反应详情

2-Hydroxy-6-methoxybenzaldehyde (16.875 g., 0.111 M), ethyl 5-bromopentanoate (23.25 g., 17.6 ml., 0.111 M), anhydrous potassium carbonate (16.5 g.), sodium iodide (0.675 g.) and 95% ethanol (150 ml.) were refluxed with stirring (16 hrs). The cooled reaction mixture was filtered and the solid washed well with ethanol. The filtrate was evaporated to dryness and the residue partitioned between ether and water. The ethereal layer was separated and washed with 2 N sodium hydroxide solution, water, dried (sodium sulphate) and evaporated. The residue was dissolved in 95% ethanol (300 ml.) and 0.66 N sodium hydroxide solution (450 ml.) and stirred at ambient temperature (4 hrs). The reaction mixture was evaporated to half volume and diluted with water. The mixture was extracted once with ether and the aqueous layer acidified with concentrated hydrochloric acid with cooling. The crystalline solid formed was filtered off and washed well with water. Recrystallisation from ethyl acetate-petrol gave 5-(2-formyl-3-methoxyphenoxy)pentanoic acid, m.p. 99°-101° C. (Found: C, 61.98; H, 6.58. C13H16O5 requires C, 61.89; H, 6.39%).

1. customThe cooled reaction mixture
2. filtrationwas filtered
3. washthe solid washed well with ethanol
4. customThe filtrate was evaporated to dryness
5. customthe residue partitioned between ether and water
6. customThe ethereal layer was separated
7. washwashed with 2 N sodium hydroxide solution, water
8. dry with materialdried (sodium sulphate)
9. customevaporated
10. dissolutionThe residue was dissolved in 95% ethanol (300 ml.)
11. stirring0.66 N sodium hydroxide solution (450 ml.) and stirred at ambient temperature (4 hrs)
12. customThe reaction mixture was evaporated to half volume
13. additiondiluted with water
14. extractionThe mixture was extracted once with ether
15. temperaturewith cooling
16. customThe crystalline solid formed
17. filtrationwas filtered off
18. washwashed well with water
19. customRecrystallisation from ethyl acetate-petrol