反应详情

A mixture of ethyl 2-(2-aminothiazol-4-yl)-2-benzyloxyiminoacetate (syn isomer, 35 g.), 1 N aqueous sodium hydroxide (172 ml.), methanol (150 ml.) and tetrahydrofuran (150 ml.) was stirred at 35° to 40° C. for 9 hours and at room temperature for 12 hours. After adjusted the resultant solution to pH 6.5 with conc. hydrochloric acid, the solution was concentrated to about 2/3 volume of the initial. The concentrate was adjusted to pH 3.5 with conc. hydrochloric acid under ice cooling, and the precipitates were collected by filtration, washed with water and acetone in turn and then dried over phosphorus pentoxide under reduced pressure to give 2-(2-aminothiazol-4-yl)-2-benzyloxyiminoacetic acid (syn isomer, 11.5 g.).

1. concentrationthe solution was concentrated to about 2/3 volume of the initial
2. filtrationthe precipitates were collected by filtration
3. washwashed with water and acetone in turn
4. dry with materialdried over phosphorus pentoxide under reduced pressure