Hydrogen Bromide → 5-bromo-2,3-dihydro-1H-indene

Temperature

-5 °C

5-Aminoindane was treated with concentrated hydrobromic acid. The suspension was cooled to −5° C., and 5M sodium nitrite solution was added at a temperature between 0° C. to 5° C. in period of 30 minutes through an addition funnel. Stirring was continued for 20 minutes at 0° C. to 5° C. The reaction mixture was now very dark fluid slurry. In a second reaction vessel, a solution of copper (I) bromide in concentrated hydrobromic acid had been prepared and preheated to 40° C. When the diazonium salt slurry was added in portions, a very slow gas evolution was observed which became vehement when heating to 60° C. After stirring at 60° C. for 40 min, the gas evolution ceased. The mixture was poured onto water. The product was extracted twice with ethyl acetate. Some of the precipitated copper bromide was removed by filtration to facilitate phase separation. The organic extracts were washed twice with water and one time with brine. The combined organic extracts were dried over anhydrous magnesium sulfate, filtered, and evaporated to dryness. After flash chromatography, the title compound was obtained as pale yellow oil.

1. custompreheated to 40° C
2. temperatureheating to 60° C
3. stirringAfter stirring at 60° C. for 40 min
4. additionThe mixture was poured onto water
5. extractionThe product was extracted twice with ethyl acetate
6. customSome of the precipitated copper bromide was removed by filtration
7. customphase separation
8. washThe organic extracts were washed twice with water and one time with brine
9. dry with materialThe combined organic extracts were dried over anhydrous magnesium sulfate
10. filtrationfiltered
11. customevaporated to dryness

ORD record

ord-3e20827ed70b4fa18ae21642bc831faf

Source dataset

uspto-grants-2015_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09034921B2