The interaction between compounds containing amino and carbamoyl (or thiocarbamoyl) groups in the neighboring positions, on the one hand, and the P2S5-pyridine system, on the other hand, may readily close the 1, 3, 2Miazaphosphorin cycle [1-4]. This approach was used for the synthesis of phosphorus-containing analogs of purines [3] and pyrimidines [4]. The group of pyrazolo-[3, 4-d] pyrimidine derivatives was reported to include compounds ...
