反应详情

A solution of sodium (1.01 g.) in absolute methanol (10 ml.) was dropwise added over 15 minutes with stirring and ice-cooling to a solution of methyl 2-(isothiazol-4-yl)acetate (6.30 g.) and isopentyl nitrite (10.6 g.) in absolute methanol (63 ml.). The mixture was stirred for 30 minutes at the same temperature and for 3 hours at ambient temperature. The reaction mixture was concentrated and the residue was poured into a mixture of ethyl acetate (50 ml.) and water (50 ml.). The aqueous layer was separated and the ethyl acetate layer was extracted twice with 1 N aqueous solution of sodium hydroxide (20 ml. and 10 ml.). The extracts and the aqueous layer separated above were combined, adjusted to pH 1 with 10% hydrochloric acid and extracted twice with ethyl acetate (70 ml. and 50 ml.). The extracts were washed with a 5% aqueous solution of sodium bicarbonate and a saturated aqueous solution of sodium chloride and dried over magnesium sulfate. The solvent was distilled off under reduced pressure to give methyl 2-hydroxyimino-2-(isothiazol-4-yl)acetate (anti isomer) (4.55 g.), mp 110° to 112° C.

1. stirringThe mixture was stirred for 30 minutes at the same temperature and for 3 hours at ambient temperature
2. concentrationThe reaction mixture was concentrated
3. additionthe residue was poured into a mixture of ethyl acetate (50 ml.) and water (50 ml.)
4. customThe aqueous layer was separated
5. extractionthe ethyl acetate layer was extracted twice with 1 N aqueous solution of sodium hydroxide (20 ml. and 10 ml.)
6. customThe extracts and the aqueous layer separated
7. extractionextracted twice with ethyl acetate (70 ml. and 50 ml.)
8. washThe extracts were washed with a 5% aqueous solution of sodium bicarbonate
9. dry with materiala saturated aqueous solution of sodium chloride and dried over magnesium sulfate
10. distillationThe solvent was distilled off under reduced pressure