Synthesis 2018; 50(09): 1891-1900
DOI: 10.1055/s-0036-1591905
paper
© Georg Thieme Verlag Stuttgart · New York

Expeditious Scalable Catalyst-Free One-Pot Synthesis of 4-Alkoxy-5-amino-3-methylthiophene-2-carbonitriles via Sequential Reactions­ of Lithiated Alkoxyallenes with Isothiocyanates and 2-Bromoacetonitrile

Nina A. Nedolya*
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Favorsky Street 1, 664033 Irkutsk, Russian Federation   Email: nina@irioch.irk.ru   Email: boris_trofimov@irioch.irk.ru
,
Olga A. Tarasova
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Favorsky Street 1, 664033 Irkutsk, Russian Federation   Email: nina@irioch.irk.ru   Email: boris_trofimov@irioch.irk.ru
,
Alexander I. Albanov
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Favorsky Street 1, 664033 Irkutsk, Russian Federation   Email: nina@irioch.irk.ru   Email: boris_trofimov@irioch.irk.ru
,
Boris A. Trofimov*
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Favorsky Street 1, 664033 Irkutsk, Russian Federation   Email: nina@irioch.irk.ru   Email: boris_trofimov@irioch.irk.ru
› Author Affiliations

This work was made possible through financial support from the Russian Foundation for Basic Research (Grant No. 16-03-00234a).
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Publication History

Received: 22 November 2017

Accepted after revision: 26 December 2017

Publication Date:
29 January 2018 (online)


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Abstract

A synthetically simple and convenient approach to tetrasubstituted thiophenes with rare combination of the alkoxy, amino, and cyano groups has been developed. The assembly of polyfunctionalized thiophene ring is implemented in one preparative step by sequential addition of isothiocyanate and 2-bromoacetonitrile to the lithiated (with n-BuLi) alkoxyallene. The reaction proceeds through in situ formation and intramolecular cyclization of cyanomethyl 2-alkoxy-N-buta-2,3-dienimidothioate (1-aza-1,3,4-triene).

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