1: 2,5-dimethoxy-benzoic acid With lithium; diethylamine in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide T=10 - 15°C; ultrasonic irradiation; 2: n-dodecyl iodide in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide 1 h; 3: With hydrogenchloride in N,N,N',N',N'',N''-hexamethylphosphoric triamide; water pH=1; 2.5 h; Heating;