Hydrochloric Acid → 6-Methoxythianaphthen-2-one

HRID 850720Notes

Reaction equation

HRID 850720 reaction equation
CN(C)[C:3]1[S:7][C:6]2[CH:8]=[C:9]([O:12][CH3:13])[CH:10]=[CH:11][C:5]=2[CH:4]=1.Cl.[O:16]1CCCC1>>[CH3:13][O:12][C:9]1[CH:10]=[CH:11][C:5]2[CH2:4][C:3]([S:7][C:6]=2[CH:8]=1)=[O:16]

Participants

4

Reactant 3

HCID 313Hydrochloric AcidHCID 8028TetrahydrofuranHCID 10512530Benzo[b]thiophen-2-amine, 6-methoxy-N,N-dimethyl-

Product 1

HCID 154582606-Methoxythianaphthen-2-oneYield 80%

Procedure

To tetrahydrofuran (200 ml) containing 2-dimethylamino-6-methoxybenzo[b] thiophene (20.00 g, 96.5 mmol) is added 1N aqueous hydrochloric acid (200 ml) and the resulting mixture is heated to reflux for 3 hours. The mixture is cooled, the layers are separated, and the aqueous layer is extracted with methylene chloride (300 ml). The combined organic layers washed with water (250 ml), dried over magnesium sulfate, filtered and concentrated to give crude product, which is recrystallized from ethanol, and dried in vacuo at room temperature to afford the title compound (13.89 g, 77.0 mmol, 80%): mp 80-82° C.; IR (KBr) 1713, 1605, 1485, 1287, 1015, 865, 813 cm-1 ; 1H NMR (DMSO-d6) δ7.22 (d, 1 H, J=8.4 Hz), 7.11 (s, 1 H), 6.78 (d, 1 H, J=8.4 Hz), 4.06 (s, 2 H), 3.71 (s, 3 H); 13C NMR (DMSO-d6) d 203.5, 159.0, 136.9, 125.6, 124.6, 112.3, 108.4, 55.3, 46.2. Anal. Calcd. for C9H8O2S: C, 59.98; H, 4.47; S, 17.78. Found: C, 60.19; H, 4.57; S, 18.03.

Workup

  1. temperaturethe resulting mixture is heated
  2. temperatureto reflux for 3 hours
  3. temperatureThe mixture is cooled
  4. customthe layers are separated
  5. extractionthe aqueous layer is extracted with methylene chloride (300 ml)
  6. washThe combined organic layers washed with water (250 ml)
  7. dry with materialdried over magnesium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated
  10. customto give crude product, which
  11. customis recrystallized from ethanol
  12. customdried in vacuo at room temperature

Sources & evidence

ORD record
ord-4d8312f28bd141b78161c90bd9c0b561
Source dataset
uspto-grants-2000_01
Patent number
US06018056

Reaction notes

Loading…