反应详情

A mixture of 2-(3-chloro-4-hydroxyphenyl)glyoxylic acid (2.0 g.), O-t-butoxycarbonylmethylhydroxylamine (1.62 g.) and methanol (20 ml.) was adjusted to pH 5 to 6 by adding an 1 N methanol solution of sodium methoxide and stirred for 3 hours at ambient temperature. The reaction mixture was concentrated to dryness under reduced pressure and the residue was dissolved in an 1 N aqueous solution of sodium hydroxide to adjust to pH 7.0. The aqueous solution was washed with ether, adjusted to pH 2.0 with 10% hydrochloric acid under ice-cooling and extracted with ether. The extract was washed with water and dried over magnesium sulfate. The solution was concentrated to dryness under reduced pressure to give crystals of 2-t-butoxycarbonylmethoxyimino-2-(3-chloro-4-hydroxyphenyl)acetic acid (syn isomer) (2.6 g.), mp 116° to 118° C. (dec.).

1. concentrationThe reaction mixture was concentrated to dryness under reduced pressure
2. dissolutionthe residue was dissolved in an 1 N aqueous solution of sodium hydroxide
3. washThe aqueous solution was washed with ether
4. temperaturecooling
5. extractionextracted with ether
6. washThe extract was washed with water
7. dry with materialdried over magnesium sulfate
8. concentrationThe solution was concentrated to dryness under reduced pressure