反应详情

A mixture of intermediate 3 (10 g) and potassium hydroxide (14 g) in 2-propanol (200 ml) was stirred and refluxed for 6 hours. The reaction mixture was cooled and the solvent evaporated. Water was added to the residue and evaporated again. The residue was stirred in water and the resulting precipitate was filtered off, washed with water and purified by column chromatography on silica gel (eluent: CH2Cl2 /(CH3 OH/NH3) 90/10). The pure fractions were collected and the solvent evaporated, yielding 5.14 g (64%) of 5-chloro-2,3-dihydro-7-[3-(4-piperidinyl)-1,2,4-oxadiazol-5-yl]-4-benzofuranamine (intermediate 4; mp. 219.0° C.).

1. temperaturerefluxed for 6 hours
2. temperatureThe reaction mixture was cooled
3. customthe solvent evaporated
4. additionWater was added to the residue
5. customevaporated again
6. stirringThe residue was stirred in water
7. filtrationthe resulting precipitate was filtered off
8. washwashed with water
9. custompurified by column chromatography on silica gel (eluent: CH2Cl2 /(CH3 OH/NH3) 90/10)
10. customThe pure fractions were collected
11. customthe solvent evaporated