反应详情

To a solution of 4-(5-methyl-1,3,4-oxadiazol-2-yl)benzaldehyde (5.12 g, 27.2 mmol) in anhydrous MeOH (27 mL) and anhydrous dioxane (27 mL) at −15 to −10° C. (bath temperature) was added several drops of a solution of KOH (7.6 g, 135.4 mmol) in MeOH (27 mL). Bromoform (3 mL, 34.4 mmol) was added, then the remaining KOH/MeOH solution was added over a period of 20 min. The mixture was stirred for 1 hr and the cold bath was removed. After stirring for 30 min, the reaction was put over an ice bath and allowed to warm slowly to room temperature overnight then concentrated to dryness. After dissolving in a minimum amount of H2O, the residue was acidified to pH 1 with 6 M HCl. The aqueous mixture was extracted with EtOAc several times with the addition of brine to the aqueous layer during extraction. The combined organics were washed with brine, dried over Na2SO4 and concentrated in vacuo to give 2-methoxy-2-(4-(5-methyl-1,3,4-oxadiazol-2-yl)phenyl)acetic acid as a semisolid (6.8 g, quantitative yield). The product was used without further purification.

1. customthe cold bath was removed
2. stirringAfter stirring for 30 min
3. customthe reaction was put over an ice bath
4. concentrationthen concentrated to dryness
5. dissolutionAfter dissolving in a minimum amount of H2O
6. extractionThe aqueous mixture was extracted with EtOAc several times with the addition of brine to the aqueous layer during extraction
7. washThe combined organics were washed with brine
8. dry with materialdried over Na2SO4
9. concentrationconcentrated in vacuo