2-Thiophenecarboxylic acid → 5-Chloromethyl-2-thienylcarboxylic acid

HRID 442347

Reaktionsgleichung

Reaktionsgleichung von HRID 442347
[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]=1

Komponenten

5

Edukt 3

HCID 107002-Thiophenecarboxylic acidHCID 10967Bis(Chloromethyl) EtherHCID 6451240Aluminum(III) Chloride

Produkt 1

HCID 227677545-Chloromethyl-2-thienylcarboxylic acid

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6212ChloroformLösungsmittel

Versuchsvorschrift

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 the obtained acid with excess thionyl chloride at room temperature for about 16 hours 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 acetate is hydrolyzed by treatment of a 1:1 mixture of acetic acid and concentrated hydrochloric acid at room temperature overnight to give 5-chloromethyl-2-thienylacetic acid.

Quellen und Nachweise

ORD-Eintrag
ord-dd3d26a8cb0b4223bd1bcc56778efab6
Quelldatensatz
uspto-grants-1977_08
Patentnummer
US04045438

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