Table 1. Relative Binding Affinities^a of Aldoxime 1 and Ketoximes 2a–l for the Estrogen Receptors α and β.

ligand	hERα (%)	hERβ (%)	β/α ratio
estradiol	(100)	(100)	1
1b	0.064 ± 0.016	2.6 ± 0.6	41
2a	0.54 ± 0.03	46 ± 14	85
2b	3.0 ± 0.6	46 ± 9	15
2c	0.16 ± 0.00	12 ± 3	75
2d	1.9 ± 0.5	49 ± 5	26
2e	<0.005	0.011 ± 0.000	>2
2f	<0.005	<0.005
2g	<0.005	0.015 ± 0.003	>3
2h	<0.005	0.099 ± 0.030	>20
2i	0.10 ± 0.02	1.6 ± 0.1	16
2j	<0.005	<0.005
2k	0.033 ± 0.008	1.1 ± 0.1	33
2l	<0.005	<0.005
2m	0.036 ± 0.006	0.76 ± 0.10	21

^aDetermined by a competitive radiometric binding assay with [³H]estradiol. Preparations of purified, full-length human ERα and ERβ (PanVera) were used; see Experimental Section. Values are reported as the mean ± the range or SD of two or more independent experiments. The K_d of estradiol for ERα is 0.2 nM and for ERβ is 0.5 nM. K_i values for the new compounds can be readily calculated by using the formula K_i = (K_d[estradiol]/RBA) × 100.

^bSee ref (13b).