Design, synthesis and biological activity of acyl substituted 3-amino-5-methyl-1,4,5,7-tetrahydropyrazolo[3,4-b]pyridin-6-ones as potential hypnotic drugs

Among the known non-benzodiazepinic hypnotic drugs acting on the α1 subunit of the GABA-A receptor, Zolpidem (2a), Zaleplon (1b) and Indiplon (1a) have showed high affinity and selectivity. Following a design methodology including pharmacophoric requirements and ADME-predicted properties, we have synthesized a library of 3-amino-4,5-dihydro-1H-pyrazolo[3,4-b]pyridin-6(7H)- ones (3) and their N1-alkyl derivatives (4) as new scaffolds for designing non-benzodiazepine BZ receptor ligands.