Sulfuric Acid → 3,7-Dibromodibenzo[b,d]furan

HRID 565593Notes

Reaction equation

HRID 565593 reaction equation
N([O-])=O.[Na+].C[O:6][C:7]1[CH:12]=[C:11]([Br:13])[CH:10]=[CH:9][C:8]=1[C:14]1[CH:19]=[CH:18][C:17]([Br:20])=[CH:16][C:15]=1N.OS(O)(=O)=O.NC(N)=O>O>[Br:20][C:17]1[CH:16]=[CH:15][C:14]2[C:8]3[CH:9]=[CH:10][C:11]([Br:13])=[CH:12][C:7]=3[O:6][C:19]=2[CH:18]=1

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 1176UreaHCID 99984202-Methoxy-2'-amino-4,4'-dibromobiphenylHCID 23668193Sodium Nitrite

Product 1

HCID 5263563,7-Dibromodibenzo[b,d]furanYield 52.1%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
0 °C

Procedure

A solution of sodium nitrite (4.17 g, 60.5 mmol) in water (55.7 mL) was added slowly to a suspension of 2-methoxy-2′-amino-4,4′-dibromobiphenyl (16, 21.60 g, 60.50 mmol) in H2SO4 (14.82 g, 151.3 mmol) in water (52.7 mL), maintained below 2° C. The mixture was stirred for 2 h at 0° C., and then excess urea was added to destroy the unreacted nitrous acid. The reaction mixture was stirred overnight at room temperature, then overnight at 70° C. The solid formed was collected and recrystallized from benzene (120 mL) and methanol (100 mL) to give a beige solid (10.27 g, 52.09%): mp 199-200.5° C.; HPLC method 3 tR=20.99 min (100 area %); 1H NMR (300 MHz, CDCl3) δ 7.78 (d, J=8.2 Hz, 2 H), 7.74 (d, J=1.2 Hz, 2 H), 7.49 (dd, J1=8.2 Hz, J2=1.2 Hz, 2 H); EI-Ms m/z 324 (M+). Anal. (C12H6OBr2) C, H, N.

Workup

  1. temperaturemaintained below 2° C
  2. customto destroy the unreacted nitrous acid
  3. stirringThe reaction mixture was stirred overnight at room temperature
  4. customovernight
  5. customat 70° C
  6. customThe solid formed
  7. customwas collected
  8. customrecrystallized from benzene (120 mL) and methanol (100 mL)

Sources & evidence

ORD record
ord-342083244d364525ad61799c34ac22bc
Source dataset
uspto-grants-2001_01
Patent number
US06172104B2

Reaction notes

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