Hydrochloric Acid → 7-(alpha-Carboxythien-2-ylacetamido)-3-(1-methyl-1H-tetrazol-5-ylthio)methylceph-3-em-4-carboxylic acid disodium salt

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Reaction Steps

A suspension of thien-2-ylmalonic acid (0.93 g., 0.005 M) in water (25 ml.) was adjusted to pH 6.0 with saturated sodium bicarbonate solution, 7-amino-3-(1-methyl-1H-tetrazol-5-ylthio)methylceph-3-em-4-carboxylic acid was added, the solution again adjusted to 6.0, cooled to 0° and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (1.01 g., 0.005 M) added. The mixture was maintained at pH 5.8-6.0 with 6 N hydrochloric acid for two hours at room temperature then saturated sodium bicarbonate was added to pH 7.7 and the solution washed with ethyl acetate (50 ml.). The solution was acidified to pH 4.0, washed with ethyl acetate (2×25 ml.), acidified to pH 2.0 and extracted with ethyl acetate (2×50 ml.), The extracts were washed with water (25 ml.) and brine (25 ml.), dried over anhydrous magnesium sulphate, treated with 2 N sodium 2-ethylhexoate in methylisobutylketone (2 ml.), diluted with ether (200 ml.) and the precipitated disodium salt collected and dried in vacuo. Yield 1.16 g., 43.0%; U.V. spectrum (95% ethanol), λmax (ε=8.250). Paper chromatography (butanol/ethanol/water) showed a zone at Rf =0.05.

Provenance & Evidence