Ethanol → ethyl 8-bromo-6-methoxy-4-oxo-4H-chromene-2-carboxylate

HRID 2414482Notes

Reaction equation

HRID 2414482 reaction equation
S(=O)(=O)(O)O.[Br:6][C:7]1[CH:21]=[C:20]([O:22][CH3:23])[CH:19]=[CH:18][C:8]=1[O:9]/[C:10](=[CH:14]\[C:15]([OH:17])=O)/[C:11]([OH:13])=[O:12].[CH2:24](O)[CH3:25]>>[Br:6][C:7]1[CH:21]=[C:20]([O:22][CH3:23])[CH:19]=[C:18]2[C:8]=1[O:9][C:10]([C:11]([O:13][CH2:24][CH3:25])=[O:12])=[CH:14][C:15]2=[O:17]

Participants

4

Reactant 3

HCID 702EthanolHCID 1118Sulfuric AcidHCID 69270394(2Z)-2-(2-bromo-4-methoxyphenoxy)-2-butenedioic acid

Product 1

HCID 22142256ethyl 8-bromo-6-methoxy-4-oxo-4H-chromene-2-carboxylateYield 50%

Procedure

Sulfuric acid (50 ml) was added to (2Z)-2-(2-bromo-4-methoxyphenoxy)-2-butenedioic acid (24.3 g, 86.6 mmol; as prepared in Reference Example 2b above). After heating the mixture with a heat gun for 5-10 min a clear deep brown solution was obtained. This solution was slowly added to refluxing absolute ethanol (250 ml). After the addition the reaction was refluxed for 30 min then allowed to cool. Crystals started to form after 20 min and the reaction was put in the refrigerator overnight. The solid was filtered, washed with cold ethanol/water 9:1 and dried to give ethyl 8-bromo-6-methoxy-4-oxo-4H-chromene-2-carboxylate as an off-white solid (12.3 g, 50% yield, mp 159-161° C.).

Workup

  1. temperatureAfter heating the mixture with a heat gun for 5-10 min a clear deep brown solution
  2. customwas obtained
  3. additionThis solution was slowly added
  4. additionAfter the addition the reaction
  5. temperaturewas refluxed for 30 min
  6. temperatureto cool
  7. customto form after 20 min
  8. customwas put in the refrigerator overnight
  9. filtrationThe solid was filtered
  10. washwashed with cold ethanol/water 9:1
  11. customdried

Sources & evidence

ORD record
ord-38cff3927c3c4a27a801a8c9b004e7b7
Source dataset
uspto-grants-2004_11
Patent number
US06812225B2

Reaction notes

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