Water → HCID 20260914, compound
Reaction equation
C([C:4]1[CH:5]=[CH:6][C:7]2[C:11]([Br:12])=[C:10]([CH3:13])[S:9][C:8]=2[CH:14]=1)(=O)C.[S].N1[CH2:21][CH2:20][O:19]CC1.[OH2:22]>>[Br:12][C:11]1[C:7]2[CH:6]=[CH:5][C:4]([CH2:21][C:20]([OH:19])=[O:22])=[CH:14][C:8]=2[S:9][C:10]=1[CH3:13]Participants
Procedure
A mixture of 6-acetyl-3-bromo-2-methylbenzo[b]thiophene (12.0 g.), sulphur (3.0 g.) and morpholine (12 ml.) was heated under reflux for 6 hours. (This is the Willgerodt-Kindler reaction.) The mixture was poured into water and the resulting green solid was filtered off, washed with water and added to a solution of sodium hydroxide (12.0 g.) in methanol (250 ml.). The mixture was heated under reflux for 6.5 hours and then evaporated. The residue was dissolved in water and the solution was washed with ethyl acetate. The aqueous layer was acidified to give a solid which was filtered off, washed with water and dried to give 3-bromo-6-carboxymethyl-2-methylbenzo[b]thiophene (8.22 g.) pure enough for further reaction. A portion crystallized from toluene/petrol (b.p. 60°-80°) had m.p. 150°-152° C.
Workup
- temperaturewas heated
- temperatureunder reflux for 6 hours
- customthe Willgerodt-Kindler reaction
- filtrationthe resulting green solid was filtered off
- washwashed with water
- additionadded to a solution of sodium hydroxide (12.0 g.) in methanol (250 ml.)
- temperatureThe mixture was heated
- temperatureunder reflux for 6.5 hours
- customevaporated
- dissolutionThe residue was dissolved in water
- washthe solution was washed with ethyl acetate
- customto give a solid which
- filtrationwas filtered off
- washwashed with water
- customdried
Sources & evidence
- ORD record
- ord-f4bf2961aad844cebecb882318421f82
- Source dataset
- uspto-grants-1985_11
- Patent number
- US04551468
Reaction notes
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