Syntheses based on the tautomerism of purine and pyrimidine derivatives.

Synthetic applications of the tautomerism based on purine and pyrimidine derivatives were investigated. Particularly, chloropyrimidine derivatives, which were reactive enough to go back to the more stable lactam form, were used for dehydration and desulfhydration. Alkoxypyrimidines were thermally cleaved to give olefins or esters, together with the lactim to lactam transformation. The extrusion of alkylthio group from thioalkyl purines or pyrimidines took place under bacic conditions to give olefin, indicating another tautomeric transformation.