potassium hydroxide; orthoformic acid triethyl ester; benzoic acid 1.) 70-80 deg C, 1 h 2.) 170 deg C, 4 h 3.) reflux, 8 h;

1: 200 mg / ethylorthoformate/benzoic acid, 3.) alc. KOH / 1.) 70-80 deg C, 1 h 2.) 170 deg C, 4 h 3.) reflux, 8 h 2: 100 mg / pyridine / 1 h / Heating View Scheme