Method for purifying a fused pyrrolocarbazole derivative
View Patent ↗The present invention relates a method for purifying a fused pyrrolocarbazole compound known as 11-isobutyl-2-methyl-8-(2-pyrimidinylamino)-2,5,6,11,12,13-hexahydro-4Hindazolo[5,4-a]pyrrolo[3,4-c]carbazol-4-one using an acid complex thereof. The present invention also relates to a crystalline form of the acid complex.
1. A crystalline acid complex of formula (Ia):
wherein R represents methyl, characterized by an X-ray powder diffractogram comprising one or more of the following peaks: 5.19±0.2 degrees 2-Theta; 6.17±0.2 degrees 2-Theta; 6.44±0.2 degrees 2-Theta; 14.36±0.2 degrees 2-Theta; and 26.09±0.2 degrees 2-Theta.
2. A method for preparing the crystalline acid complex of formula (Ia) of claim 1 comprising:
i) contacting a compound of formula (I) with acetic acid
to form an acid complex of Formula (Ia); and
ii) crystallizing the resulting acid complex of Formula (Ia).
3. The method according to claim 2 optionally comprising contacting the acid complex of Formula (Ia) with a decolorizing agent.
4. The method according to claim 2 or 3 optionally comprising recovering the crystallized complex of formula (Ia).
5. The method according to claim 3 where in the decolorizing agent is a steam or chemically activated charcoal.
6. The method of claim 4 wherein the recovered crystalline complex of Formula (Ia) is at least about 92% pure.
7. The method of claim 4 wherein the recovered crystalline complex of Formula (Ia) is at least about 97% pure.