反应详情

Diisopropylethylamine (1.1 ml, 6.0 mmol) was added to a solution of terephthalic acid, monomethyl ester chloride (1.0 g, 5.0 mmol) and N-hydroxypentamidine (0.70 g, 6.0 mmol) in THF (8 mL). After stirring at ambient temperature for 1 hour, cesium carbonate (3.6 g, 11 mmol) was added and the reaction was stirred at 50° C. After stirring at 50° C. for 3.5 hours, the reaction was transferred to a separatory funnel with CH2Cl2/H2O. The aqueous layer was acidified with 1N HCl to pH 1 and extracted with CH2Cl2 (3×40 mL). The combined organic layers were dried (MgSO4) and concentrated in vacuo. Flash chromatography (silica, 50 mm dia, 10% EtOAc/hexane) afforded 1.2 g (93%) of methyl (3-butyl-1,2,4-oxadiazol-5-yl)benzoate.

1. stirringthe reaction was stirred at 50° C
2. stirringAfter stirring at 50° C. for 3.5 hours
3. extractionextracted with CH2Cl2 (3×40 mL)
4. dry with materialThe combined organic layers were dried (MgSO4)
5. concentrationconcentrated in vacuo