Identification of a Novel Series of Potent TrkA Receptor Tyrosine Kinase Inhibitors

Scheme 1

Synthesis of compound 5: (a) Cs₂CO₃, MeCN, rt; (b) DIPEA, DCM, rt; (c) iron, NH₄Cl, MeOH/water, reflux; (d) Ac₂O, rt.