Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1999-04-15
2000-01-11
Stockton, Laura L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D20982, C07D20984
Patent
active
060138084
ABSTRACT:
A process of purifying a (6-chloro-2-carbazolyl)methyl-malonic acid di(C.sub.1 -C.sub.6 alkyl) ester of Formula (I): ##STR1## wherein R.sub.a and R.sub.b must be the same and are selected from the group consisting of C.sub.1 -C.sub.6 alkyl; comprises phase separating one or more impurities from said carbazole ester at least once wherein the solvent used to carry out said phase separation is acetic acid. In a preferred embodiment said acetic acid is glacial acetic acid which is maintained at a temperature of from about 30.degree. to about 110.degree.0 C. and said carbazole ester is obtained in a purity of at least 99.90% by weight, so that the amount of impurities present therein is 0.10% or less by weight. In a more preferred embodiment of said process, said temperature is from about 50.degree. to about 70.degree. C., and said phase separation is carried out only once.
REFERENCES:
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patent: 4264500 (1981-04-01), Zwamlen
Reymond et al., Heterocycles (1982), 19(12), 2345-7, 1982.
Ross et al., J. Pharm. Sci. (1984), 73(9), 1211-15, 1984.
DeVries Keith M.
Hammen Philip D.
Rescek Diane M.
Rose Peter R.
Tucker John L.
Ginsburg Paul H.
Pfizer Inc.
Richardson Peter C.
Speer Raymond M.
Stockton Laura L.
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