sulfuric acid; acetic anhydride 1.) ice-cooling, 3 h, 2.) 0 deg C, 12 h;

1: 46 percent / potassium tert-butoxide / diethyl ether / 1 h 2: 90 percent / conc. sulfuric acid, acetic anhydride / 1.) ice-cooling, 3 h, 2.) 0 deg C, 12 h View Scheme

T=130°C; 0.5 h;