Diethyl Ether → 2-(p-Biphenylyl)-3,4-pentadien-2-ol

Beteiligte Stoffe

Reaktionsschritte

To a suspension of 507 g of the crude (foam) methiodide of 2-(p-biphenylyl)-5-dimethylamino-3-pentyn-2-ol obtained by step (b) above, in 4 liters of dry tetrahydrofuran, is added dropwise over a period of one hour, with cooling (to keep at room temperature), 478 g of a solution of sodium dihydrobis (2-methoxyethoxy) aluminate 70% w/w in benzene in 800 ml of dry tetrahydrofuran. The resulting mixture is then stirred at room temperature for 2 hours. The mixture is then cooled to 10° and dropwise there is added 3 liters of 2N sodium hydroxide, with stirring and cooling to 10° to 20°. 10 liters of diethyl ether are then added, in one portion, to the mixture. Solids present (inorganic salts) are removed by filtration on Celite. The filtrate is then extracted twice with 5 liter portions of water, the water washes then being washed three times with 5 liters of diethyl ether each time. The combined ether phases are washed once with 3 liters of aqueous saturated brine solution. The combined organic phases are dried over sodium sulfate, filtered, and the filtrate evaporated by rotary evaporation at 40° to obtain the crude product as an oil. The oil is taken up in 7 liters pentane (heated) and then the resulting pentane solution chilled until a precipitate forms. The precipitate is collected by filtration and washed with pentane. The precipitate is crystallized from pentane five times, then dried in a vacuum oven at room temperature for 12 hours to yield the title product, m.p. 65°-66°.

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