3.12 g. (8.2 mmoles) of 4,4-dimethyl-9-hydroxy-7-(4-p-fluorophenyl-1-methylbutyl)-1,2,3,4-tetrahydrocyclopenta [c] [1]benzopyran, prepared according to the method of Example 6, 1.77 g. (8.6 mmoles) of dicyclohexylcarbodiimide and 1.65 g. (8.5 mmoles) of β-piperidinopropionic acid hydrochloride (m.p. 216° - 220°, J. Am. Chem. Soc. 73, 3168 (1951) are combined with 125 ml. of methylene chloride and stirred at room temperature for about 20 hours. The reaction mixture is filtered and the methylene chloride removed using a rotary evaporator. The residue is treated with benzene and filtered to remove a small quantity of insoluble material. The benzene is evaporated and the dark, viscous residue is chromatographed using 100 g. of 60 - 100 mesh Florosil activated magnesium silicate and methanol/chloroform graded solvent mixtures. Chromatography yields an oil which is dissolved in ether and treated with a solution of ethereal HCl. The desired compound appears as crystals which are filtered and washed with additional ether to obtain the desired product.
