Dicyclohexylcarbodiimide → 7-[[(1-Pyrryl)acetyl]amino]-3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, tert-butyl ester

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Reaction Steps

(1-Pyrryl)acetic (0.03m) is added to water, the pH of which is adjusted to about 6.5 by the addition of sodium bicarbonate. This solution is cooled in an ice bath and to it is added 3-[[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methyl]-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid tert-butyl ester (0.1 m) (7-ATDCA) followed by N, N'-dicyclohexylcarbodiimide (0.01m) in cold dioxane. The mole ratio of (1-pyrryl) acetic acid/7-ATDCA/carbodiimide is 3/1/1. After standing overnight at ice bath temperature, the reaction mixture is filtered to remove solids. The filtrate is evaporated to dryness, the solids taken up in ethyl acetate, dried over magnesium sulfate and filtered. The ethyl acetate solution is concentrated and then treated with hexane. The title compound precipitates from solution, and is recovered.

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