The low stereospecificity of the enantiomers of 1-[(benzofuran-2-yl)-4-chlorophenyl-methyl]imidazole (6, R = H, R’ = 4′-Cl) and the corresponding 4-fluoro compound as inhibitors of aromatase (P450Arom) has been explored using 1-(5,7-dichlorobenzofuran-2-yl)-1-(1H-imidaz-1-yl)ethane (7, R1=R2 = Cl, R = CH3), -propane (7, R1=R2 = Cl, R = C2H5), and the corresponding 5,7-dibromo compounds resolved as their dibenzoyl-D (or -L) tartrates.
Low enantioselectivity ratios of 4.8 (5,7-diCl) and 12.6 (5,7-diBr) were shown for the ethanes. The values for the corresponding propanes were 8.3 and 5.2, respectively, and for these compounds the stereoselectivity was reversed.