p-Toluenesulfonic acid monohydrate → HCID 53704037, compound

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Reaction Steps

A mixture of 2-benzhydryloxycarbonyl-7-[2-methoxyimino-2-(tritylamino-thiazol-4-yl)-acetamido]-8-oxo-3-(2-tosyloxy-vinyl)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene (syn isomer, E-form) (0.494 g), acetone (20 cc) and p-toluenesulphonic acid hydrate (10 mg) is heated under reflux for 20 hours. It is then concentrated to dryness under 20 mm Hg at 20° C., the residue is taken up in ethyl acetate (30 cc) and a 5% strength sodium bicarbonate solution (20 cc), and the organic phase is decanted, dried over sodium sulphate, filtered and concentrated to dryness under 20 mm Hg at 20° C. The residue is chromatographed on a column (column diameter: 3 cm, height: 27 cm) of Merck silica gel (0.06-0.2 mm) (50 g). Elution is carried out with ethyl acetate (0.4 liter), 20 cc fractions being collected. Fractions 8 to 10 are a mixture of the starting material and of the expected product; fractions 11 to 17 are concentrated to dryness under 20 mm Hg at 20° C. 7-[2-(2-amino-thiazol-4-yl)-2-methoxyimino-acetamido]-2-benzhydryloxycarbonyl-8-oxo-3-(2-tosyloxy-vinyl)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene (syn isomer, E-form) (0.15 g) is obtained in the form of a cream-coloured solid.

Provenance & Evidence