Hydrogen Bromide → 7-Bromo-4,4-dimethyl-1,2,3,4-tetrahydronaphthalen-1-one

HRID 53274

Reaction equation

HRID 53274 reaction equation
[N+]([O-])([O-])=O.[Na+].[CH3:6][C:7]1([CH3:19])[C:16]2[C:11](=[CH:12][C:13](N)=[CH:14][CH:15]=2)[C:10](=[O:18])[CH2:9][CH2:8]1.[BrH:20]>S(=O)(=O)(O)O.C(O)(=O)C.O.[Cu]Br>[CH3:6][C:7]1([CH3:19])[C:16]2[C:11](=[CH:12][C:13]([Br:20])=[CH:14][CH:15]=2)[C:10](=[O:18])[CH2:9][CH2:8]1

Participants

8

Reactant 3

HCID 260Hydrogen BromideHCID 24268Sodium Nitrate2×HCID 154628417-Amino-4,4-dimethyl-3,4-dihydronaphthalen-1(2H)-one

Product 1

HCID 107533577-Bromo-4,4-dimethyl-1,2,3,4-tetrahydronaphthalen-1-one

Reagents, catalysts & solvents 4

HCID 24593copper(I) bromideCatalystHCID 176Acetic AcidSolvent3×HCID 962WaterSolventHCID 1118Sulfuric AcidSolvent2×

Conditions

Temperature
10 °C

Procedure

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+).

Workup

  1. customprepared
  2. temperatureheating
  3. dissolutionto dissolve
  4. additionThe resulting solution was added slowly (over 10 minutes) to
  5. temperatureThe mixture was warmed to 90° C. for 10 minutes
  6. temperaturecooled
  7. extractionextracted with ethyl acetate (2×200 mL)
  8. concentrationThe combined organic phases were concentrated in vacuo
  9. customthe residue chromatographed on silica gel (eluted with 3% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-157bc2b7e95c4c77b3662d8a58137f33
Source dataset
uspto-grants-1997_04
Patent number
US05618839

Linked notes

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