Sulfuric Acid → 4-Bromo-2,2-dimethyl-2,3-dihydrobenzofuran

HRID 233604

反応式

HRID 233604 の反応式
N[C:2]1[C:10]2[O:9][C:8]([CH3:12])([CH3:11])[CH2:7][C:6]=2[C:5]([Br:13])=[CH:4][CH:3]=1.C1(C)C=CC=CC=1.S(=O)(=O)(O)O.N([O-])=O.[Na+]>C(O)C>[Br:13][C:5]1[C:6]2[CH2:7][C:8]([CH3:12])([CH3:11])[O:9][C:10]=2[CH:2]=[CH:3][CH:4]=1

参加物

6

反応物 4

HCID 1118Sulfuric AcidHCID 1140TolueneHCID 23668193Sodium NitriteHCID 537220087-Amino-4-bromo-2,3-dihydro-2,2-dimethylbenzofuran

生成物 1

HCID 539891274-Bromo-2,2-dimethyl-2,3-dihydrobenzofuran収率 31.1%

試薬・触媒・溶媒 1

HCID 702Ethanol溶媒

反応条件

温度
50 °C

実験手順

A stirred solution of 12.3 grams (0.051 mole) of 7-amino-4-bromo-2,3-dihydro-2,2-dimethylbenzofuran and 30 mL of toluene in 200 mL of ethanol is cooled in an ice-bath, and 5.6 mL (0.102 mole) of concentrated sulfuric acid is added slowly, followed by 5.6 grams (0.082 mole) of sodium nitrite. Upon completion of addition, the ice-bath is removed, and the reaction mixture is warmed to 50° C. The reaction mixture temperature is then brought to about 75° C., where it is stirred for 30 minutes. After this time the reaction mixture is heated at reflux for one hour and then is poured into 200 mL of water. The mixture is extracted with two 150 mL portions of diethyl ether. The combined extracts are dried with magnesium sulfate and filtered. The filtrate is concentrated under reduced pressure to a residual oil. The oil is subjected to column chromatography on silica gel. Elution is accomplished using petroleum ether. The product-containing fractions are combined and concentrated under reduced pressure, yielding 3.6 grams of 4-bromo-2,3-dihydro-2,2-dimethylbenzofuran. The NMR spectrum is consistent with the proposed structure.

後処理

  1. additionUpon completion of addition
  2. customthe ice-bath is removed
  3. customis then brought to about 75° C.
  4. temperatureAfter this time the reaction mixture is heated
  5. temperatureat reflux for one hour
  6. additionis poured into 200 mL of water
  7. extractionThe mixture is extracted with two 150 mL portions of diethyl ether
  8. dry with materialThe combined extracts are dried with magnesium sulfate
  9. filtrationfiltered
  10. concentrationThe filtrate is concentrated under reduced pressure to a residual oil
  11. washElution
  12. concentrationconcentrated under reduced pressure

出典と根拠

ORDレコード
ord-1e00cde85a8b4418948718126feeb20a
出典データセット
uspto-grants-1997_01
特許番号
US05593998

関連ノート

読み込み中…