Isovanillin → 2-Bromoisovanillin

HRID 2068168Notes

Reaction equation

HRID 2068168 reaction equation
[O:1]=[CH:2][C:3]1[CH:11]=[CH:10][C:7]([O:8][CH3:9])=[C:5]([OH:6])[CH:4]=1.C([O-])(=O)C.[Na+].[Br:17]Br>C(O)(=O)C.[Fe]>[Br:17][C:4]1[C:5]([OH:6])=[C:7]([O:8][CH3:9])[CH:10]=[CH:11][C:3]=1[CH:2]=[O:1]

Participants

6

Reactant 3

HCID 12127IsovanillinHCID 24408BromineHCID 517045Sodium Acetate

Product 1

HCID 2240112-BromoisovanillinYield 79%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 176Acetic AcidSolvent2×

Procedure

To a stirred suspension of isovanillin (10 g, 66 mmol), powdered anhydrous sodium acetate (10.82 g, 0.132 mol) and iron powder (0.3 g, 5.4 mmol) in glacial acetic acid (60 mL) under argon, was added drop-wise over 15 min a solution of Br2 (3.7 mL, 0.0726 mol) in acetic acid (12.5 mL). The reaction temperature rose during the course of addition, and the mixture became viscous. After all the starting material was consumed, as determined by TLC, the mixture was poured onto ice cold water, and the resulting precipitate filtered under vacuum. The precipitate was washed several times with cold water and air-dried. Crystallization from boiling ethanol gave 8 (11.93 g, 79% yield) as a gray powder. Rf=0.10 (1:5 EtOAc/hexanes). M.p. 196-200° C. IR (thin film) 3215, 1662, 1588, 1561, 1491, 1273 cm−1. 1H NMR (300 MHz, CDCl3) δ 10.27 (1H, s), 7.59 (1H, d, J=9 Hz), 6.96 (1H, d, J=9 Hz), 6.02 (1H, bs), 4.00 (3H, s). 13C NMR (75 MHz, CDCl3) δ 56.58, 109.24, 112.84, 113.84, 122.74, 143.25, 151.65, 190.87. HRMS calcd. for C8H8O3Br (MH+) 230.9657. Found 230.9652.

Workup

  1. additionThe reaction temperature rose during the course of addition
  2. customAfter all the starting material was consumed
  3. additionthe mixture was poured onto ice cold water
  4. filtrationthe resulting precipitate filtered under vacuum
  5. washThe precipitate was washed several times with cold water
  6. customair-dried
  7. customCrystallization

Sources & evidence

ORD record
ord-dd14ab2c3c844670a6026ef6d1c79a1a
Source dataset
uspto-grants-2012_10
Patent number
US08293927B2

Reaction notes

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