Figure 2. Reagents and conditions: i) phenol, potassium tert-butoxide, Cu, DMF, reflux, 5 h; ii) H₂SO₄, EtOH, reflux, 24 h; iii) NH₂NH₂.H₂O, EtOH, rt, 12 h; iv) ethylchloroglyoxylate, triethylamine, THF, 0°C, 3 h; v) P₂O₅, toluene, reflux, 3 h; vi) proper amine, AlCl₃, DCM, rt, 3-24h.