Direct Bromination of Ethyl
5-Alkylthiophene-2-carboxylates

Ilya V. Taydakov; Sergey S. Krasnoselskiy

doi:10.1055/s-0030-1258160

PAPER

Direct Bromination of Ethyl 5-Alkylthiophene-2-carboxylates

Ilya V. Taydakov*^a, Sergey S. Krasnoselskiy^b
^a G. S. Petrov Institute of Plastics, JSC, Perovskiy proezd 35, Moscow 111024, Russian Federation
Fax: +7(495)6000603; e-Mail: taidakov@gmail.com;
^b People’s Friendship University of Russia, Miklukho-Maklaya str. 9, Moscow 117198, Russian Federation

Abstract

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Abstract

Approaches to brominated thiophene-2-carboxylic acids by electrophilic bromination of the corresponding acids and esters were compared and investigated. A synthetic route was developed involving direct bromination of ethyl 5-alkylthiophene-2-carboxylates followed by saponification of the resulting ethyl 5-alkyl-4-bromothiophene-2-carboxylates. The key bromination step is selective in dichloromethane solution at 0-5 ˚C and furnishes the corresponding ethyl 5-alkyl-4-bromothiophene-2-carboxylates in excellent yields. No migration or isomerization of the alkyl substituents was observed.

Key words

bromine - esters - thiophenes - electrophilic aromatic substitutions - aluminum

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References

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