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

HRID 614001ノート

反応式

HRID 614001 の反応式
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

参加物

4

反応物 2

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

生成物 1

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

試薬・触媒・溶媒 1

HCID 176Acetic Acid溶媒

実験手順

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.

後処理

  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

出典と根拠

ORDレコード
ord-af888e30219e47a2b22c35ffab093562
出典データセット
uspto-grants-1979_03
特許番号
US04143055

反応ノート

読み込み中…