From Type I to Type II: Design, Synthesis, and Characterization of Potent Pyrazin-2-ones as DFG-Out Inhibitors of PDGFRβ

Targeting EphA2: a promising strategy to overcome chemoresistance and drug resistance in cancer

Erythropoietin-producing hepatocellular A2 (EphA2) is a vital member of the Eph tyrosine kinase receptor family and has been associated with developmental processes. However, it is often overexpressed in tumors and correlates with cancer progression and worse prognosis due to the activation of its noncanonical signaling pathway. Throughout cancer treatment, the emergence of drug-resistant tumor cells is relatively common. Since the early 2000s, researchers have focused on understanding the role of EphA2 in promoting drug resistance in different types of cancer, as well as finding efficient and secure EphA2 inhibitors. In this review, the current knowledge regarding induced resistance by EphA2 in cancer treatment is summarized, and the types of cancer that lead to the most cancer-related deaths are highlighted. Some EphA2 inhibitors were also investigated. Regardless of whether the cancer treatment has reached a drug-resistance stage in EphA2-overexpressing tumors, once EphA2 is involved in cancer progression and aggressiveness, targeting EphA2 is a promising therapeutic strategy, especially in combination with other target-drugs for synergistic effect. For that reason, monoclonal antibodies against EphA2 and inhibitors of this receptor should be investigated for efficacy and drug toxicity.

Nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole derivatives: Synthesis of pyrrolopyrazinone, pyrrolotriazinone, and pyrrolooxazinone moieties

Intramolecular nucleophilic and electrophilic cyclization of N-alkyne-substituted pyrrole esters is described. Efficient routes towards the synthesis of pyrrolopyrazinone, pyrrolotriazinone and pyrrolooxazinone have been developed. First, N-alkyne-substituted pyrrole ester derivatives were synthesized. Introduction of various substituents into the alkyne functionality was accomplished by a copper-catalyzed cross-coupling reaction. Nucleophilic cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with hydrazine afforded the 6-exo-dig/6-endo-dig cyclization products depending on the electronic nature of the substituents attached to the alkyne. On the other hand, cyclization of N-alkyne-substituted methyl 1H-pyrrole-2-carboxylates with iodine only resulted in the formation of the 6-endo-dig cyclization product regardless of the substitution of the alkyne functionality.