Versions of adenosine receptor agonist GR79236 (1), labelled either with ca
rbon-14 (9) at C-8 of the purine ring or with tritium (15) in the cyclopent
yl ring, were prepared in overall yields of 64% and 25% respectively. A mas
s labelled [M+4] version (24) containing carbon-13, nitrogen-15, and deuter
ium was also prepared in 3% yield.