反应条件
1.1: potassium carbonate / N,N-dimethyl-formamide / 1 h / 25 - 85 °C 1.2: 20 h 2.1: water; hydrogen bromide / 4 h / 90 - 95 °C 2.2: 25 - 30 °C / pH 2.8 3.1: triethylamine; tetrabutylammomium bromide / ethyl acetate; N,N-dimethyl-formamide / 1 h / 25 - 35 °C 3.2: 25 - 35 °C View Scheme