CSC1N=NC(C(NC(=O)OC(C)(C)C)C)=CN=1.[CH3:19][O:20][C:21]1[CH:22]=[C:23]([NH:31][C:32]2[N:33]=[N:34][C:35]([CH:38]([NH:40]C(=O)OC(C)(C)C)[CH3:39])=[CH:36][N:37]=2)[CH:24]=[C:25]([O:29][CH3:30])[C:26]=1[O:27][CH3:28].[ClH:48]>CO.O1CCOCC1>[ClH:48].[NH2:40][CH:38]([C:35]1[N:34]=[N:33][C:32]([NH:31][C:23]2[CH:22]=[C:21]([O:20][CH3:19])[C:26]([O:27][CH3:28])=[C:25]([O:29][CH3:30])[CH:24]=2)=[N:37][CH:36]=1)[CH3:39]To a stirred solution of tert-butyl 1-[3-(methylthio)-1,2,4-triazin-6-yl]ethylcarbamate (Intermediate 8) (1.2 g, 3.1 mmol) in methanol (10 mL) was added 4N HCl in dioxane (10 mL). After stirring for 30 minutes the volatiles were removed under reduced pressure to provide 6-(1-aminoethyl)-N-(3,4,5-trimethoxyphenyl)-1,2,4-triazin-3-amine hydrochloride as a foam. The foam was dissolved in methanol, ammonium hydroxide was added to neutralize the acid, and silica gel (5 g) was added followed by evaporation of the volatiles under reduced pressure. The pre-adsorbed solids were loaded into a solid loading cartridge and subjected to an isocratic elution using dichloromethane: methanol: ammonium hydroxide (95:4:1) using a RediSep silica gel cartridge (40 g; ISCO). The appropriate fractions were combined and concentrated under reduced pressure to give 6-(1-aminoethyl)-N-(3,4,5-trimethoxyphenyl)-1,2,4-triazin-3-amine (680 mg) as a yellow solid. 1H NMR (CDCl3): δ8.42 (s, 1H), 7.38 (s, 1H), 6.97 (s, 2H), 4.38 (d, J=7.0 Hz, 1H), 3.90 (s, 6H), 3.84 (s, 3H), 1.62 (br, 2H), 1.52 (d, J=7.0 Hz, 3H), 1.43 (s, 9H). MS m/z 306 (M+1).
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