(a) Synthesis of methyl 2-aminobenzo[d]oxazole-5-carboxylate (3), Reagents and conditions: a Al(NO3)3, Acetic anhydride, gl. AcOH, rt, 1.5 h, 85% b Na dithionite, Acetone, 0.5N NaOH, reflux, 1 h, 70% c CNBr, MeOH, rt, 3–4 h, 70%. (b) Synthesis of ethyl 2-aminothiazole-4-carboxylate (4), Reagents and conditions: EtOH, reflux, 24 h, 72%