Sulfuric Acid → 5,6,7,8-Tetrahydro-1H-benzo[b]cyclopenta[d]thiophen-3(2H)-one

HRID 1024017Notes

Reaction equation

HRID 1024017 reaction equation
Cl[CH2:2][CH2:3][C:4]([C:6]1[S:10][C:9]2[CH2:11][CH2:12][CH2:13][CH2:14][C:8]=2[CH:7]=1)=[O:5].S(=O)(=O)(O)O>>[CH2:2]1[C:7]2[C:8]3[CH2:14][CH2:13][CH2:12][CH2:11][C:9]=3[S:10][C:6]=2[C:4](=[O:5])[CH2:3]1

Participants

3

Reactant 2

HCID 1118Sulfuric AcidHCID 580442963-Chloro-1-(4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)propan-1-one

Product 1

HCID 580437975,6,7,8-Tetrahydro-1H-benzo[b]cyclopenta[d]thiophen-3(2H)-oneYield 47%

Conditions

Temperature
95 °C

Procedure

A 50-mL single-necked round-bottomed flask equipped with a magnetic stirrer was charged with 103b (800 mg, 3.51 mmol) and 98% sulfuric acid (8 mL). After stirring at 95° C. for 16 h, the reaction mixture was poured into ice (50 g), and the resulting suspension was extracted with ethyl acetate (3×50 mL). The organic extracts were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash chromatography to afford 103c in 47% yield (320 mg) as an off-white solid: mp 75-76° C.; 1H NMR (500 MHz, CDCl3) δ 2.89 (m, 2H), 2.87-2.83 (m, 4H), 2.56 (t, 2H, J=6.5 Hz), 1.84 (m, 4H)

Workup

  1. customA 50-mL single-necked round-bottomed flask equipped with a magnetic stirrer
  2. extractionthe resulting suspension was extracted with ethyl acetate (3×50 mL)
  3. dry with materialdried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated under reduced pressure
  6. customThe resulting residue was purified by flash chromatography

Sources & evidence

ORD record
ord-7af6e555611349c5baf1ff55110fe139
Source dataset
uspto-grants-2014_05
Patent number
US08722676B2

Reaction notes

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