反应详情

Cyclopentyl bromide (20g, 134 mmol) is added slowly (over 30 minutes) to a stirred suspension of potassium carbonate (27.6 g, 200 mmol) in N,N'-dimethylimidazolidinone (75 mL) containing 3-hydroxy-4-nitrobenzoic acid (9.15 g, 50 mmol) at 85° C. and then stirring is continued for 14 hours. The mixture is allowed to cool and then filtered. The filtrate is diluted with water (100 mL) then extracted with toluene (2×100 mL). The combined organic extract is dried over magnesium sulfate and then the solvent is removed under reduced pressure to give a brown mobile oil. This oil is subjected by flash chromatography on silica gel (dichloromethane as eluent) and the eluent evaporated under reduced pressure to give cyclopentyl 3-cyclopentyloxy-4-nitrobenzoate (10.2 g, 81.6%) as a yellow solid m.p. 45.5-°46.5° C. [Elemental analysis: C,63.7; H,6.66; N,4.37%; calculated: C,63.93; H,6.63; N, 4.39%].

1. temperatureto cool
2. filtrationfiltered
3. additionThe filtrate is diluted with water (100 mL)
4. extractionthen extracted with toluene (2×100 mL)
5. extractionThe combined organic extract
6. dry with materialis dried over magnesium sulfate
7. customthe solvent is removed under reduced pressure
8. customto give a brown mobile oil
9. customthe eluent evaporated under reduced pressure