Synthesis and biological evaluation of N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidin-4-amines and their N-arylbenzo[b]thieno[3,2-d]pyrimidin-4-amine analogues as dual inhibitors of CLK1 and DYRK1A kinases

Novel N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidin-4-amines (1) and their N-arylbenzo[b]thieno[3,2-d]pyrimidin-4-amine analogues (2) were designed and prepared for the first time via microwave-accelerated multi-step synthesis. Various anilines were condensed with N′-(2-cyanaryl)-N,N-dimethylformimidamide intermediates obtained by reaction of 3-amino-6-methoxybenzofuran-2-carbonitrile (3) and 3-amino-6-methoxybenzothiophene-2-carbonitrile (4) precursors with dimethylformamide dimethylacetal. The inhibitory potency of the final products against five protein kinases (CDK5/p25, CK1δ/ε, GSK3α/β, DYRK1A and CLK1) was estimated. Compounds (2a–z) turned out to be particularly promising for the development of new pharmacological dual inhibitors of CLK1 and DYRK1A kinases.

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► Synthesis of 26 novel tricyclic N-aryl-7-methoxybenzo[b]furo[3,2-d]pyrimidines.
► Synthesis of 26 novel tricyclic N-aryl-7-methoxybenzo[b]thieno[3,2-d]pyrimidines.
► The inhibitory potency of the final products against five kinases was evaluated.
► Two thieno derivatives are promising as dual inhibitors of DYRK1A and CLK1 kinases.