Hydrochloric Acid → Pepstatin glutamic acid

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Reaction Steps

Into 8 cm3 of a mixture of dimethylformamide and dimethylsulfoxide (3-1 by volume), 130 mg of pepstatin and 120 mg of the hydrochloride of tertiobutyl diester of glutamic acid are added. Then 180 mg of BOP and 45 mg of triethylamine are added. After 72 hours of stirring, 15 cm3 of distilled water are added. The precipitate is drained and washed with 15 cm3 of ethyl ether. The product is redissolved in 30 cm3 of methanol. The insoluble residue is separated by filtration and the filtrate is evaporated. Then 10 cm3 of a mixture of methylene chloride-trifluoroacetic acid (1:1 by volume) are added, then it is allowed to stand for 30 minutes at a temperature close to 20° C. The mixture is concentrated almost to dryness. Ether is then added. The precipitate formed is separated by filtration and then washed with ether. After drying, 130 mg of pepstatin-glutamic acid are obtained whose characteristics are as follows:

Provenance & Evidence