2,2-Dimethoxypropane → 5-Bromo-2,2-dimethylbenzo(d)(1,3)dioxole

HRID 1746066Notes

Reaction equation

HRID 1746066 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([OH:9])[C:5]([OH:8])=[CH:6][CH:7]=1.CO[C:12](OC)([CH3:14])[CH3:13]>O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C1C=CC=CC=1>[Br:1][C:2]1[CH:7]=[CH:6][C:5]2[O:8][C:12]([CH3:14])([CH3:13])[O:9][C:4]=2[CH:3]=1

Participants

5

Reactant 2

HCID 64952,2-DimethoxypropaneHCID 284874-Bromocatechol

Product 1

HCID 115938035-Bromo-2,2-dimethylbenzo(d)(1,3)dioxoleYield 63.3%

Reagents, catalysts & solvents 2

HCID 521998p-Toluenesulfonic acid monohydrateCatalystHCID 241BenzeneSolvent

Procedure

To benzene (50 mL) in a 250 mL round bottom flask was added 4-bromobenzene-1,2-diol (1 g, 5.29 mmol), 2,2-dimethoxypropane (2.204 g, 21.16 mmol), and p-toluene sulfonic acid monohydrate (0.050 g, 0.265 mmol). The flask was fitted with a Dean-Stark trap and heated to reflux for 18 h. Upon cooling, the reaction mixture was transferred to a separatory funnel and washed with 2 N NaOH solution (100 mL) and saturated NaCl solution (100 mL). The organic layer was dried with MgSO4, filtered, and concentrated to yield 5-bromo-2,2-dimethylbenzo[d][1,3]dioxole as a dark brown oil (767 mg, 63%): 1H NMR (400 MHz, CDCl3) δ 6.91-6.85 (m, 2H), 6.62-6.57 (m, 1H), 1.66 (s, 6H); 13C NMR (101 MHz, CDCl3) δ 146.81 (s), 144.25 (s), 123.64 (s), 121.02 (s), 112.05 (s), 109.40 (s), 108.46 (s), 25.83 (s); ESIMS m/z 230 ([M+H]+), 228 ([M−H]−).

Workup

  1. customThe flask was fitted with a Dean-Stark trap
  2. temperatureheated
  3. temperatureto reflux for 18 h
  4. temperatureUpon cooling
  5. customthe reaction mixture was transferred to a separatory funnel
  6. washwashed with 2 N NaOH solution (100 mL) and saturated NaCl solution (100 mL)
  7. dry with materialThe organic layer was dried with MgSO4
  8. filtrationfiltered
  9. concentrationconcentrated

Sources & evidence

ORD record
ord-e7f7da7f2dfa4cbdadb560230c4f947a
Source dataset
uspto-grants-2015_10
Patent number
US09149038B2

Reaction notes

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