反应详情

p-Cyanobenoic acid methyl ester (5.0 g, 31 mmol) was converted into the corresponding oxadiazolinone as described for the synthesis of compound 3. The crude product (4.6 g, 20.9 mmol) was dissolved in a mixture of THF (50 mL) and MeOH (50 mL). H2O (50 mL) was added, which gave a suspension, followed by 4 N aq. NaOH (10 mL). After 6 h the organic solvents were removed by distillation under reduced pressure. The aq. layer was extracted with EtOAc/toluene (1/2, v/v), acidified with 2 N hydrochloric acid and the precipitate was filtered off. The crude product was dried at 40° C. under reduced pressure to give 4.2 g (97%) of compound 60. ESI-MS: 207 [M+H]+.

1. customwhich gave a suspension
2. customAfter 6 h the organic solvents were removed by distillation under reduced pressure
3. extractionThe aq. layer was extracted with EtOAc/toluene (1/2
4. filtrationthe precipitate was filtered off
5. dry with materialThe crude product was dried at 40° C. under reduced pressure