Trifluoroacetic anhydride → 7-Methoxy-1H-isothiochromen-4(3H)-one

HRID 865307Notes

Reaction equation

HRID 865307 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:12]=[CH:13][CH:14]=1)[CH2:6][S:7][CH2:8][C:9](O)=[O:10].FC(F)(F)C(OC(=O)C(F)(F)F)=O.C([O-])([O-])=O.[Na+].[Na+]>FC(F)(F)C(O)=O>[CH3:1][O:2][C:3]1[CH:4]=[C:5]2[C:12]([C:9](=[O:10])[CH2:8][S:7][CH2:6]2)=[CH:13][CH:14]=1

Participants

5

Reactant 3

HCID 9845Trifluoroacetic anhydrideHCID 10340Sodium CarbonateHCID 323071NSC281803

Product 1

HCID 3232557-Methoxy-1H-isothiochromen-4(3H)-oneYield 49%

Reagents, catalysts & solvents 1

HCID 6422Trifluoroacetic acidSolvent

Procedure

3-methoxybenzylmercaptoacetic acid from Step 2 (10.82 g) was dissolved in trifluoroacetic acid (50 mL). Trifluoroacetic acid anhydride (25 mL) was added and the reaction stirred under a nitrogen atmosphere for 0.25 hours. At this time, TLC showed no starting material. The solution was carefully poured into 10% Na2CO3 solution (500 mL) which was stirring vigorously. The organics were extracted into ether (500 mL) and washed with brine (300 mL), dried over MgSO4 and concentrated in vacuo. The resulting brown solid was purified by silica gel chromatography eluting with 20% ethyl acetate in hexane to yield 7-methoxyisothiochroman-4-one (4.84 g, 49%): 1H NMR (CDCl3) δ=3.48p (t, 2H, J=0.8 Hz), 3.83p (s, 3H), 3.84p (s, 2H), 6.6p (d, 1H, J=2.4 Hz), 6.83p (dd, 1H, J=2.4, 8.9 Hz), 8.0p (d, H, J=8.9 Hz).

Workup

  1. stirringwas stirring vigorously
  2. extractionThe organics were extracted into ether (500 mL)
  3. washwashed with brine (300 mL)
  4. dry with materialdried over MgSO4
  5. concentrationconcentrated in vacuo
  6. customThe resulting brown solid was purified by silica gel chromatography
  7. washeluting with 20% ethyl acetate in hexane

Sources & evidence

ORD record
ord-bb64a1a771c94221adb9685dabd92b1c
Source dataset
uspto-grants-1996_10
Patent number
US05565482

Reaction notes

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