Hydrogen Bromide → 2-Bromo-6-methoxynaphthalene

HRID 1249001Notes

Reaction equation

HRID 1249001 reaction equation
BrBr.COC1C=CC2C(=CC=CC=2)C=1.Br.Br[C:17]1[C:26]2[C:21](=[CH:22][C:23]([Br:27])=[CH:24][CH:25]=2)[CH:20]=[CH:19][C:18]=1[O:28][CH3:29]>CC(O)=O.O.[Fe]>[CH3:29][O:28][C:18]1[CH:19]=[CH:20][C:21]2[C:26](=[CH:25][CH:24]=[C:23]([Br:27])[CH:22]=2)[CH:17]=1

Participants

8

Reactant 4

HCID 260Hydrogen BromideHCID 71192-MethoxynaphthaleneHCID 24408BromineHCID 35030571,6-Dibromo-2-methoxynaphthalene

Product 1

HCID 787862-Bromo-6-methoxynaphthalene

Reagents, catalysts & solvents 3

HCID 23925IronCatalystHCID 176Acetic AcidSolvent2×HCID 962WaterSolvent

Conditions

Temperature
30 °C

Procedure

A solution of 81 g of bromine in 25 cm3 of CH3COOH was added over 35 minutes to a very well stirred suspension of 39.25 g of 2-methoxy-naphthalene in 125 cm3 of glacial CH3COOH, heated to 30° C., keeping the temperature at 40°-45° C., avoiding that the formed hydrobromic acid leaves the reaction medium; when the addition was over, the bulk was stirred for 1.5 h at 45° C. in order to complete the reaction. 14 g of iron in the form of powder were then added, in small doses, over 1.5 hours, slowing down at intervals the reaction exothermicity by means of a cold bath; one stirred at 45° C. till 1,6-dibromo-2-methoxy-naphthalene disappeared (on thin layer chromatography) and then the bulk was diluted with 0.5 liters of H2O. Then the compound was filtered, washed with H2O and dissolved in CH2Cl2 ; lastly the chloromethylenic solution was washed with NaOH at 5%, dehydrated and evaporated. 55.2 g of raw 2-methoxy-6-bromo-naphthalene were obtained; after a crystallization from 250 cm3 of isobutanol, 45 g of pure product were obtained (gas-chromatographic analysis) having a melting point ranging between 105° and 106° C.

Workup

  1. customat 40°-45° C.
  2. customleaves the reaction medium
  3. additionwhen the addition
  4. customthe reaction
  5. filtrationThen the compound was filtered
  6. washwashed with H2O
  7. dissolutiondissolved in CH2Cl2
  8. washlastly the chloromethylenic solution was washed with NaOH at 5%
  9. customevaporated

Sources & evidence

ORD record
ord-83f9d6b643c6483288b4430eaf500d2f
Source dataset
uspto-grants-1986_12
Patent number
US04628123

Reaction notes

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