A concise synthesis of substituted 4-alkylaminopyrazolo[3,4-d]pyrimidines

Abstract

4-Alkylamino-1-methylpyrazolo[3,4-d]pyrimidine-3-carbonitriles have been synthesised in 54–81% yields by condensation of N-substituted amides with 5-amino-1-methylpyrazole-3,4-dicarbonitrile via a Dimroth rearrangement in what is formally an anhydrous medium; the procedure thus permits the synthesis of pyrazolo[3,4-d]-pyrimidines with substituents sensitive to hydration.