反应详情

(a) A mixture of S-methyl 2-(6-formamidopyridin-2-yl)thioglyoxylate (4.48 g.), methanol (20 ml.) and 1N aqueous solution of sodium hydroxide (20 ml.) was stirred for 50 minutes at ambient temperature to give a solution containing 2-(6-formamidopyridin-2-yl)glyoxylic acid. To the solution was added O-propylhydroxylamine hydrochloride (2.23 g.), and the mixture was stirred for 35 minutes at the same temperature. The reaction mixture was adjusted to pH 7 with hydrochloric acid and the methanol was distilled off. The remaining aqueous mixture was washed with ethyl acetate, and ethyl acetate was added thereto and then adjusted to pH 1 with 10% hydrochloric acid. The ethyl acetate layer was separated, washed with water, dried over magnesium sulfate, treated with activated charcoal and then the solvent was distilled off. Thus obtained product was washed with a mixture of diethyl ether and diisopropyl ether and then dried to give 2-(6-formamidopyridin-2-yl)-2-propoxyiminoacetic acid (syn isomer) (1.76 g.), mp. 140° to 142° C. (dec.).

1. customto give a solution
2. stirringthe mixture was stirred for 35 minutes at the same temperature
3. distillationthe methanol was distilled off
4. washThe remaining aqueous mixture was washed with ethyl acetate, and ethyl acetate
5. additionwas added
6. customThe ethyl acetate layer was separated
7. washwashed with water
8. dry with materialdried over magnesium sulfate
9. additiontreated with activated charcoal
10. distillationthe solvent was distilled off
11. washThus obtained product was washed with a mixture of diethyl ether and diisopropyl ether
12. customdried