Ethanol → 4-Ethyl-2,4-hexadien-1-ylamine

A mixture of N-(4-ethyl-2,4-hexadien-1-yl)phthalimide (5.0 g), hydrazine monohydrate (2.45 g), and ethanol (150 ml) was refluxed for 1.5 hours under nitrogen atmosphere. After cooling, the precipitate was filtered and washed with ethanol. Evaporation of the filtrate gave a crystalline residue which was dissolved in 1N sodium hydroxide solution and extracted with dichloromethane. The organic extract was washed with water and brine, dried over anhydrous sodium sulfate, and evaporated to give crude 4-ethyl-2,4-hexadien-1-ylamine (2.59 g) as an oil. The crude oil was dissolved in dichloromethane (30 ml) containing triethylamine (6.28 g). To this solution cooled to 0° C. was added nicotinic acid chloride hydrochloride (3.41 g) in small portions during 10 minutes. After 30 minutes, triethylamine (4.19 g) and nicotinic acid chloride hydrochloride (0.79 g) were added and the mixture was stirred for 30 minutes at 0° C. The reaction mixture was diluted with dichloromethane, washed with water and brine, dried over anhydrous magnesium sulfate, and evaporated in vacuo. The residue was chromatographed on silica gel (2% methanol-dichloro-methane) to give a mixture of N-[(2E,4E) and (2Z,4E)-4-ethyl-2,4-hexadien-1-yl]-3-pyridinecarboxamide (4.6 g) which crystallized on standing.