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

HRID 1941704Notes

Reaction equation

HRID 1941704 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-51ff5a5943cd4c338f7a97af5a2cf85e
Source dataset
uspto-grants-2013_03
Patent number
USRE044048E1

Reaction notes

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