4-chloro-1,3-dihydroindol-2-one

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, m.p. 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 5.5 g of 4-chlorooxindole was dissolved in 80 ml of dioxane and 6.2 g of sodium borohydride was suspended in the resulting solution. 12.7 ml of trifluoroacetic acid (d=1.48) was added thereto dropwise at room temperature while stirring. After heat-refluxing the mixture for 4.5 hours, the solvent was removed therefrom under reduced pressure. Water was added to the residue and the water-insoluble materials were removed by filtration and washed with diethyl ether. The filtrate was extracted with diethyl ether and the ether layer was dried over anhydrous sodium sulfate followed by removing the solvent. The residue was distilled under reduced pressure to obtain 3.9 g of 4-chloroindoline as a colorless oily product having a boiling point of 135° C. at 10 mm Hg. After heat-refluxing the mixture for 4.5 hours the solvent was removed Water was added to the residue the water-insoluble materials were removed by filtration washed with diethyl ether The filtrate was extracted with diethyl ether the ether layer was dried over anhydrous sodium sulfate by removing the solvent The residue was distilled under reduced pressure

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of 22 g of sodium in 450 ml of anhydrous ethanol was added, portionwise, 43.5 g of 4-chloro-3-hydrazono-2-oxindole, and the resulting solution was heated under reflux for 30 minutes. The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water and decolorized using activated carbon. The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid. The precipitate which formed was recovered by filtration, dried and recrystallized from ethanol, giving 22.4 g of 4-chloro-2-oxindole, mp 216°-218° C. (dec). under reflux for 30 minutes The cooled solution was then concentrated to a gum, which was dissolved in 400 ml of water The resulting solution was poured onto a mixture of 1 liter of water and 45 ml of concentrated hydrochloric acid The precipitate which formed was recovered by filtration dried recrystallized from ethanol