BACKGROUND OF THE INVENTION
Adenosine is an autocoid produced in many tissues to mediate various functions through four receptor subtypes, A1, A2A, A2B and A3. All four receptors belong to the class of G-protein coupled receptors (GPCRs), which contain seven helical hydrophobic domains that span
FIELD OF THE INVENTION
This invention relates to at least one compound of the formula I
##STR00002## or pharmaceutically acceptable salts thereof, wherein X, R and R.sub.1 are described in this application. These compounds are believed to act primarily as Adenosine 2B Receptor Antagonists and