反应详情

A suspension of (2-formamidothiazol-5-yl)glyoxylic acid (2.4 g) and methoxylamine hydrochloride (5.0 g) in water (144 ml) was adjusted to pH 4.9-5.0 with a saturated aqueous sodium bicarbonate and the mixture was stirred at ambient temperature for 4.7 hours. After water was added thereto in order to dissolve the insoluble material therein, the aqueous solution was concentrated to a volume of 100 ml. The precipitated material was collected by filtration, washed with water, followed by dissolving in a mixture of tetrahydrofuran and water. This solution was poured into a mixture of ethyl acetate and water, and the organic layer was separated out. After the aqueous solution was extracted with ethyl acetate, the combined ethyl acetate solution was washed with an aqueous sodium chloride and then dried over anhydrous magnesium sulfate. Removal of the solvent gave 2-(2-formamidothiazol-5-yl)-2-methoxyiminoacetic acid (anti isomer) (0.9 g), mp 159° C. (dec.). The filtrate obtained above was further concentrated to a volume of 70 ml, and the precipitated material was collected by filtration to recover the same product (0.23 g). Total yield: 1.13 g.

1. dissolutionin order to dissolve the insoluble material
2. concentrationthe aqueous solution was concentrated to a volume of 100 ml
3. filtrationThe precipitated material was collected by filtration
4. washwashed with water
5. dissolutionby dissolving in a mixture of tetrahydrofuran and water
6. additionThis solution was poured into a mixture of ethyl acetate and water
7. customthe organic layer was separated out
8. extractionAfter the aqueous solution was extracted with ethyl acetate
9. washthe combined ethyl acetate solution was washed with an aqueous sodium chloride
10. dry with materialdried over anhydrous magnesium sulfate
11. customRemoval of the solvent