Step 2: Synthesis of 4-(pyridin-3-yl)thiazol-2-amine: 2-bromo-1-(pyridin-3-yl)ethanone (2 g, 1 eq.) was dissolved in ethanol (18.46 mL) followed by addition of thiourea (0.543 g, 0.7 eq.). The reaction mixture was heated to reflux for 2 hours. Upon completion of the reaction, the mixture was cooled to 4 °C. During this process, the product precipitated as dihydrobromide. The precipitate was collected by filtration and dried. The resulting 4-(pyridin-3-yl)thiazol-2-amine dihydrobromide was dissolved in warm water (11 mL) and stirred for 5 minutes. Subsequently, aqueous ammonium hydroxide solution (17 mL) was added to this solution and stirring was continued. At this point, the target product slowly precipitated as a yellow solid. The solid product was separated by filtration and dried under vacuum conditions to give 2 g of 4-(pyridin-3-yl)thiazol-2-amine in 56% yield. The product was analyzed by LCMS showing m/z of 178.01 (M + H); 1H NMR (400 MHz, CD3OD) data were as follows: δ 8.96 (d, J=0.80 Hz, 1H), 8.44 (dd, J=1.60,4.80 Hz, 1H), 8.19-8.22 (m, 1H), 7.43-7.47 (m, 1H), and 7.05 (s, 1H).
