4-Carboxyphenyl trifluoromethanesulfonate (0.40 g, 1.5 mmol; described in: Looker, J. H.; Hayes, C. H.; Thatcher, D. N. J. Am. Chem. Soc. 1957, 79, 741-4) was dissolved in thionyl chloride (10 mL) and heated at 40° C. for 45 min. The excess of thionyl chloride was evaporated in vacuo, the residue was treated with toluene and again the solvent was removed in vacuo. The crude acid chloride (280 mg, 0.96 mmol) was dissolved in methylene chloride (5 mL) and added dropwise to an ice-cooled solution of (R)-2-amino-8-(4-methylpiperazin-1-yl)-1,2,3,4-tetrahydronaphthalene (110 mg, 0.46 mmol) and triethylarine (96 μL, 0.69 mmol) in methylene chloride (20 mL). After the addition the reaction was allowed to stir at ambient temperature for 15 min and then washed with water. The phases were separated and the combined organic phases were dried (Na2SO4), filtered and evaporated in vacuo to give a crude product which was purified on a silica gel column using chloroform/ethanol saturated with NH3 (100:3) as the eluent. Yield: 100 mg (44%) of the title compound as white crystals: mp 178-180° C.; [α]21D −31° (c 1.0, chloroform); EIMS (70 eV) m/z (relative intensity) 497 (17, M+).
