Hydrochloric Acid → 5-Bromo-7-methoxy-2-benzofurancarboxylic acid

HRID 361884

反応式

HRID 361884 の反応式
[OH-:1].[Na+].BrBr.[C:5]([C:8]1[O:9][C:10]2[C:16]([O:17][CH3:18])=[CH:15][C:14]([Br:19])=[CH:13][C:11]=2[CH:12]=1)(=[O:7])C.Cl>O1CCOCC1>[Br:19][C:14]1[CH:15]=[C:16]([O:17][CH3:18])[C:10]2[O:9][C:8]([C:5]([OH:7])=[O:1])=[CH:12][C:11]=2[CH:13]=1

参加物

6

反応物 4

HCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 24408BromineHCID 14913661-(5-Bromo-7-Methoxy-1-Benzofuran-2-Yl)Ethan-1-One

生成物 1

HCID 33589715-Bromo-7-methoxy-2-benzofurancarboxylic acid

試薬・触媒・溶媒 1

HCID 312751,4-Dioxane溶媒

反応条件

温度
60 °C

実験手順

To 107.6 ml of 5N sodium hydroxide aqueous solution was added dropwise 26.8 g of bromine at a temperature of -5° C. or below. To this was further added dropwise and slowly a 100 ml dioxane solution containing 15.0 g of 2-acetyl-5-bromo-7-methoxybenzofuran obtained in the above step a). After completion of the dropwise addition, the temperature of the resulting reaction solution was increased gradually to 60° C. and then stirred for 30 minutes. After cooling, the resulting reaction solution was adjusted to pH 2 with concentrated hydrochloric acid and then extracted with ethyl acetate. The resulting organic layer was concentrated to dryness, and crystals thus precipitated were collected by filtration to obtain 5-bromo-7-methoxy-2-benzofurancarboxylic acid. The thus obtained crystals were suspended in 200 ml of ethanol, and 10 ml of thionyl chloride was added dropwise to the suspension with stirring at room temperature. The resulting reaction solution was refluxed under heating for 2 hours. After cooling, the thus treated reaction solution was neutralized with saturated sodium bicarbonate aqueous solution, and then mixed with water to collect precipitated crystals by filtration. The crystals thus collected were purified by silica gel column chromatography using chloroform as an eluant to obtain 11.33 g of ethyl 5-bromo-7-methoxy-2-benzofurancarboxylate.

後処理

  1. additionTo this was further added dropwise
  2. customobtained in the above step a)
  3. additionAfter completion of the dropwise addition
  4. customthe temperature of the resulting reaction solution
  5. temperatureAfter cooling
  6. customthe resulting reaction solution
  7. extractionextracted with ethyl acetate
  8. concentrationThe resulting organic layer was concentrated to dryness, and crystals
  9. customthus precipitated
  10. filtrationwere collected by filtration

出典と根拠

ORDレコード
ord-1938b36fea4b4363b87cff91f7082adb
出典データセット
uspto-grants-1999_02
特許番号
US05866577

関連ノート

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