Tributylvinyltin → 6-Ethenylpyrido[2,3-b]pyrazine

HRID 1175730Notes

Reaction equation

Cl[C:2]1[CH:3]=[CH:4][C:5]2[C:6]([N:11]=1)=[N:7][CH:8]=[CH:9][N:10]=2.[CH:12]([Sn](CCCC)(CCCC)CCCC)=[CH2:13]>C1COCC1.[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>[CH:12]([C:2]1[CH:3]=[CH:4][C:5]2[C:6]([N:11]=1)=[N:7][CH:8]=[CH:9][N:10]=2)=[CH2:13]

Participants

Conditions

Temperature: 65 °C

Procedure

6-chloropyrido[2,3-b]pyrazine (Intermediate 4.2) (3 g, 18.12 mmol, 1.00 eq.) was dissolved in THF (150 mL) and degassed with nitrogen at rt for 10 minutes. Tetrakis (triphenylphosphine) palladium(0) (1.46 g, 1.27 mmol, 0.07 eq.) and vinyltributylstannane (7.47 mL, 23.5 mmol, 1.3 eq.) were added and reaction mixture was stirred at 65° C. for 3 hours. THF was evaporated and crude purified directly by flash chromatography using cyclohexane/ethyl acetate (8/2) to give 2.3 g of the expected compound (Intermediate 4.3) as an orange oil. Amount: 2.3 g; Yield: 81%; Formula: C9H7N3; HPLC Purity: 98%; HPLC H2O TFA 0.1%-ACN TFA 0.05%): Rt (min); Area %=1.32 min; 98%; 1H NMR (DMSO-d6) δ 9.10 (s, 1H), 8.98 (s, 1H), 8.46 (d, 1H, J=8 Hz), 7.95 (d, 1H, J=8 Hz), 6.90 (dd, 1H, Jtrans=17 Hz, Jcis=10 Hz), 6.50 (dd, 1H, Jtrans=17 Hz, Jgem=1.5 Hz), 5.80 (dd, 1H, Jcis=10 Hz, Jgem=1.5 Hz). LC-MS: M/Z ESI: Rt (min) 0.78 min, 158.13 (M+1).

Workup

customdegassed with nitrogen at rt for 10 minutes
customreaction mixture
customTHF was evaporated
customcrude purified directly by flash chromatography

Sources & evidence

ORD record: ord-403f50eeb9d9475f9e8ceb10894fc18f
Source dataset: uspto-grants-2010_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07842698B2

Reaction notes

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