High Throughput Synthesis of Extended Pyrazolo[3,4-d]dihydropyrimidines

Thirteen 5-hetarylaminopyrazoles were synthesized in 62-93% yield through the arylation of 1-isopropyl- and 1-phenyl-5-aminopyrazoles with electrophilic hetarylhalides under optimized conditions. Condensation of 5-hetarylaminopyrazoles with carbonyl compounds facilitated by AcOH or Me₃SiCl furnished 23 pyrazolo[3,4-d]dihydropyrimidines in 69-86% yield. The target compounds were isolated through simple crystallization. The scope and limitation of the method are discussed.

Ryabukhin S. V.; Granat D. S.; Plaskon A. S.; Shivanyuk A. N.; Tolmachev A. A.; Volovenko Y. M.
ACS Comb. Sci. 2012, 14 (8), 465-470
DOI: 10.1021/co300063x