Benzofurans. Improved syntheses of bufuralol, 7-ethyl-2-(2-<i>tert</i>-butylamino-1-hydroxyethyl)benzofuran, and 1″-oxobufuralol, 7-acetyl-2-(2-<i>tert</i>-butylamino-1-hydroxyethyl)benzofuran
作者:S. Ananda Weerawarna、Michael Guha-Biswas、Wendel L. Nelson
DOI:10.1002/jhet.5570280535
日期:1991.8
An improved laboratory scale synthesis of bufuralol (1) and 1″-oxobufuralol (4) was accomplished. The intermediate benzofurans were prepared via aromatization of 2,3-dihydrobenzofurans or by a one-step acidcatalyzed cyclization from 2,2-diethoxyethyl 4-bromo-6-ethyl-2-formylphenyl ether (23). Base-catalyzed cyclization of 3-(5-bromo-3-ethyl-2-hydroxyphenyl)-1.2-epoxypropane (16) provided the key intermediate