Synthesis of pyrido[2,1-b]- and thiazolo[2,3-b]purines

Some pyrido2,1-b]- and thiazolo2,3-b]purines, tricyclic compounds structurally related to 1,2,4]triazolo1,5-c]quinazolines 1 have been synthesized with a view to study their possible adenosine and benzodiazepine receptors affinity.