Sulfuric Acid → 5-bromo-6-methoxy-3,4-dihydro-2H-naphthalen-1-one

HRID 63638Notes

Reaction equation

HRID 63638 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:10](=[CH:11][CH:12]=1)[C:9](=[O:13])[CH2:8][CH2:7][CH2:6]2.C1C(=O)N([Br:21])C(=O)C1.OS(O)(=O)=O>O>[Br:21][C:4]1[C:3]([O:2][CH3:1])=[CH:12][CH:11]=[C:10]2[C:5]=1[CH2:6][CH2:7][CH2:8][C:9]2=[O:13]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 141126-Methoxy-alpha-tetraloneHCID 67184N-bromobutanimide

Product 1

HCID 43042315-bromo-6-methoxy-3,4-dihydro-2H-naphthalen-1-oneYield 41.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
60 °C

Procedure

To a suspension of 6-methoxy-1-tetralone (2.0 g, 11.4 mmol) and NBS (2.0 g, 11.4 mmol) in H2O (30 mL) was added conc. H2SO4 (1.2 mL, 22.7 mmol) at rt. The reaction was stirred at 60° C. for 3 h. The mixture was filtered, and concentrated. Purification by prep-HPLC gave 1.2 g (41%) of the title compound as a white solid. 1H NMR (400 MHz, CDCl3): δ 2.13-2.18 (2H, m), 2.61 (2H, t, J=6.0 Hz), 3.03 (2H, t, J=6.0 Hz), 3.97 (3H, s), 6.88 (1H, d, J=8.8 Hz), 8.06 (1H, d, J=8.8 Hz). [M+H] Calc'd for C11H11BrO2, 255, 257. Found, 255, 257.

Workup

  1. filtrationThe mixture was filtered
  2. concentrationconcentrated
  3. customPurification

Sources & evidence

ORD record
ord-2761bd81722b4fda9bbec84e3348fa4d
Source dataset
uspto-grants-2016_09
Patent number
US09447046B2

Reaction notes

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