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

HRID 2084717Notes

Reaction equation

HRID 2084717 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-de2c17a601b744cf9ab4952748a67f99
Source dataset
uspto-grants-2004_04
Patent number
US06716991B1

Reaction notes

Loading…