Development of Kinase Inhibitors via Metal-Catalyzed C⁻H Arylation of 8-Alkyl-thiazolo[5,4-f]-quinazolin-9-ones Designed by Fragment-Growing Studies.

Efficient metal catalyzed C⁻H arylation of 8-alkyl-thiazolo[5,4-f]-quinazolin-9-ones was explored for SAR studies. Application of this powerful chemical tool at the last stage of the synthesis of kinase inhibitors allowed the synthesis of arrays of molecules inspired by fragment-growing studies generated by molecular modeling calculations. Among the potentially active compounds designed through this strategy, FC162 (4c) exhibits nanomolar IC50 values against some kinases, and is the best candidate for the development as a DYRK kinase inhibitor.

Pd-Catalyzed and Copper Assisted Regioselective Sequential C2 and C7 Arylation of Thiazolo[5,4-f]quinazolin-9(8H)-one with Aryl Halides.

A selective functionalization of thiazolo[5,4-f]quinazolin-9(8H)-one has been developed through sequential activation of C-H bonds to furnish diarylated compounds. This strategy allows the regioselective C2 and C7 arylation by a judicious choice of coupling partners and bases, requiring no additional ligands or directing groups. Differently substituted N(8)-benzylated-2,7-diaryl-thiazoloquinazolin-9(8H)-ones were thereby obtained in a facile manner. A one-pot procedure was also performed. These protocols provide a synthetically useful route for late-stage functionalization of this highly valuable scaffold, required in drug discovery.

Ligand-free Pd-catalyzed and copper-assisted C-H arylation of quinazolin-4-ones with aryl iodides under microwave heating.

A microwave-assisted method for the palladium-catalyzed direct arylation of quinazolin-4-one has been developed under copper-assistance. This method is applicable to a wide range of aryl iodides and substituted (2H)-quinazolin-4-ones. This protocol provides a simple and efficient way to synthesize biologically relevant 2-arylquinazolin-4-one backbones.