Potassium Carbonate → Dicyclohexylamine

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Reaction Steps

A solution of 4.2 g of 3-(4-chloro-3-sulfamoylbenzoylthio)-2-methylpropionyl chloride in 15 ml ofether is added dropwise to a mixture of 1.6 g of L-proline, aqueous 1 N potassium carbonate solution and 20 ml of ether under ice-cooling and stirring, and the resulting mixture is stirred at room temperature for 2 hours. The aqueous layer is then collected and acidic with dilute hydrochloric acid, and the separated oil is extracted with ethyl acetate. The extract is washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The residue is dissolved in acetonitrile and 2 g of dicylohexylamine is added. The oil thus obtained is washed several times with acetonitrile by decantation. The resulting crystals are recrystallized from isopropanol to give dicylohexylamine saltof 1-[3-(4-chloro-3-sulfamoylbenzoylthio)-2(S)-methylpropionyl]-L-proline as white crystalline powder, melting at 143°-146° C.

Provenance & Evidence