A mixture of 5-methoxy-8-nitro-1,2,3,4-tetrahydronaphthalene-2-carboxylic acid (1.0 g, 4 mmol), toluene (20 mL), N,N-dimethylformamide (10 drops) and thionyl chloride (1.5 mL, 20 mmol) was heated at 60° C. for 1 h. The solvents were removed in vacuo and the residue, dissolved in methylene chloride (20 mL), was added to a solution of 4-aminobenzoylmorpholine (820 mg, 4 mmol, described in: Deylin J. P. J. Chem. Soc. Perkin Trans I, 1975, 830-841) and triethylamine (800 mg, 8 mmol) in methylene chloride (30 mL) at 5° C. After stirring at 20° C. for 2 h, water was added and the organic phase was separated, dried and the solvent removed in vacuo. The oily residue was crystallized from diisopropyl ether/ethyl acetate affording 1.2 g (73% yield) of the title compound as crystals: mp 186-189° C.; EIMS (70 eV) m/z (relative intensity) 439 (20, M+).
