5-(3-Chloro-phenyl)-[1,3,4]thiadiazol-2-ylamine

79-19-6

535-80-8

70057-67-9

5.1.1 Synthesis of 5-(3-chlorophenyl)-1,3,4-thiadiazol-2-amine (67): 3-chlorobenzoic acid (5.18 g, 25 mmol) and N-amino thiourea (2.28 g, 25 mmol) were dissolved in POCl3 (7 ml), and the reaction was stirred vigorously for 0.5 hr at 75 °C. After completion of the reaction, H2O (30 ml) was added and the reaction mixture was heated to reflux for 4 hours. Subsequently, the reaction solution was adjusted with 50% NaOH solution to pH 8. The reaction mixture was filtered and the filter cake was recrystallized with ethanol to give the target product 67 as yellow crystals. Yield: 75%; Melting point: 212-214 °C (EtOH). eSI-MS m/z: 212.1 [M + H]+; 1H NMR (CDCl3) δ 7.49-7.50 (m, 2H), 7.54 (s, 2H), 7.70-7.71 (m, 1H), 7.80 (s, 1H).