Ammonia → 4-Ethinyl-2-(p-methoxybenzyl)-1,3,3-trimethyl-4-piperidinol

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Reaction Steps

A stream of acetylene, after successively having been washed with water, cooled to -80° C and dried with CaCl2, is led into a mechanically stirred solution of 7 g of lithium in 750 ml of dry liquid ammonia which is cooled at about -50° C. After about 5 hours the blue colour disappears. To the solution of acetylene lithium so obtained there is added dropwise 60 g of 2-(p-methoxybenzyl)-1,3,3-trimethyl-4-piperidone dissolved in 250 ml of absolute ether. During the addition a slow stream of acetylene is maintained, but afterwards this is stopped and the reaction mixture is stirred for 16 hours, the ammonia being allowed to evaporate gradually. The resulting suspension is diluted by addition of 250 ml of absolute ether and stirred for another 2 hours at 30° C. After cooling 54 g of ammonium chloride and water are added. The reaction product is secured from the organic layer in the usual manner. It is recrystallized from a mixture of benzene and petroleum ether. Yield 88%. Melting point 103°-110° C.

Provenance & Evidence