[CH2:1]([O:3][C:4](=[O:16])[C:5]1[CH:10]=[C:9]([CH3:11])[C:8]([CH:12]=[C:13]([CH3:15])[CH3:14])=[N:7][CH:6]=1)[CH3:2]>C1COCC1.CO.[Pd]>[CH2:1]([O:3][C:4](=[O:16])[C:5]1[CH:10]=[C:9]([CH3:11])[C:8]([CH2:12][CH:13]([CH3:15])[CH3:14])=[N:7][CH:6]=1)[CH3:2]5-Methyl-6-(2-methyl-propenyl)-nicotinic acid ethyl ester (3.98 g, 18.2 mmol) is dissolved in THF (100 mL) and methanol (100 mL), Pd/C (500 mg, 10% Pd) is added and the mixture is stirred under 1 atm H2 at rt for 15 h. The catalyst is filtered off and the filtrate is evaporated to give 6-isobutyl-5-methyl-nicotinic acid ethyl ester (3.76 g) as a colourless oil; LC-MS: tR=0.75 min; [M+1]+=222.15; 1H NMR (CDCl3) δ 0.97 (d, J=6.8 Hz, 6H), 1.42 (t, J=7.3 Hz, 3H), 2.20 (hept, J=6.8 Hz, 1H), 2.38 (s, 3H), 2.75 (d, J=7.0 Hz, 2H), 4.41 (q, J=7.3 Hz, 2H), 8.03 (d, J=1.8 Hz, 1H), 9.00 (d, J=2.0 Hz, 1H).
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