N-bromobutanimide → 3-bromo-5-(tetrahydro-2H-pyran-4-yl)pyrazin-2-amine

HRID 595787Notes

Reaction equation

[O:1]1[CH2:6][CH2:5][CH:4]([C:7]2[N:8]=[CH:9][C:10]([NH2:13])=[N:11][CH:12]=2)[CH2:3][CH2:2]1.C1C(=O)N([Br:21])C(=O)C1>CC#N.C(OCC)(=O)C>[Br:21][C:9]1[C:10]([NH2:13])=[N:11][CH:12]=[C:7]([CH:4]2[CH2:3][CH2:2][O:1][CH2:6][CH2:5]2)[N:8]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To an ice cold solution of 5-(tetrahydro-2H-pyran-4-yl)pyrazin-2-amine (2.8 g, 15.6 mmol) in CH3CN (52 mL) was added NBS (2.78 g, 15.62 mmol) in two portions at 0° C. The reaction mixture was stirred at 0° C. for 1 h. The reaction mixture was diluted with ethyl acetate and was washed with saturated sodium carbonate solution, water, brine, dried and concentrated. The crude 3-bromo-5-(tetrahydro-2H-pyran-4-yl)pyrazin-2-amine (3.9 g, 97%) was used for the next step without further purification. LCMS (m/z): 258/260 (MH+), 0.52 min; 1H NMR (400 MHz, CDCl3) δ ppm 7.83 (s, 1H), 4.90 (br. s., 2H), 4.14-4.02 (m, 2H), 3.59-3.43 (m, 2H), 2.83 (d, J=5.5 Hz, 1H), 1.91-1.77 (m, 4H).

Workup

washwas washed with saturated sodium carbonate solution, water, brine
customdried
concentrationconcentrated
customThe crude 3-bromo-5-(tetrahydro-2H-pyran-4-yl)pyrazin-2-amine (3.9 g, 97%) was used for the next step without further purification
custom258/260 (MH+), 0.52 min

Sources & evidence

ORD record: ord-5ff3227f2e7a40348cdc81b87a756af6
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09242996B2

Reaction notes

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