4-((2-Carboxy-2-(1,3-dithiol-2-ylidene)acetyl)amino)-5-(dipropylamino)-5-oxopentanoic acid → 5-(Dipropylamino)-4-((2-(1,3-dithiol-2-ylidene)acetyl)amino)-5-oxopentanoic acid

Participants

Reaction Conditions

Reaction Steps

Dioxane (1.5 l) and activated carbon (10 g) were added to the 4-((2-carboxy-2-(1,3-dithiol-2-ylidene)acetyl)amino)-5-(dipropylamino)-5-oxopentanoic acid (6) obtained in Synthesis Example 4. The resulting mixture was stirred at 50° C. for 30 minutes. The activated carbon was filtered off, and the solvent was removed from the filtrate under reduced pressure. Acetone was added to the thus-obtained residue. The resulting crystals were collected by filtration, washed with water, acetone and diethyl ether, and then dried at 60° C. for 8 hours under reduced pressure, whereby 5-(dipropylamino)-4-((2-(1,3-dithiol-2-ylidene)acetyl)amino)-5-oxopentanoic acid (1) (67 g, yield: 72% (based on the compound (5)) was obtained as pale yellow crystals.

Provenance & Evidence