Sulfuric Acid → 4-Hydroxyindan

Temperature

45 °C

4-Aminoindan (3.0 g) was added to a solution of concentrated sulphuric acid (2.4 mL) in water (15 mL). More water (15 mL) was added and the mixture cooled to SOC. A solution of sodium nitrite (1.71 g) in water (4.5 ml) was added portionwise to the mixture while maintaining the temperature below 5C. After addition was complete the mixture was allowed to Mann to room temperature and urea (0.29 g) was added. The mixture was stirred for a further 5 minutes before being heated at 45° C. for 30 minutes. The mixture was then cooled to room temperature and extracted with ethyl acetate. The combined organic extracts were washed with 2M aqueous sodium hydroxide (2×100 mL) and these aqueous extracts were then acidified with hydrochloric acid and extracted with ethyl acetate (3×100 mL). The combined organic extracts were then washed with brine and dried (Na2SO4) before being concentrated in vacuo. The resulting crude product was chromatographed over silica gel. Elution with ethyl acetate/hexanes (1:7) gave 4-hydroxyindan as an orange oil (1.0 g).

1. temperaturethe mixture cooled to SOC
2. additionAfter addition
3. customwas allowed to Mann to room temperature
4. temperatureThe mixture was then cooled to room temperature
5. extractionextracted with ethyl acetate
6. washThe combined organic extracts were washed with 2M aqueous sodium hydroxide (2×100 mL)
7. extractionextracted with ethyl acetate (3×100 mL)
8. washThe combined organic extracts were then washed with brine
9. dry with materialdried (Na2SO4)
10. concentrationbefore being concentrated in vacuo
11. customThe resulting crude product was chromatographed over silica gel
12. washElution with ethyl acetate/hexanes (1:7)

ORD record

ord-b2c69c0b72b04cee8800f016385e8d5d

Source dataset

uspto-grants-2014_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08669280B2