2-Thiophenecarboxylic acid → 5-Chloromethyl-2-thienylcarboxylic acid
Reaction equation
[S:1]1[CH:5]=[CH:4][CH:3]=[C:2]1[C:6]([OH:8])=[O:7].[Cl:9][CH2:10]OCCl.[Cl-].[Al+3].[Cl-].[Cl-]>C(Cl)(Cl)Cl>[Cl:9][CH2:10][C:5]1[S:1][C:2]([C:6]([OH:8])=[O:7])=[CH:3][CH:4]=1Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
2-Thiophenecarboxylic acid is treated in a solution of chloroform with chloromethyl ether in the presence of 0.9 to 2.2 equivalents of aluminum chloride to give 5-chloromethyl-2-thienylcarboxylic acid. Treatment of theobtained acid with excess thionyl chloride at room temperature for about 16hours yields the acid chloride which is reacted with diazomethane to give the corresponding diazoketone. A methanol solution of the diazoketone is irradiated under nitrogen for about one hour with a high pressure mercury lamp using a Quarz filter. The methyl 5-chloromethyl-2-thienylacetate is obtained upon work up and column chromatography on silica gel. The acetateis hydrolyzed by treatment of a 1:1 mixture of acetic acid and concentratedhydrochloric acid at room temperature overnight to give 5-chloromethyl-2-thienylacetic acid.
Sources & evidence
- ORD record
- ord-b53122e7f32141ddb70a87a0ab4ed3c0
- Source dataset
- uspto-grants-1977_05
- Patent number
- US04026887
Reaction notes
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