Download PDF
Synthesis 2007(3): 452-456  
DOI: 10.1055/s-2006-958975
PAPER
© Georg Thieme Verlag Stuttgart · New York

Selective Thiylation of 1-Vinylpyrrole-2-carbaldehydes: Synthesis of the Novel Pyrrole Synthons 2-[Bis(ethylsulfanyl)methyl]-1-vinylpyrroles and 1-(2-Ethylthioethyl)pyrrole-2-carbaldehydes

Alexander M. Vasil’tsov, Andrey V. Ivanov, Igor’ A. Ushakov, Al’bina I. Mikhaleva, Boris A. Trofimov*
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky Street, 664033 Irkutsk, Russian Federation
Fax: +7(3952)419346; e-Mail: boris_trofimov@irioch.irk.ru;
Further Information

Publication History

Received 25 September 2006
Publication Date:
08 January 2007 (online)

    Permissions and Reprints All articles of this category

Abstract

1-Vinylpyrrole-2-carbaldehydes have been selectively thiylated with ethanethiol either at the aldehyde (acid catalysis) or at the N-vinyl group (free-radical initiation) to afford 1-vinylpyrrole-2-carbaldehyde thioacetals (88-99% yield) or 1-(2-ethylthio­ethyl)pyrrole-2-carbaldehydes (68-89% yield), respectively. Both derivatives constitute important new families of pyrrole building blocks. Exhaustive thiylation at both the aldehyde and vinyl functionalities was achieved by acid-catalyzed reaction of the ethylthioethyl derivative of pyrrole-2-carbaldehyde with ethane thiol. An unexpected reduction of the ethylthioacetal group by ethanethiol to give the ethylthiomethyl group under free-radical initiation was also observed and is discussed.

Key words

1-vinylpyrrole-2-carbaldehydes - ethanethiol - thiylation - thioacetals - sulfides - radical initiation - acid catalysis