CO[C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([O:9][CH3:10])[C:4]=1/[CH:11]=[N:12]/[CH:13]([CH:17]([CH3:19])[CH3:18])[CH:14]([CH3:16])[CH3:15].[CH2:20]([Li])[CH3:21]>C1COCC1.C1CCCCC1.C1C=CC=CC=1>[CH2:20]([C:3]1[CH:8]=[CH:7][CH:6]=[C:5]([O:9][CH3:10])[C:4]=1/[CH:11]=[N:12]/[CH:13]([CH:17]([CH3:19])[CH3:18])[CH:14]([CH3:16])[CH3:15])[CH3:21]To a solution of 10.0 g (38 mmol) [1-(2,6-dimethoxy-phenyl)-meth-(E)-ylidene]-(1-isopropyl-2-methyl-propyl)-amine in 30 ml dry THF cooled to −20° C. were added 91.2 ml of a 0.5M solution of ethyl lithium in cyclohexane/benzene drop-wise to keep temperature below 0° C. Then the mixture was stirred at −20° C. for further 30 min and the reaction quenched by addition of water. The aqueous phase was extracted with ethyl acetate, the combined extracts washed with brine, dried over Na2SO4, filtered and evaporated. Purification of the crude product by flash chromatography on silica gel with a heptane/ethyl acetate gradient provided 4.30 g (E)-[1-(2-ethyl-6-methoxy-phenyl)-methylidene]-(1-isopropyl-2-methyl-propyl)-amine as colourless liquid: MS (EI): 261.4 (M+.), 218.3 ((M-((CH3)2CH)+.), 100%).
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