Abstract: The present invention provides 8-substituted 1,3,7-trialkylxanthines useful as A.sub.2 -selective adenosine receptor antagonists and compositions comprising such compounds. Examples of the 8-substituted 1,3,7-trialkyl xanthines include: ##STR1## In compound (a), R.sub.1, R.sub.3, and R.sub.7 are methyl and X is one to three substituents, which may be the same or different and selected from the group consisting of amino, C.sub.1 -C.sub.4 alkylcarbonylamino, carboxy C.sub.2 -C.sub.4 alkylcarbonylamino, halo, C.sub.1 -C.sub.3 alkyloxy, amino C.sub.1 -C.sub.4 alkyloxy, C.sub.1 -C.sub.4 alkyloxy carbonylamino, amino C.sub.1 -C.sub.4 alkenyloxy, isothiocyanato, and diazonium tetrafluoroborate. In compound (b), R.sub.1, R.sub.3, and R.sub.7 are methyl, R.sub..beta. is hydrogen or methyl, and X is selected from the group consisting of R, C(.dbd.O)OR, and C(.dbd.O)NH--R, wherein R is a C.sub.1 -C.sub.6 alkyl.

Abstract: The present invention provides N.sup.6 -benzyladenosine-5'-N-uronamide and related substituted compounds, particularly those containing substituents on the benzyl and/or uronamide groups, and modified xanthine ribosides, as well as pharmaceutical compositions containing such compounds. The present invention also provides a method of selectively activating an A.sub.3 adenosine receptor in a mammal, which method comprises acutely or chronically administering to a mammal in need of selective activation of its A.sub.3 adenosine receptor a therapeutically effective amount of a compound which binds with the A.sub.3 receptor so as to stimulate an A.sub.3 receptor-dependent response.