potassium carbonate in N,N-dimethyl-formamide T=20°C; 18 h;

in chloroform 3 h; Ambient temperature;

1: 50 percent aq. H2SO4 / 3 h / 80 °C 2: H2SO4 / 16 h / Heating View Scheme

sulfuric acid T=80°C; 3 h;

sodium hydroxide 1) water, 30 min, reflux, 2) 95percent ethanol, 20 min, reflux, 3) HCl;

1: 64 percent / 50percent NaOH / 1) water, 30 min, reflux, 2) 95percent ethanol, 20 min, reflux, 3) HCl 2: 97 percent / polyphosphoric acid / 16 h / 80 °C 3: 1) oxalyl chloride / 1) toluene, 60 deg C, 4.5 h, 2) dichloromethane, -60 deg C to room temperature 4: 62 percent / anhydrous hydrazine / 16 h / Ambient temperature View Scheme