Phosphoric Acid → 4,5,6,7-Tetrahydro-4-oxothionaphthene

HRID 962847Notes

Reaction equation

HRID 962847 reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH2:6][CH2:7][CH2:8][C:9]([OH:11])=O.C(OC(=O)C)(=O)C.P(=O)(O)(O)O>O>[CH2:7]1[CH2:8][C:9](=[O:11])[C:3]2[CH:4]=[CH:5][S:1][C:2]=2[CH2:6]1

Participants

5

Reactant 3

HCID 1004Phosphoric AcidHCID 7918Acetic AnhydrideHCID 783864-(2-Thienyl)Butyric Acid

Product 1

HCID 834184,5,6,7-Tetrahydro-4-oxothionaphtheneYield 88.9%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

4-(2-Thienyl)butyric acid (28.42 g, 167 mmol) was placed in a round bottom flask with acetic anhydride (30 mL) and phosphoric acid (0.6 mL), and heated to reflux for 3.2 hours. The reaction mixture was poured into 100 mL of water, extracted with ethyl acetate, washed with brine, dried over MgSO4, and concentrated in vacuo to give a brown oil (22.60 g) which was vacuum distilled (1 mm Hg, 107°-115° C.) to give a white solid (13.08 g, 51%): mp 34°-40° C.); 1H NMR (CDCl3) 300 MHz 7.29 (d, J=5.2 Hz, 1H), 6.99 (d, J=5.2 Hz, 1H, 2.95 (t, J=6.0 Hz, 2H), 2.47(m, 2H), 2.13(m, 2H). M+H=153.

Workup

  1. temperatureheated
  2. temperatureto reflux for 3.2 hours
  3. extractionextracted with ethyl acetate
  4. washwashed with brine
  5. dry with materialdried over MgSO4
  6. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-efcca95a23374a6c92307a68aa24f83c
Source dataset
uspto-grants-1998_06
Patent number
US05760068

Reaction notes

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