Piperazine, hexahydrate → 1-(6-Hydroxy-2,2-dimethyl-1,3-dioxepan-5-yl)-piperazine

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Reaction Steps

14.4 g (0.1 mol) of 4,4-dimethyl-3,5,8-trioxabicyclo[5.1.0]octane (J. Org. Chem. 41, 2469 [1976]) are heated under reflux in 100 ml of acetonitrile with 20 g (0.1 mol) of piperazine hexahydrate for 8 hours and the 1,4-bis-(6-hydroxy-2,2-dimethyl-1,3-dioxepan-5-yl)-piperazine precipitated [melting point: 235°-237° (from isopropanol)] is filtered off with suction. The mother liquor is concentrated and the residue is purified by chromatography on 200 g of silica gel with methylene chloride/methanol (9:1) as the mobile phase, the main component being eluted towards the end of the chromatography with methylene chloride/methanol (4:1). 4.7 g of 1-(6-hydroxy-2,2-dimethyl-1,3-dioxepan-5-yl)-piperazine are obtained as an oil; Rf value=0.05 (on silica gel; methylene chloride/methanol (9:1)].

Provenance & Evidence