Tetrahydrofuran → 2'-Methyl-3'-(2-thenoyl)acetophenone

HRID 258910Notes

Reaction equation

HRID 258910 reaction equation
Br[C:2]1[C:3]([C:9]2([CH3:14])[O:13]CCO2)=[C:4]([CH3:8])[CH:5]=[CH:6][CH:7]=1.[Mg].C1(C#N)[S:20][CH:19]=[CH:18][CH:17]=1.[Cl-].[NH4+].[O:25]1CC[CH2:27][CH2:26]1>>[CH3:8][C:4]1[C:3]([C:9](=[O:13])[C:14]2[S:20][CH:19]=[CH:18][CH:17]=2)=[CH:2][CH:7]=[CH:6][C:5]=1[C:26](=[O:25])[CH3:27]

Participants

6

Reactant 5

HCID 8028Tetrahydrofuran2×HCID 25517Ammonium ChlorideHCID 660872-ThiophenecarbonitrileHCID 5462224MagnesiumHCID 706381482-(3-Bromo-o-tolyl)-2-methyl-1,3-dioxolane

Product 1

HCID 213917902'-Methyl-3'-(2-thenoyl)acetophenone

Conditions

Temperature
0 °C

Procedure

To a stirred and refluxing Grignard-complex, previously prepared starting from 72 parts of 2-(3-bromo-o-tolyl)-2-methyl-1,3-dioxolane, 6.8 parts of magnesium and 180 parts of dry tetrahydrofuran, is added dropwise a solution of 30.6 parts of 2-thenonitrile in 90 parts of dry tetrahydrofuran. Upon completion, stirring at reflux is continued for 2 hours. The reaction mixture is allowed to stirr overnight at room temperature. After cooling to 0° C, the mixture is decomposed by the addition of 200 parts of a saturated ammonium chloride solution while keeping the temperature below 20° C. The product is extracted with 1200 parts of ether. The extract is washed three times with 300 parts of water and upon saturation of the ether-phase with gaseous hydrogen chloride, the ketimine-compound is separated as an oil. The ether is decanted and the oil is stirred and refluxed for 3 hours in 500 parts of a 6N hydrochloric acid solution. After cooling, the product is extracted with chloroform (2 × 225 parts). The extract is dried and evaporated. The residue is distilled twice, yielding 2'-methyl-3'-(2-thenoyl)acetophenone; bp. 185°-190° C at 0.4 mm. pressure.

Workup

  1. temperaturerefluxing Grignard-complex
  2. custompreviously prepared
  3. stirringUpon completion, stirring
  4. temperatureat reflux
  5. waitto stirr overnight at room temperature
  6. customthe temperature below 20° C
  7. extractionThe product is extracted with 1200 parts of ether
  8. washThe extract is washed three times with 300 parts of water
  9. customupon saturation of the ether-phase with gaseous hydrogen chloride, the ketimine-compound is separated as an oil
  10. customThe ether is decanted
  11. stirringthe oil is stirred
  12. temperaturerefluxed for 3 hours in 500 parts of a 6N hydrochloric acid solution
  13. temperatureAfter cooling
  14. extractionthe product is extracted with chloroform (2 × 225 parts)
  15. customThe extract is dried
  16. customevaporated
  17. distillationThe residue is distilled twice

Sources & evidence

ORD record
ord-d7b7b2efee704e2cae973dcc46776dee
Source dataset
uspto-grants-1977_07
Patent number
US04035376

Reaction notes

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