Preparation of 4,6‐diaminopyrazolo[3,4‐<i>d</i>] pyrimidines with variations in substitution at the 1‐ and 3‐positions

Abstract

Abstract A number of new derivatives of 4,6‐diaminopyrazolo[3,4‐ d ]pyrimidines substituted in the 1‐ and/or 3‐positions have been obtained from reactions of guanidine carbonate with 1‐ and/or 3‐substituted‐5‐amino‐4‐cyanopyrazoles. Use of triethanolamine as a reaction medium permitted preparation of certain derivatives which could not be obtained from the previously described fusion procedure. Some derivatives of 4‐aminopyrazolo[3,4‐ d ]pyrimidine with substitution at the 1 ‐ and/or 3‐positions were also obtained from reactions of formamide with the same 5‐amino‐4‐cyanopyrazoles. The new compounds were screened for in vivo antimalarial activity, but were found inactive.