Sodium Bicarbonate → 2-(2-Formamidothiazol-4-yl)-2-(4-bromo-3-hydroxybenzyloxyimino)acetic acid

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Reaction Steps

The solution of 4-bromo-3-hydroxybenzyloxyamine phosphate (17.4 g.) in water (200 ml.) and ethanol (200 ml.) was stirred at room temperature and adjusted to pH 7.0 with sodium bicarbonate. 2-(2-Formamidothiazol-4-yl)glyoxylic acid (10.0 g.) was added to the solution and the resulting suspension was adjusted to pH 4.0 to 4.5. After stirring the solution at room temperature for 2 hours, ethanol was removed from the resultant solution in vacuo. Ethyl acetate was added to aqueous residue and adjusted to pH 2.5 with 10% hydrochloric acid. The ethyl acetate layer was separated, washed with water and dried over magnesium sulfate. The solution was concentrated in vacuo to give 2-(2-formamidothiazol-4-yl)-2-(4-bromo-3-hydroxybenzyloxyimino)acetic acid (syn isomer, 14.8 g.).

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