Hydrogen Bromide → 2,3-Dihydro-6-hydroxy-2-methyl-4-benzofurancarboxylic acid

HRID 614001Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 614001
C[O:2][C:3]([C:5]1[CH:6]=[C:7]([O:15]C)[CH:8]=[C:9]2[O:13][CH:12]([CH3:14])[CH2:11][C:10]=12)=[O:4].Br>C(O)(=O)C>[OH:15][C:7]1[CH:8]=[C:9]2[O:13][CH:12]([CH3:14])[CH2:11][C:10]2=[C:5]([C:3]([OH:4])=[O:2])[CH:6]=1

Komponenten

4

Edukt 2

HCID 260Hydrogen BromideHCID 543897576-Methoxy-2-methyl-2,3-dihydro-benzofuran-4-carboxylic acid methyl ester

Produkt 1

HCID 213298282,3-Dihydro-6-hydroxy-2-methyl-4-benzofurancarboxylic acid

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 176Acetic AcidLösungsmittel

Versuchsvorschrift

To a solution of 35 grams of 2,3-dihydro-6-methoxy-2-methyl-4-benzofurancarboxylic acid methyl ester, prepared in Example 1, in 160 cc of acetic acid, 60 cc of 48%HBr are added and the resulting mixture is refluxed for 16 hours. After this time the reaction mixture is concentrated to dryness and the residue is dissolved in concentrated NaOH. The obtained solution, heated in a hot water-bath for 2 hours, is then cooled, acidified with concentrated HCl and extracted with ether. Evaporation of the ether extract affords a crude residue which is purified by column chromatography using a mixture CHCl3 -MeOH as the eluting system wherein the percentage of MeOH is gradually increased. The compound of the title, recovered from the last fractions (CHCl3 + 3% MeOH), is then crystallized from ethyl ether-petroelum ether. Yield 14.2 g (47 percent of theoretical). M.p. 225°-27° C.

Aufarbeitung

  1. temperaturethe resulting mixture is refluxed for 16 hours
  2. concentrationAfter this time the reaction mixture is concentrated to dryness
  3. dissolutionthe residue is dissolved in concentrated NaOH
  4. temperatureThe obtained solution, heated in a hot water-bath for 2 hours
  5. temperatureis then cooled
  6. extractionextracted with ether
  7. customEvaporation of the ether
  8. extractionextract

Quellen und Nachweise

ORD-Eintrag
ord-af888e30219e47a2b22c35ffab093562
Quelldatensatz
uspto-grants-1979_03
Patentnummer
US04143055

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