反应详情

To a solution of 2-cyclopropyloxyimino-2-(5-tritylamino-1,2,4-thiadiazol-3-yl)acetic acid (syn isomer)(1 g) in anisole (2 ml) was added trifluoroacetic acid (8 ml) under ice-cooling. After stirring for 2 hours at ambient temperature, the mixture was concentrated in vacuo. The residue was poured into ice-water (50 ml). The mixture was adjusted to pH 7 with saturated aqueous solution of sodium bicarbonate and an insoluble material was filtered off. After washing with a mixture of ethyl acetate and tetrahydrofuran, the filtrate was adjusted to pH 2 with 6N hydrochloric acid and extracted with ethyl acetate. The extract was washed with saturated aqueous sodium chloride, dried over magnesium sulfate, concentrated in vacuo, and triturated with diisopropyl ether to give 2-(5-amino-1,2,4-thiadiazol-3-yl)-2-(cyclopropyloxyimino)acetic acid (syn isomer) as a crystal. The physical data of this compound were identical to those of the compound prepared in Preparation 48.

1. temperaturecooling
2. concentrationthe mixture was concentrated in vacuo
3. additionThe residue was poured into ice-water (50 ml)
4. filtrationan insoluble material was filtered off
5. washAfter washing with a mixture of ethyl acetate and tetrahydrofuran
6. extractionextracted with ethyl acetate
7. washThe extract was washed with saturated aqueous sodium chloride
8. dry with materialdried over magnesium sulfate
9. concentrationconcentrated in vacuo
10. customtriturated with diisopropyl ether