Synthesis
Step 4: 2-chloro-4-nitrobenzonitrile (5 g, 0.027 mol) was mixed with hydrazine monohydrate (110 ml) and heated to reaction initiation. Subsequently, the remaining 2-chloro-4-nitrobenzonitrile (35 g, 0.192 mol) was added in batches. The reaction mixture was refluxed for about 30 min after the nitrogen release stopped completely. Upon completion of the reaction, the mixture was slowly poured into stirred ice water. The precipitate was collected by filtration and purified by recrystallization in water to give 2-chloro-4-aminobenzonitrile (25 g, 78% yield, melting point 117 °C).
