2-Chloro-3-(2,3-epoxy-propoxy)-pyrazine → 1-{1-[2-Hydroxy-3-(3-chloro-pyrazin-2-yloxy)-propyl]-4-piperidinyl}-3-phenylimidazolidin-2-one

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Reaction Steps

7.27 g of 2-chloro-3-(2,3-epoxy-propoxy)-pyrazine and 7.35 g of 1-(4-piperidyl)-3-phenyl-2-imidazolidinone in 120 ml of isopropanol are stirred for 24 hours at approx. 20° C. The reaction mixture is then concentrated in a water jet vacuum. The residue crystallises from ether and yields 1-{1-[2-hydroxy-3-(3-chloro-pyrazin-2-yloxy)-propyl]-4-piperidinyl}-3-phenylimidazolidin-2-one with a melting point of 122°-124° C. The starting material can be prepared as follows: 9.8 g of N-phenylethylenediamine and 13.9 g of 1-benzyl-4-piperidone are dissolved in 200 ml of methanol and, with the addition of 0.7 g of a 5% platinum on charcoal catalyst, hydrogenated at room temperature and under normal pressure. The calculated amount of hydrogen is taken up after approx. 3 hours. The reaction mixture is filtered to remove the catalyst and concentrated in a water jet vacuum. The residue crystallises from methanol/water to yield 21.4 g of 1-benzyl-4-(2-phenylamino-ethylamino)-piperidino with a melting point of 78°-81° C.

Provenance & Evidence