General procedure for the synthesis of valerylhydrazine from ethyl valerate: hydrazine hydrate (783 μL) was added to a solution of ethanol (20 mL) containing ethyl valerate (420 mg, 3.22 mmol). The resulting solution was heated to reflux for 12 hours. Upon completion of the reaction, the mixture was kept warm and the volatiles were removed under vacuum. The resulting valerylhydrazine was used for subsequent reactions without further purification. Yield: 99%. 1H NMR (400 MHz, CDCl3) δ: 7.25 (s, 1H), 2.15-2.11 (d, J = 7.6 Hz, 2H), 1.64-1.57 (m, 2H), 1.37-1.28 (m, 2H), 0.92-0.88 (t, J = 7.2 Hz, 3H) ppm.
