Collect. Czech. Chem. Commun.
1991, 56, 991-1010
https://doi.org/10.1135/cccc19910991
Unusual reactions of guaiazulene with N-bromosuccinimide and synthesis of variously functionalized azulenes using these reactions
Tetsuo Nozoea, Kimio Shindob, Hidetsugu Wakabayashic, Teruo Kuriharab and Sumio Ishikawab
a Tokyo Research Laboratories, Kao Corporation, 2-1-3 Bunka, Sumida-ku, Tokyo 131, Japan
b Department of Chemistry, Faculty of Science, Josai University, 1-1 Keyakidai, Sakado-shi, Saitama-ken 350-02, Japan
c Department of Chemistry, Faculty of Science, Josai University. 1-1 Keyakidai, Sakado-shi, Saitama-ken 350-02, Japan
Abstract
Treatment of guaiazulene (Ia) with NBS in benzene gives various, side-chain-brominated compounds, but in hexane it affords exclusively 3-bromoguaiazulene (Id). Compound Id is stable in hexane at 5°C in the absence of oxygen, whereas in benzene it changes very rapidly to a mixture of similar compounds as those directly obtained from Ia and NBS in benzene. Possible pathways for the formation of these compounds are briefly discussed. By utilizing these reactions, various kinds of side-chain functionalized azulenes that are otherwise not available by conventional methods can be readily prepared from Ia.
