Trimethylsilylacetylene → 5-Bromo-3-((trimethylsilyl)ethynyl)pyrazin-2-amine

HRID 85024Notes

Reaction equation

Br[C:2]1[C:3]([NH2:9])=[N:4][CH:5]=[C:6]([Br:8])[N:7]=1.C(N(C(C)C)CC)(C)C.[CH3:19][Si:20]([C:23]#[CH:24])([CH3:22])[CH3:21]>CN(C=O)C.[Cu]I.[Pd].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>[Br:8][C:6]1[N:7]=[C:2]([C:24]#[C:23][Si:20]([CH3:22])([CH3:21])[CH3:19])[C:3]([NH2:9])=[N:4][CH:5]=1

Participants

Conditions

Temperature: 120 °C

Procedure

To a solution of 3,5-dibromopyrazin-2-amine (10 g, 40 mmol), copper(I) iodide (0.91 g, 4.7 mmol), diisopropylethylamine (53 mL, 0.55 mol), and tetrakis(triphenylphosphine)-palladium(0) (2.3 g, 1.9 mmol) in DMF (120 mL) that was de-gassed with Ar was added trimethylsilylacetylene (6.7 mL, 48 mmol). The resulting mixture was stirred under an Ar atmosphere for 1 h at 120° C., after which it was evaporated to dryness in vacuo. The residue was subjected to silica gel chromatography eluting with 35% EtOAc in hexanes to give a brown oil that was triturated with hexanes to give the title compound (5.0 g, 47%). 1H NMR (CDCl3, 300 MHz): δ 8.04 (s, 1H), 5.10 (s, 2H), 0.28 (s, 9H). HPLC retention time: 2.75 minutes. MS ESI (m/z): 270.0, 272.0 (M+H)+, calc. 269.

Workup

customafter which it was evaporated to dryness in vacuo
washeluting with 35% EtOAc in hexanes
customto give a brown oil that
customwas triturated with hexanes

Sources & evidence

ORD record: ord-872a4cba408146feb3a51623f6485e94
Source dataset: uspto-grants-2014_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08846909B2

Reaction notes

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