Sulfuric Acid → 2-Methoxy-9H-thioxanthen-9-one

HRID 2373115Notes

Reaction equation

HRID 2373115 reaction equation
CO[C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][C:4]=1[S:9][C:10]1[CH:18]=[CH:17][CH:16]=[CH:15][C:11]=1[C:12]([OH:14])=O.[C:19](OC(=O)C)(=[O:21])C.S(=O)(=O)(O)O>>[CH3:19][O:21][C:7]1[CH:8]=[CH:3][C:4]2[S:9][C:10]3[C:11](=[CH:15][CH:16]=[CH:17][CH:18]=3)[C:12](=[O:14])[C:5]=2[CH:6]=1

Participants

4

Reactant 3

HCID 1118Sulfuric AcidHCID 7918Acetic AnhydrideHCID 155738872-[(2-Methoxyphenyl)sulfanyl]benzoic acid

Product 1

HCID 6179842-Methoxy-9H-thioxanthen-9-one

Conditions

Temperature
80 °C

Procedure

Finally, 2-methoxythioxanthen-9-one (S-17) was prepared. To a mixture of 2-(2-methoxyphenylthio)benzoic acid (11.0 g, 42 mmol) and 43.1 g (423 mmol) of acetic anhydride was added dropwise 4.14 g (42 mmol) of concentrated sulfuric acid. The mixture was heated at 80° C. for 4 h, cooled to ambient, and poured very slowly onto 500 g of ice. The precipitate was extracted with dichloromethane, and the extract was washed with 10% aqueous NaHCO3 and then with brine. The solution was dried (MgSO4), passed through a short column of silica gel, and concentrated to deposit an orange solid. The product was purified by successive recrystallizations from isopropanol and from toluene/heptane. 1H NMR (CDCl3): δ 3.95 (s, 3H), 7.27 (dd, 1H), 7.5 (m, 2H), 7.6 (m, 2H), 8.09 (d, 1H), 8.64 (d 1H).

Workup

  1. temperaturecooled
  2. extractionThe precipitate was extracted with dichloromethane
  3. washthe extract was washed with 10% aqueous NaHCO3
  4. dry with materialThe solution was dried (MgSO4)
  5. concentrationconcentrated
  6. customThe product was purified by successive recrystallizations from isopropanol and from toluene/heptane

Sources & evidence

ORD record
ord-0fca29a57f3b4aef8da59bce1771ecff
Source dataset
uspto-grants-2008_12
Patent number
US07459263B2

Reaction notes

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