1: 84 percent / 2 N NaOH / methanol / 1 h 2: 1) Et3N, ethyl chloroformate, 2) NH3 / 1) CH2Cl2, 15 to 20 deg C, 1 h 3: 70 percent / pyridine, trifluoroacetic anhydride / dioxane / 16 h / 20 °C 4: NH2OH*HCl, K2CO3 / ethanol; H2O / 1 h / Heating 5: 160 °C View Scheme

n-butyllithium; acetic acid; 1,1,1,3,3,3-hexamethyl-disilazane; trichlorophosphate in tetrahydrofuran; n-heptane; water; toluene

in N-methyl-acetamide; isocyano-acetic acid ethyl ester; water; acetic acid

Yield given. Multistep reaction;