Flocoumafen → 104563-60-2

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Reaction Steps

An approximately 1:1 mixture of the cis and trans isomers of 1-(4-hydroxycoumarin-3-yl)-3-[4-(4-trifluoromethylbenzyloxy)phenyl]-1,2,3,4-tetrahydronaphthalene in the form of a viscous oil (13.Og) was dissolved in ethanol (250 cm3) at the ambient temperature and the solution kept in an open flask at the ambient temperature for 3 days during which time some of the ethanol evaporated and some precipitation of a solid material occurred. This was collected by filtration and dried to give trans-(4-hydroxycoumarin-3-yl)-3-[4-(4-trifluoromethylbenzyloxy)phenyl]-1,2,3,4-tetrahydronaphthalene (containing 7% by weight of the cis-isomer, 1.5g), melting point 153° -155° C. The filtrate was concentrated by removal of the ethanol by evaporation under reduced pressure. The residual oil was then dissolved in boiling ethanol (100cm3) and the solution allowed to cool to 35° to 40° C. and maintained at this temperature whilst a precipitate formed rapidly. This was collected by filtration and dried to give cis-1 -(4-hydroxycoumarin-3-yl) -3-[4-(4-trifluoromethylbenzyloxy)phenyl]1,2,3,4 -tetra-hydronaphthalene (containing 5% by weight of the trans-isomer, 5.5g) melting point 183° -184° C.

Provenance & Evidence