Adenosine A1 receptor antagonist, FK838, has been synthesized in 44% overall yield by a five-step sequence which is operationally straightforward and readily carried out on a large scale. Investigations into the 1, 3-dipolar cycloaddition process that afforded a pyrazolo [1, 5- a] pyridine derivative are also described. Process improvements and optimization of each step permitted elimination of column chromatography, resulting in a practical and cost- ...