Reaktion #81552

Reaktionsgleichung

4,4-dimethyl-7-amino-1-tetralone

sodium nitrate

sodium nitrate

hydrobromic acid

→

title compound

4,4-Dimethyl-7-bromo-1-tetralone

Lösungsmittel

acetic acid

acetic acid

sulfuric acid

sulfuric acid

acetic acid

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigeprepared
2. 2
   Temperaturheating
3. 3
   workup.DISSOLUTIONto dissolve
4. 4
   workup.ADDITIONThe resulting solution was added slowly (over 10 minutes) to
5. 5
   TemperaturThe mixture was warmed to 90° C. for 10 minutes
6. 6
   Temperaturcooled
7. 7
   Extraktionextracted with ethyl acetate (2×200 mL)
8. 8
   EinengenThe combined organic phases were concentrated in vacuo
9. 9
   Sonstigethe residue chromatographed on silica gel (eluted with 3% ethyl acetate in hexane)

Vorschrift

To a cooled (10° C.) stirred solution of sodium nitrate (2.18 g, 13.92 mmol) in concentrated sulfuric acid (28.4 mL) and glacial acetic acid (26.27 mL) [prepared by adding sodium nitrate to cooled (10° C.) concentrated sulfuric acid, heating to dissolve, recooling and then adding glacial acetic acid] was added a solution of 4,4-dimethyl-7-amino-1-tetralone (XII) (5.0 g, 26.46 mmol) in glacial acetic acid (89 mL) over 10 mintues. The resulting solution was added slowly (over 10 minutes) to a heated (60° C.) solution of copper (I) bromide (16.66 g) in concentrated hydrobromic acid (159 mL). The mixture was warmed to 90° C. for 10 minutes, cooled, diluted with water (250 mL) and extracted with ethyl acetate (2×200 mL). The combined organic phases were concentrated in vacuo and the residue chromatographed on silica gel (eluted with 3% ethyl acetate in hexane) to give 1.95 g (Y: 29%) of the title compound; 1H-NMR (CDCl3): δ8.13 (d,J=2.3 Hz, 1H), 7.62 (dd, J=8.5, 2.3 Hz, 1H), 7.31 (d, J=8.5 Hz, 1H), 2.73 (t, J=7.0 Hz, 2H), 2.01 (t, J=7.0 HZ, 2H), 1.38 (s, 6H); MS (DCI) m/e: 253 (MH+).

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