反应详情

To a stirred solution of 20 mL (210 mmol) of 2-bromopyridine in 500 mL of dry ether at −78° C. under Ar was added 85 mL of a 2.5 M solution of n-butyllithium in hexane in a slow stream. After stirring in the cold for 30 min, the solution was transferred over a 5 min period via two cannula into a 0° C. stirred solution of 100 mL (736 mmol) of diethyl oxalate in 1.0 L of dry ether under Ar. After stirring for 2 h in the cold, the reaction mixture was washed with 600 mL of sat. NaHCO3, water, and brine. The solution was dried over MgSO4 and the solvents concentrated at reduced pressure to give a red oil that was purified by SiO2 chromatography (10×15 cm) using 1:4 to 35:65 EtOAc-hexanes. The product-containing fractions were concentrated at reduced pressure to afford I-1-1 as a reddish oil: 1H NMR (CDCl3) δ1.42 (t, 3H), 4.45-4.55 (m, 2H), 7.55-7.6 (m, 1H), 7.9-7.95 (m, 1H), 8.11 (d, 1H), 8.78 (d, 1H).

1. waitthe solution was transferred over a 5 min period via two cannula into a 0° C.
2. stirringAfter stirring for 2 h in the cold, the reaction mixture
3. washwas washed with 600 mL of sat. NaHCO3, water, and brine
4. dry with materialThe solution was dried over MgSO4
5. concentrationthe solvents concentrated at reduced pressure
6. customto give a red oil that
7. customwas purified by SiO2 chromatography (10×15 cm)
8. concentrationThe product-containing fractions were concentrated at reduced pressure
9. customto afford I-1-1 as a reddish oil