反应详情

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11 mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly a solution of tetramethylpyrazine (13.6 g, 0.1 mole) in 100 mL of tetrahydrofuran. The mixture is allowed to warm to room temperature and then cooled to -78° C. A solution of α-hexylcinnamaldehyde (23.7 g, 0.11 mole) in 100 mL of tetrahydrofuran is added dropwise over 15 minutes. The solution is allowed to warm to room temperature, and then poured into an ice/dilute hydrochloric acid mixture. The organic layer is separated and washed with saturated solutions of sodium bicarbonate and sodium chloride. The solution is dried over anhydrous magnesium sulfate. After filtration of drying agent and evaporation of solvent, a yield of 40 g of crude material is obtained. A volatile fraction in the crude material is removed by distillation at below 85° C. under 0.15 torr of mercury. The residue is crystallized from a mixture of ethyl acetate-hexane. The product is obtained as a fine needle, M.P. 61°-62° C. Yield 26 g (70%). NMR and IR confirm the structure.

1. temperaturecooled to -78° C
2. temperatureto warm to room temperature
3. customThe organic layer is separated
4. washwashed with saturated solutions of sodium bicarbonate and sodium chloride
5. dry with materialThe solution is dried over anhydrous magnesium sulfate
6. filtrationAfter filtration
7. customof drying
8. customagent and evaporation of solvent