Disclosed are 2-substituted adenosine derivatives of the formula ##STR1## in which R represents a substituted amino grouping of the formula ##STR2## as defined herein; pharmaceutically acceptable ester derivatives thereof in which free hydroxy groups are esterified in the form of a pharmaceutically acceptable prodrug ester; and pharmaceutically acceptable salts thereof; pharmaceutical compositions comprising said compounds; methods for their preparation; and their use in mammals as therapeutically effective adenosine-2 (A-2) agonists.