[CH3:1][C:2]1[N:6]2[CH:7]=[C:8]([N+:12]([O-])=O)[CH:9]=[C:10]([CH3:11])[C:5]2=[N:4][N:3]=1.[H][H]>CO.[Pd]>[CH3:1][C:2]1[N:6]2[CH:7]=[C:8]([NH2:12])[CH:9]=[C:10]([CH3:11])[C:5]2=[N:4][N:3]=1A suspension of 3,8-dimethyl-6-nitro-[1,2,4]triazolo[4,3-a]pyridine (Step 67.3) (14.1 g, 71.9 mmol) and 10% Pd/C (2.75 g, 25.9 mmol) in MeOH (300 mL) was shaken for 5 h under 4 bar hydrogen atmosphere at RT. Further 10% Pd/C was added and the reaction mixture was shaken another 1 hh under hydrogen atmosphere. The mixture was filtered through Celite. The pad of Celite was washed with MeOH and the resulting filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (hexane/(CH2Cl2-MeOH 19:1) 50-100% (CH2Cl2-MeOH 19:1)) to afford the title product as yellow solid. tR: 0.29 min (LC-MS 2); ESI-MS: 163 [M+H]+ (LC-MS 2); TLC (CH2Cl2-MeOH 9:1) Rf=0.26; 1H NMR (400 MHz, DMSO-d6) δ ppm 2.43 (s, 3H) 2.54 (s, 3H) 5.05 (br. s, 2H) 6.75 (br. s, 1H) 7.18 (br. s, 1H).
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