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. Author manuscript; available in PMC: 2015 Jun 19.
Published in final edited form as: J Med Chem. 1994 Mar 4;37(5):636–646. doi: 10.1021/jm00031a014

Table 1.

Affinities of 5′-Uronamide Derivatives in Radioligand Binding Assays at Rat Brain A1, A2, and A3 Receptorsa-c

graphic file with name nihms-698956-t0005.jpg
Ki (nM) or % inhibition
compd R1 R2 Ki(A1)a Ki(A2)b Ki(A3)c A1/A3 A2/A3
1 d H NH2 72.6 120 1410 ± 60 0.051 0.085
2 d Me NH2 83.6 66.8 72 ± 16 1.2 0.93
3 d Et NH2 6.3 10.3 113 0.071 0.091
4 d cyclopropyl NH2 6.4 13.4 1600 ± 70 0.0040 0.0084
5 H2NEt NH2 0% (10−5) 12.5% (10−5) 14700 ± 2540 >1 >1
6 t-BocNHEt NH2 0% (10−5) 0% (10−5) 18000 ± 4270 >1 >1
7 Me OH 0% (10−4) 6.2 ± 4.2% (10−4) 6220 ± 1220f >10 >10
8 e Et OH 44% (10−4) 31% (10−4) 5000 >1 >1
a

Displacement of specific [3H]PIA binding, unless noted, in rat brain membranes expressed as Ki ± SEM in nM (n = 3).

b

Displacement of specific [3H]CGS 21680 binding, unless noted, in rat striatal membranes, expressed as Ki ± SEM in nM (n = 3).

c

Displacement of specific binding of [125I] APNEA10 or [125I]-N6-(4-amino-3-iodobenzyl)adenosine-5′-N-methyluronamide28 from membranes of CHO cells stably transfected with the rat A3-CDNA, expressed as Ki ± SEM in nM (n = 3–5).

d

Values at A1 and A2 receptors are taken from Bruns et al.29 Ki values at A1 receptors are vs specific binding of [3H]-N6-cyclohexyladenosine. Ki values at A2 receptors are vs specific binding of [3H]NECA in the presence of 50 nM CPA in rat striatal membranes.

e

Values from ref 8.

f

Vs[125I]-N6-(4-amino-3-iodobenzyl)adenosine-5′-N-methyluronamide.