Tetrahedron letters

A simple and efficient synthesis of 2-alkylazulenes

N Iwama, M Kashimoto, H Ohtaki, T Kato, T Sugano

Index: Iwama, Naoshi; Kashimoto, Masami; Ohtaki, Hisashi; Kato, Taku; Sugano, Toshihiko Tetrahedron Letters, 2004 , vol. 45, # 50 p. 9211 - 9213

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Citation Number: 6

Abstract

The annulation method based on 2H-cyclohepta [b] furan-2-ones was applied for the synthesis of 2-alkylazulenes; 2-R-azulene (R= Et, i-Pr, n-Pr, i-Bu). Tropolone p- toluenesulfonate was used as a starting compound. By the two step synthesis, 1-carboxylic- 3-cyanoazulene derivatives were obtained. Treatment of 1-carboxylic-3-cyanoazulene derivatives with aq H2SO4 resulted in decarboxylation and elimination of cyano group to ...