Sodium Bicarbonate → KB-5492 free base

Beteiligte Stoffe

Reaktionsschritte

A mixture of 1-(3,4,5-trimethoxybenzyl)piperazine dihydrochloride (prepared by the method disclosed in Belgian Pat. No. 560,330) (50 g), 4-methoxyphenyl chloroacetate (prepared by the method disclosed in U.S. Pat. No. 3,657,318) (33 g), sodium hydrogen carbonate (49 g) and acetonitrile (700 ml) is stirred at 60° C. for 3 hours. The reaction mixture is filtered, and the filtrate is concentrated under reduced pressure to give crude 1-[(4-methoxyphenoxy)carbonylmethyl]-4-(3,4,5-trimethoxybenzyl)piperazine (free base) (60 g) as an oily substance. This crude free base (60 g) is dissolved in a mixture of water (200 ml) and acetonitrile (50 ml) and thereto is added fumaric acid of about 2 moles (41 g) to 1 mole of the free base, and the mixture is heated. After the reaction mixture is allowed to cool at room temperature, the precipitated crystals are separated by filtration and recrystallized from a mixture of water and acetonitrile to give 1-[(4-methoxyphenoxy)carbonylmethyl]-4-(3,4,5-trimethoxybenzyl)piperazine difumarate monohydrate (73.5 g) as colorless crystals.

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