Method of purifying carbazole ester precursors of 6-chloro-alpha-meth yl-carbazole-2-acetic acid

• Main Authors: KEITH MICHAEL DEVRIES, DIANE MARIE RESCEK, PETER ROBERT ROSE, PHILIP DIETRICH HAMMEN, JOHN LLOYD TUCKER
• Format: Patent
• Language: English
• Published: 23.12.1999
• Edition: 6
• Subjects: CHEMISTRY; HETEROCYCLIC COMPOUNDS; METALLURGY; ORGANIC CHEMISTRY

A process of purifying a (6-chloro-2-carbazolyl)methyl-malonic acid di(C1 -C6 alkyl) ester of Formula (I): wherein Ra and Rb must be the same and are selected from the group consisting of C1 -C6 alkyl; comprises phase separating one or more impurities from said carbazole ester at least once wherein...