The esterification of 4,4-bis(4-hydroxyphenyl)pentanoic acid (I) with diazomethane in ethyl ether/methanol gives the methyl ester (II), which is treated with phenylmagnesium bromide in THF to yield 4,4-bis(4-hydroxyphenyl)-1,1-diphenyl-1-pentanol (III). The reduction of (III) with H2 over Pd/C in methanol affords 4,4-bis(4-hydroxyphenyl)-1,1-diphenylpentane (IV), which is finally condensed with azepane (V) and formaldehyde in hot ethanol/water.