Hydrochloric Acid → 3,4-dihydro-1-(4-piperidinyl)-2(1H)-Quinazolinone

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Reaction Conditions

Reaction Steps

In this reference example, 16.0 g of 1-benzyl-4-[3,5-dihydro-2(1H)-quinazolinon-1-yl]-piperidine, 4.0 g of 10% Pd-C, 50 ml of 1 N hydrochloric acid, 150 ml of water and 300 ml of methanol are mixed and stirred at 40° C. Hydrogen gas is introduced to the mixture for 5 hours with stirring. Then, the Pd-C is removed by filtration and the filtrate is concentrated. The white crystalline residue is dissolved in 50 ml of water. The solution is adjusted to pH 10 with aqueous 5 N sodium hydroxide and extracted with chloroform. The extract is washed with water, dried and thereafter concentrated. Then, 50 ml of a mixture of ethyl acetate and n-hexane (1:1 by volume) is added to the residue. After trituration, the solid is separated by filtration, washed with the same mixed solvent to obtain 9.9 g of a crude product. The crude product is recrystallized from water-ethanol to obtain 5.1 g of the desired product.

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