1: 47 mg / pyridine / 22 h / Heating 2: 35 percent / toluene / 1.) reflux, 2 d, 2.) room temp., 1 d, 3.) reflux, 2 d 3: 60 percent / diethyl ether / 7 h 4: 90 mg / acidic alumina / benzene / Heating View Scheme