1,2-Dimethyl-3-nitrobenzene → 2-(2-Methyl-6-nitrophenyl)acetic acid

Diethyl oxalate (30 mL) in 20 mL dry ether was added with stirring to 19 g potassium ethoxide suspended in 50 mL of dry ether. The mixture was cooled in an ice bath and 20 mL of 3-nitro-o-xylene in 20 mL of dry ether was slowly added. The thick dark red mixture was heated to reflux for 0.5 hr, concentrated to a dark red solid, and treated with 10% sodium hydroxide until almost all of the solid dissolved. The dark red mixture was treated with 30% hydrogen peroxide until the red color changed to yellow. The mixture was treated alternately with 10% sodium hydroxide and 30% hydrogen peroxide until the dark red color was no longer present. The solid was filtered and the filtrate acidified with 6 N hydrochloric acid. The resulting precipitate was collected by vacuum filtration, washed with water, and dried under vacuum to give 9.8 g (45% yield) of 2-methyl-6-nitrophenylacetic acid as an off-white solid. The solid was hydrogenated in methanol over 10% palladium on carbon to give 9.04 g of 4-methyl-2-oxindole as a white solid.

1. temperatureThe mixture was cooled in an ice bath
2. temperatureThe thick dark red mixture was heated
3. temperatureto reflux for 0.5 hr
4. concentrationconcentrated to a dark red solid
5. additiontreated with 10% sodium hydroxide until almost all of the solid
6. dissolutiondissolved
7. additionThe dark red mixture was treated with 30% hydrogen peroxide until the red color
8. additionThe mixture was treated alternately with 10% sodium hydroxide and 30% hydrogen peroxide until the dark red color
9. filtrationThe solid was filtered
10. filtrationThe resulting precipitate was collected by vacuum filtration
11. washwashed with water
12. customdried under vacuum

ORD record

ord-32d7411d620f4a8c831a15609b4b3542

Source dataset

uspto-grants-2002_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06395734B1