Toluene → 5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-one

HRID 1615514Notes

Reaction equation

HRID 1615514 reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[CH2:6][CH2:7][CH2:8][CH2:9][C:10]([OH:12])=O.O=P12OP3(OP(OP(O3)(O1)=O)(=O)O2)=O.C1(C)C=CC=CC=1>>[S:1]1[CH:5]=[CH:4][C:3]2[C:10](=[O:12])[CH2:9][CH2:8][CH2:7][CH2:6][C:2]1=2

Participants

4

Reactant 3

HCID 1140TolueneHCID 14812Phosphorus oxide (P4O10)HCID 1523245-(2-Thienyl)valeric acid

Product 1

HCID 123415575,6,7,8-tetrahydro-4H-cyclohepta[b]thiophen-4-oneYield 75.2%

Procedure

A mixture of 5-(2-thienyl)pentanoic acid (8.9 g, 48.0 mmol), phosphorus pentoxide (24.7 g, 86.9 mmol) and celite (16.0 g) in toluene (338 mL, 3170 mmol) was heated to reflux for 2 hr. The resulting black mixture was allowed to cool to rt and filtered. The solid cake was washed thoroughly with ethyl acetate then the filtrate was washed with saturated NaHCO3, dried over MgSO4, concentrated and dried under high vacuum to afford 6.0 g product as a brown oil (74.0% yield). LCMS: (FA) ES+ , 167. 1H NMR (400 MHz, CDCl3) δ: 7.40-7.42 (d, J=5.3, 2H), 6.98-7.00 (d, J=5.3, 2H), 3.0-3.12 (m, 2H), 2.72-2.76 (m, 2H), 1.85-2.0 (m, 4H).

Workup

  1. temperaturewas heated
  2. temperatureto reflux for 2 hr
  3. filtrationfiltered
  4. washThe solid cake was washed thoroughly with ethyl acetate
  5. washthe filtrate was washed with saturated NaHCO3
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated
  8. customdried under high vacuum

Sources & evidence

ORD record
ord-0798370ebaa94f7c89c634fcd962e6a1
Source dataset
uspto-grants-2014_07
Patent number
US08765746B2

Reaction notes

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