REMOVAL OF PALLADIUM FROM ORGANIC-REACTION MIXTURES BY TRIMERCAPTOTRIAZINE

In an effort to remove residual palladium from a drug candidate prepar ed by palladium-catalyzed indolization, many treatments were examined. The most effective treatment was to precipitate palladium from soluti on using 2,4,6-trimercapto-s-triazine (TMT), which reduced palladium l evels from 600-650 ppm to 20-60 ppm in an isolated indole intermediate . Subsequent crystallizations routinely afforded active pharmaceutical ingredient with <1 ppm of palladium. TMT treatment should prove usefu l to reduce the concentration of residual palladium in other reactions .