89415-54-3

70232-59-6

89415-54-3

Step 2. Synthesis of 5-bromo-N2-methylpyridine-2,3-diamine: The crude product was dissolved in a solvent mixture of acetic acid (10 mL) and water (2.5 mL) followed by addition of iron powder (445 mg, 7.97 mmol). The reaction mixture was stirred at room temperature for 40 min, after which it was slowly poured into 5N NaOH solution (40 mL). The resulting suspension was briefly cooled in an ice water bath and subsequently filtered through a diatomaceous earth (Celite) pad. The diatomite pads were washed with distilled water, ethyl acetate (EtOAc) and a 10:1 solvent mixture of dichloromethane/methanol (DCM/MeOH). After separating the two-phase solution, the aqueous phase was extracted with a 10:1 solvent mixture of dichloromethane/methanol. The solution was again filtered through a diatomaceous earth (Celite) pad and the pad was washed with methanol. The methanol washings were combined with the organic extract, concentrated, and dried under high vacuum in a water bath at about 60 °C to afford the target compound 5-bromo-N2-methylpyridine-2,3-diamine (427 mg, yield about 100%). The structure of the product was confirmed by liquid chromatography-mass spectrometry (LCMS) analysis (retention time 0.7 min, mass-to-charge ratios m/z 202 and 204, corresponding to the [MH+] peak). After a two-step reaction, the target compounds were obtained in near-quantitative yields. The mass spectrum (ESI positive ion mode) showed m/z: 202 (MH+, 79Br isotope), 204 (MH+, 81Br isotope). The exact masses of C6H8BrN3 were calculated to be 201 (79Br isotope) and 203 (81Br isotope), respectively.