Hydrochloric Acid → trans 2-[4-(1-Oxo-3-phenyl-2-propenyl)-1-piperazinyl]-4,5,6-trimethoxy-1-indanol

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Reaction Steps

A mixture of 3.3 g (11 mmole) of 2-bromo-4,5,6-trimethoxy-1-indanone (Haworth et al., J. Chem. Soc. 1952 1583-1588), 2.16 g (10 mmole) of 1-(1-oxo-3-phenyl-2-propenyl)-piperazine, 0.92 g (11 mmole) of NaHCO3 in 8 ml of methanol is refluxed with stirring for 16 hours. After cooling, and maintaining the temperature at 0°-5° C., 0.77 g (20 mmole) of NaBH4 are added at portions, then the mixture is allowed to stand for 4 hours at room temperature under stirring. The mixture is cooled and made acidic by the addition of 15% aqueous HCl. After concentration under reduced pressure, the mixture is made alkaline by the addition of an aqueous 5% solution of sodium carbonate and extracted with methylene dichloride. The organic phase is washed with H2O to neutrality and dried over sodium sulfate. On evaporation under reduced pressure, 4.2 g are obtained as a mixture of diastereoisomers cis/trans which are separated by flash-chromatography through a column filled with silicagel 60 Merck 230-400 mesh, using chloroform:acetone 50:50 as the eluent. After crystallization from acetone, 1,2 g of cis-isomer are obtained (yield 27.4%), m.p. 162-163° C. On cristallization from acetone, 1.25 g of trans-isomer are obtained (yield 28.5%); m.p. 168°-170° C.

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