To a solution of N-[2,2-diethoxy-2-(2-isobutyl-6-methyl-pyridin-4-yl)-ethyl]-2,6-dimethyl-isonicotinamide (60 mg, 0.177 mmol) in THF (4 mL), 25% aq. HCl (50 μL) is added and the mixture is stirred at 65° C. for 2 h. Another portion of 25% aq. HCl (50 μL) is added and stirring is continued at 65° C. for 3 h. The mixture is cooled to 0° C., neutralized by adding 1 N aq. NaOH solution and extracted twice with EA. The combined org. extracts are dried over Na2SO4, filtered and concentrated to give crude N-[2-(2-isobutyl-6-methyl-pyridin-4-yl)-2-oxo-ethyl]-2,6-dimethyl-isonicotinamide (48 mg) as an orange oil. Part of this material (22 mg) is purified on prep. TLC plates using DCM containing 10% of methanol to give N-[2-(2-isobutyl-6-methyl-pyridin-4-yl)-2-oxo-ethyl]-2,6-dimethyl-isonicotinamide (9 mg) as a pale yellow oil; LC-MS: tR=0.75*, [M+1]+=330.13; 1H NMR (CDCl3): δ 0.97 (d, J=6.5 Hz, 6H), 2.09-2.21 (m, 1H), 2.64 (s, 6H), 2.67 (s, 3H), 2.75 (d, J=7.3 Hz, 2H), 4.94 (d, J=3.8 Hz, 2H), 7.23 (s br, 1H), 7.38 (s, 2H), 7.42 (s, 1H), 7.49 (s, 1H).
