Abstract: A compound, which can act as inhibitors of protein kinases, especially Class III RTKs such as FLT3, PDGFR?, c-KIT and/or CSF-1R kinases, for the treatments of diseases or disorders mediated by such kinases, has a structure of formula (I): or a stereoisomer, a tautomer, a pharmaceutically acceptable salt, a binder of a Proteolysis-Targeting Chimera (PROTAC) thereof. The compound can be used in the treatments of diseases or conditions mediated by FLT3, PDGFR, c-KIT, and/or CSF-1R kinases, or mediated by a mutant kinase of FLT3, PDGFR, c-KIT, and/or CSF-1R kinases. Such diseases or conditions may include cancers, autoimmune diseases, and bone resorptive diseases.

Abstract: A regioselective one-step process for the synthesis of 2-hydroxyquinoxaline of Formula (1) or tautomers thereof: comprising reacting 1,2-phenylenediamine of Formula (2): with an excess amount of glyoxylic acid, glyoxylic acid monohydrate, or a 2,2-dialkoxyacetic acid of Formula (3): at a low temperature; wherein R1 and R2 are as defined in the specification.