Are there alternatives to Axitinib Impurity 1 (CAS: 885126-40-9) in synthesis?

Alternative reagents to Axitinib Impurity 1 (CAS: 885126-40-9) may include similar functional group equivalents or analogs such as various tyrosine kinase inhibitors. Isomers and structural homologues can also be considered. These alternatives can offer different reactivity profiles or synthetic pathways, but their selection should be based on the specific requirements of the synthesis and the analytical tools available for their detection.