Cl.NO.C([N:6](C(C)C)C(C)C)C.C(OC([NH:18][C:19]([NH:21][C:22]1[CH:27]=[C:26]([Br:28])[CH:25]=[CH:24][N:23]=1)=S)=O)C>C(O)C>[Br:28][C:26]1[CH:25]=[CH:24][N:23]2[N:6]=[C:19]([NH2:18])[N:21]=[C:22]2[CH:27]=1A mixture of hydroxylamine hydrochloride (20.7 g, 298 mmol) and N-ethyldiisopropylamine (23.1 g, 31.2 ml, 179 mmol) in ethanol (380 ml) is stirred for a few minutes at 25° C. The mixture is then added to 1-ethoxycarbonyl-3-(4-bromo-pyridin-2-yl)-thiourea (18.13 g, 59.6 mmol) and the resulting mixture is refluxed for 1 day. The solvent is evaporated to dryness and the residue triturated for 10 minutes with water (100 ml). The solid is collected by filtration, washed with water and dried affording 7-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine (10 g, 78.8%) as a light yellow solid. mp.: 190-2° C. MS: m/z=212.9, 215.0 (M+H+).
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