反应详情

A mixture of 2-chloro-3-pyridin-3-yl-propionaldehyde (crude from above) and thiourea (14.8 g, 0.194 mol) in ethanol (200 mL) was heated to reflux overnight. The solvent was removed and the residue was diluted with dichoromethane (1.2 L) and then washed with sodium hydroxide (10% aqueous solution, 400 mL) and water (200 mL). The organic layer was extracted three times with hydrochloric acid (5% aqueous solution, 400 mL) and the combined aqueous layer was brought to between pH 9 and 10 with sodium hydroxide (10% aqueous solution). The resulting precipitate was filtered to give the crude product, which was recrystallized, from ethyl acetate and hexanes to give the pure product (5.1 g, 0.023 mol, 5.6% from 2-methoxy-pyridin-3-ylamine). ESI-MS m/z calc. 221.1. found 222.2 (M+1)+.

1. temperaturewas heated
2. temperatureto reflux overnight
3. customThe solvent was removed
4. additionthe residue was diluted with dichoromethane (1.2 L)
5. washwashed with sodium hydroxide (10% aqueous solution, 400 mL) and water (200 mL)
6. extractionThe organic layer was extracted three times with hydrochloric acid (5% aqueous solution, 400 mL)
7. filtrationThe resulting precipitate was filtered
8. customto give the crude product, which
9. customwas recrystallized, from ethyl acetate and hexanes