Thiophene → alpha-N-benzoylamino-2-acetylthiophene

HRID 2352044Notes

Reaction equation

HRID 2352044 reaction equation
[C:1]1([CH:7]2[N:11]=[CH:10][C:9](=[O:12])[O:8]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[Cl-].[Al+3].[Cl-].[Cl-].[S:17]1[CH:21]=[CH:20][CH:19]=[CH:18]1>C(Cl)Cl>[C:7]([NH:11][CH2:10][C:9]([C:18]1[S:17][CH:21]=[CH:20][CH:19]=1)=[O:12])(=[O:8])[C:1]1[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1

Participants

5

Reactant 3

HCID 8030ThiopheneHCID 6451240Aluminum(III) ChlorideHCID 532492532-Phenyl-1,3-oxazol-5-one

Product 1

HCID 13105421alpha-N-benzoylamino-2-acetylthiopheneYield 42.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A 500 mL, round-bottomed, 3-necked flask was charged with 23.0 g (142.7 mmol) of 2-phenyl-5-oxazolone, and 250 mL of dried methylene chloride, and cooled in an ice bath under a nitrogen atmosphere. Using a powder addition funnel, 57.0 g (3.0 equiv.) of aluminum chloride was added over a period of 1 hour to the stirred reaction mixture. After holding for 20 minutes the gradual addition of thiophene (14.4 mL, 1.22 equiv.) was carried out over a 1 hour period. The reaction mixture was then stirred overnight (15 hours) at room temperature, and the reaction was then quenched by the addition of iced water. The product was extracted several times with methylene chloride, and the combined extracts were dried over anhydrous sodium sulfate, filtered, then stripped on a rotary evaporator. After drying at the pump the crude product (33.96 g) was recrystallized from hot methanol with activated charcoal treatment to yield 14.77 g (42.2%) of α-N-benzoylamino-2-acetylthiophene was a white solid; mp 153°-154° C. Re-work of the mother liquor afforded a second batch of product (mp 140°-146° C.), bringing the total yield of product to 47.3%.

Workup

  1. temperaturecooled in an ice bath under a nitrogen atmosphere
  2. additiona powder addition funnel
  3. waitwas carried out over a 1 hour period
  4. customthe reaction was then quenched by the addition of iced water
  5. extractionThe product was extracted several times with methylene chloride
  6. dry with materialthe combined extracts were dried over anhydrous sodium sulfate
  7. filtrationfiltered
  8. customstripped on a rotary evaporator
  9. dry with materialAfter drying at the pump the crude product (33.96 g)
  10. customwas recrystallized from hot methanol with activated charcoal treatment

Sources & evidence

ORD record
ord-d14bb1e282ec4d1f96a33d20d9bdb97f
Source dataset
uspto-grants-1989_10
Patent number
US04874876

Reaction notes

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