Table 1.

Inhibition of UT-A1 and UT-B urea transport by 2,7-disubstituted fluorenoneanalogs.

Structure	Functional group	UT- A1 IC50 (μM)	UT-B IC50 (μM)
	1	>50	>50
	R
	2 H	>50	>50
	3 COCH3	1	1.5
	4 COCH2CH3	15	5
	5 COCH(CH3) 2	18	50
	6 CO(CH2) 2CH3	>50	>50
	7 COCF3	10	7.5
	8 CONH2	2	1.2
	9 SO2CH3	1.5	2.5
	10 SO2(CH2)3	>50	>50
	11 COCH2Br	30	10
	12 COCH2OH	20	25
	13 COCH2O(CH2)2OMe	>50	50
	14 COCH2N3	20	30
	15 COCH2OBn	>50	>50
	16 CO(CH) 2CO2H	30	>50
	X
	17 CNHOH	12	25
	18 CHOH	>50	20
	20 SO2	15	2
	R
	21 H	>50	>50
	22 COCH3	18	20
	23 COCH2OBn	>50	>50
	24 SO2CH3	>50	30