Table 1.

Relative Binding Affinities^a of Compounds of the Salaldox A (1a–d) and Salaldox B (2a–g) series for the Estrogen Receptors α and β

Entry	Ligand	hERα (%)	hERβ (%)	β/α ratio
1	estradiol	(100)	(100)	1
Salaldox A Series
2	1ab	0.007 ± 0.001	0.55 ± 0.11	79
3	1bc	0.92 ± 0.04	0.35 ± 0.01	0.38
4	1cb	0.065 ± 0.016	4.21 ± 0.66	65
5	1dd	0.11 ± 0.03	7.01 ± 1.00	62
Salaldox B Series
6	2ad	0.064 ± 0.016	2.64 ± 0.62	41
7	2b	88.4 ± 18.1	101 ± 2	1.1
8	2c	4.46 ± 0.60	130 ± 25	29
9	2d	1.88 ± 0.30	87.1 ± 15.0	46
10	2e	0.074 ± 0.006	0.64 ± 0.09	8.6
11	2f	1.47 ± 0.04	15.8 ± 3.5	11
12	2g	0.39 ± 0.04	7.90 ± 0.40	20

^aDetermined by a competitive radiometric binding assay with [³H]estradiol; preparations of purified, full-length human ERα and ERβ (Invitrogen, PanVera) were used; see Experimental Section. Values are reported as the mean ± the range or SD of 2 or more independent experiments; the K_d for 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. 13.

^cSee Ref. 16b.

^dSee Ref. 14.