Design, synthesis and biological evaluation of novel condensed pyrrolo[1,2-c]pyrimidines featuring morpholine moiety as PI3Kα inhibitors.

Four series of condensed pyrrolo[1,2-c]pyrimidines 6a-d, 8a-d, 10a,b and 12a-e designed as PI3Kα inhibitors were synthesized and evaluated for inhibitory activity and selectivity toward different PI3K isoforms. The tested compounds displayed PI3Kα kinase inhibitory activity at either low micromolar or nanomolar level. In particular, the morpholino-pyrimidopyrrolopyrimidinones 8a-d and morpholino-pyridopyrrolopyrimidine-2-carbonitriles 12a-e proved to be highly potent and selective PI3Kα inhibitors (IC50 = 0.1-7.7 nM). Moreover, the target compounds exhibited considerable cytotoxic activity against cervical cancer cell line HeLa that over-expresses p110α (0.21-1.99 μM). Molecular modeling simulation revealed that, the designed compounds docked well into p110α active site and their complexes are stabilized by a key H-bonding with the backbone amide of Val851 as well as other favorable hydrophobic and H-bond interactions with different amino acids within the enzyme active site.