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

Participants

Reaction Conditions

Reaction Steps

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).

Provenance & Evidence