2-Amino-3-bromo-5-methylpyrazine

To a solution of 5-methylpyrazin-2-amine (5.00g, 45.8 mmol) and pyridine (4.35g, 55.0 mmol) in DCM (250 mL) was added bromine (8.80 g, 55.0 mmol). The mixture was stirredat rt overnight. To the reaction mixture was added water (150 mL), and the resulting mixture waspartitioned. The organic layer was washed with saturated brine (100 mL), dried over anhydroussodium sulfate and filtered. The filtrate was concentrated in vacuo to give the title compound asa yellow solid (7.64 g, 88 percent).MS (ESI, pos. ion) m/z: 190.2 [M+Ht;1H NMR (400 MHz, CDCh) 8 (ppm): 7.83 (s, lH), 4.93 (s, 2H), 2.41 (s, 3H).[00790] To a mixture of 5-methylpyrazin-2-amine (10 g, 92 mmol) in DCM (300 mL) was added BS (16 g, 91.63 mmol) in one portion at 0 °C under N2. The mixture was stirred at 30 °C for 1 hr. The resulting mixture was poured into saturated aq. Na2S03 (100 mL) and the aqueous phase was extracted with EtOAc. The combined organic layers were washed with brine, dried with Na2S04, filtered and concentrated under reduced pressure. The residue was purified by column chromatography to afford 3-bromo-5-methyl-pyrazin-2-amine (12 g, 69percent yield, ) as a light yellow solid. MR (400 MHz, CDCh-d) δ ppm 7.82 (s, 1H) 4.79 - 5.03 (m, 2 H) 2.39 (s, 3 H).Step 1. To a suspension of 5-methylpyrazin-2-amine (1.09g, 10 mmol) in chloroform (100 mL) was added pyridine(0.85 ml., 10.5 mmol). The mixture was stirred in a foilwrappedflask fitted with an addition funnel, and a solution ofbromine (0.54 ml., 10.5 mmol) in chloroform (10 mL) wasadded dropwise over 10 min. The mixture was allowed toreact an additional 20 minutes after addition was completeand then poured into a separatory funnel containing 10 mLwater. The phases were separated and the organics washedagain with water, dried over sodium sulfate, filtered and concentratedin vacuo. The resulting red oil was purified by silicagel chromatography with 12-100percent EtOAc/hexanes. Themajor UV active peak was collected to give 3-bromo-5-methylpyrazin-2-amine (1.06 g, 5.64 mmol, 56.4percent yield) as a cream-colored solid.A solution of HBr/CHExample 171 Preparation of 3-cyclohexyl-5-methyl[1, 2, 4]triazolo[4, 3-a]pyrazin-8-amine To a reaction container for microwave were added An N-methylpyrrolidone solution (10.0 mL) of [00791] To a mixture of

Molecular Weight:188.03
XLogP3:0.9
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Exact Mass:186.97451
Monoisotopic Mass:186.97451
Topological Polar Surface Area:51.8
Heavy Atom Count:9
Complexity:98.2
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes