反应详情

Solid magnesium (0.7 g, 30 mmol) was stirred in 15 ml of dry diethyl ether under a nitrogen atmosphere. An iodine crystal and 1 drop of 1-bromopropane was added and the mixture was heated to reflux. The heating source was removed and the remaining 1-bromopropane (2.46 g, 20 mmol) was added in portions. The Grignard reagent was stirred for 1/2 hour at room temperature. 3-Benzyloxy-2-bromopyridine (3.66 g, 13.8 mmol) and a catalytic amount of [1,2-bis(diphenylphosphino)ethane]dichloronickel(II) was dissolved in 200 ml of dry diethyl ether under a nitrogen atmosphere, and the Grignard reagent was added dropwise. The reaction mixture was stirred for 3 hours, and carefully poured into 200 ml of water. The aqueous layer was extracted with 2×100 ml of diethyl ether. The combined organic layers were dried overmagnesium sulfate and the solvent was evaporated. The crude product was purified by column chromatography over silica gel 60, using 50% of diethyl ether in petroleum ether as the eluent to afford 2.25 g (71%) of 3-benzyloxy-2-propylpyridine. 1H--NMR (CDCl3, 200 MHz) δ: 0.98 (t,3 H); 1.77 (sextet, 2 H); 1.86 (t, 2 H); 5.07 (s, 2 H); 7.02-7.16 (m, 2 H); 7.27-7.45 (m, 5 H); 8.12 (dd, 1 H).

1. temperaturethe mixture was heated to reflux
2. customThe heating source was removed
3. extractionThe aqueous layer was extracted with 2×100 ml of diethyl ether
4. dry with materialThe combined organic layers were dried overmagnesium sulfate
5. customthe solvent was evaporated
6. customThe crude product was purified by column chromatography over silica gel 60