Table 1.

Structure-activity relationships on the aniline ring.

Cmpd	R	X	EC50 (μM)a	% VUAA1 efficacyb
6a (VUAA1)	4-ethyl	H	35.1	100 %
6b	3-ethyl	H	-	No agonism
6c	4-methyl	H	-	No agonism
6d	4-propyl	H	94.1	57 %
6e	4-butyl	H	-	No agonism
6f	4-isopropyl	H	11.7	127 %
6g	4-tertbutyl	H	LA d	42 % d
6h	4-acetyl	H	84.7	96 %
6i	4-methoxy	H	-	No agonism
6j	4-bromo	H	-	No agonism
6k	4-vinyl	H	102	57 %
6l	4-ethynyl	H	-	No agonism
6m	2-methyl-4-ethyl	H	-	No agonism
6n	2-bromo-4-ethyl	H	-	No agonism
6o	cyclohexylc	-	-	No agonism
6p	4-ethyl	N	-	No agonism

^aMean result of 4 experiments.

^bMaximum agonism of the compound, normalized to the activity of VUAA1.

^cEntire ring replaced.

^dLA = Low agonism. Compound shows agonism only at the highest concentration tested, but no EC₅₀ could be calculated. Maximum observed agonism, but from an incomplete curve.