Synthesis of 8-methoxycoumarin-3-carboxamides (4–7) and 8-methoxycoumarin-3-carboxylic acid derivatives (8,9). Reagents and reaction conditions: a diethylmalonate, piperidine, fusion, 2 h; b Bromine, AcOH, 60 °C, 8 h; c Ammonium acetate, fusion, 6 h; d Acetic anhydride, reflux, 12 h; e acetic acid, 4N HCl, reflux, 16 h