Synthesis of 6-(1H-Pyrrol-1-yl)azolo[1,5-a]pyrimidin-7-amines by the Clauson–Kaas Reaction

A series of pyrrolyl-substituted azolo[1,5-a]pyrimidine derivatives have been synthesized for the first time by the Clauson–Kaas reaction of the corresponding azolo[1,5-a]pyrimidine-6,7-diemines with 2,5-dimethoxytetrahydrofuran. The reaction has been found to selectively involve the amino group at the 6-position. The proposed approach makes it possible to obtain 6-(1H-pyrrol-1-yl)azolo[1,5-a]pyrimidin-7-amines in 64–85% yields with high purity. The product structure has been confirmed by NMR spectroscopy and X-ray analysis. The obtained results significantly extend the potential of modification of azolo[1,5-a]pyrimi­dines and open prospects for target-oriented synthesis of their functionalized derivatives.