Unforeseen alkylating effect of triethylorthoformate in the synthesis of pyrazolotriazolopyrimidine derivatives

Article abstract of DOI:10.1016/0223-5234(96)88242-0

The final ring closure reaction of 2-phenylamino-3-aminopyrazolo[3,4-d]pyrimidin-4-ones with triethylorthoformate in the synthesis of 1H-pyrazolo[3,4-d][1,2,4]-8H-triazolo[2,3-a]-4H-pyrimidin-4-one derivatives, unexpectedly gave both the desired product a