (N,N-dimethyl-formamide) T=20°C; 0.5 h; 2: With sodium sulfite in DMF (N,N-dimethyl-formamide); water T=20°C; 0.25 h; 3: With phosphoric acid in 2-methoxy-ethanol T=100°C; 48 h; Heating / reflux;

trifluoroacetic acid in dichloromethane T=20°C; 0.666667 h; Inert atmosphere;

1: 1.) sodium ethoxide / 1.) overnight, room temp.; reflux, 10 min; 2.) H2O, reflux, 2 h 2: 86.4 percent / H2O2 (30percent), NaOH / H2O / 1 h / 5 °C 3: 87.1 percent / Zn, H2SO4 (50percent) / ethanol / 3 h / 90 °C View Scheme

1: 86.4 percent / H2O2 (30percent), NaOH / H2O / 1 h / 5 °C 2: 87.1 percent / Zn, H2SO4 (50percent) / ethanol / 3 h / 90 °C View Scheme

1: 1.) NaNO2, HBr (48percent); 2.) CuBr, HBr (48percent) / 1.) H2O, below 0 deg C; 2.) 90 deg C, 0.5 h 2: 1.) sodium ethoxide / 1.) overnight, room temp.; reflux, 10 min; 2.) H2O, reflux, 2 h 3: 86.4 percent / H2O2 (30percent), NaOH / H2O / 1 h / 5 °C 4: 87.1 percent / Zn, H2SO4 (50percent) / ethanol / 3 h / 90 °C View Scheme

1: With borane-THF in tetrahydrofuran T=20°C; 2: With hydrogenchloride; methanol; water in tetrahydrofuran T=0 - 20°C; 1 h; 3: With sodium hydroxide in tetrahydrofuran; methanol; water pH=8 - 9;

1: 4-bromo-1,3-dihydro-2H-indol-2-one With sodium hydride in o-xylene T=110 - 135°C; Inert atmosphere; 2: dimethyl sulfate in o-xylene 1 h; Inert atmosphereHeating;

1.1: borane-THF / tetrahydrofuran / 20 °C 1.2: 1 h / 0 - 20 °C 1.3: pH 8 - 9 2.1: acetonitrile / 20 °C View Scheme