A mixture of 2-chloro-4-phenyl-3-(1H-tetrazol-5-yl)-6-trifluoromethyl-quinoline (105 mg, 279 μmol), piperidine (47.6 mg, 55.3 μl, 559 μmol) and triethylamine (84.8 mg, 117 μl, 838 μmol) in DMA (2 ml) was heated to 100° C. in a sealed tube. After 4 h 0.1N HCl was added at room temperature and the mixture was extracted with EtOAc. The combined organic layers were washed with 0.1N HCl and brine and dried with Na2SO4. The remaining brown oil was purified by chromatography (silica gel, DCM/MeOH 98:2 to 95:5). The product fractions were concentrated and the remaining solid was dissolved in EtOAc, filtered through silica gel and evaporated. The remaining residue was finally purified by preparative thin-layer chromatography (DCM/MeOH 95:5) to obtain the title compound (22 mg, 18%) as light yellow solid. MS (ESI): 425.4 (M+H)+.
