N-6-Cycloalkyl-2-substituted adenosine derivatives as selective, high affinity adenosine A(1) receptor agonists

A series of new selective, high affinity A(1)-AdoR agonists is reported. Compound 23 that incorporated a carboxylic acid functionality in the 4-position of the pyrazole ring displayed K-iL value of 1 nM for the A(1)-AdoR and > 5000-fold selectivity over the A(3) and A(2A)-AdoRs. In addition, compound 19 that incorporated a carboxamide functionality in the 4-position of the pyrazole ring displayed subnanomolar affinity for the A(1)-AdoR (K-iL = 0.6 nM) and > 600-fold selectivity over the A(3) and A(2A)-AdoRs. (c) 2006 Elsevier Ltd. All rights reserved.