Table 3.

Potency of Triazoloquinazoline Derivatives in a Functional Assay at Human A_2B Receptors Stably Expressed in CHO Cells

compd	R1 or R3	% inhibitiona,c	IC50 (μM)b,d	pA2d
1a	H	100 (100–100)	1.20 ± 0.43	8.0 ± 0.3
1b	COCH2-Ph	71 (73–69)
3	CH2-Ph	21 (20–22)
5	COCH2(4-NH2-3-I-Ph)	23 (18–27)
6	COCH2(4-NH2-Ph)	90 (85–94)	7.4 ± 4.5
9	COCH2-(4-I-Ph)	42 (39–45)
10	COCH2-(3-Cl-Ph)	45 (55–34)
15	COCH2CH2-Ph	43 (50–36)
16	COCH=CH-Ph	38 ± 14
20	CO(CH2)3-NH-Boc	47 (57–36)
26	CO(CH2)2-NH2	83 (85–80)	13.3 ± 4.0
27	CO(CH2)3-NH2	100 (100–100)	0.27 ± 0.04	8.0 ± 0.3
28	CO(CH2)4-NH2	100 (100–100)	1.77 ± 1.25
29	CO(CH2)5-NH2	79 (73–85)
30	CO(CH2)6-NH2	75 (74–75)
34	CO(CH2)3-COOH		1.90 ± 0.13
35	COCH3	92 (94–90)	2.65 ± 1.00
36	COCH2CH3	66 (75–56)
37	CO(CH2)2CH3	66 (73–58)
38	CO(CH2)3CH3	79 (86–72)
39	COC(CH3)3	89 (92–85)	2.40 ± 1.70
40	CO-OC(CH3)3	92 (94–90)	2.41 ± 1.02
41	CO-Ph	58 (69–47)
42	CO-(3-I-Ph)	38 (51–25)
43	H, R2 = Br	16 (24–9)
44	CO-Ph, R2 = Br	0 (0–0)
45	H	0 (0–0)
46	(CH2)2CH3	0 (0–0)

^aPercentage inhibition by 50 μM of each antagonist of cyclic AMP production induced by 50 μM NECA.

^bConcentration of antagonist inhibiting 50% of cyclic AMP production induced by 50 μM NECA.

^cValues are the means of duplicate measurements (values of individual measurements between parentheses) or are the means of at least three experiments ± SEM.

^dValues are given ± SEM and are the means of at least three experiments.