Stable polymorphs of (e)-n,n-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide

Stable polymorphs of (e)-n,n-diethyl-2-cyano-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide

The present invention relates to stable crystalline polymorphic forms C and D of (E)-N,N-diethyl-2-cyan-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide (Entacapone) and their preparation processes. (E)-Entacapone Form C is obtained by condensing 3,4-Dihydroxy-5-nitrobenzaldehyde and N,N-Diethylcyanoacetam...

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Bibliographische Detailangaben
Hauptverfasser: ZAKIR GAFOOR SHAIKH, RASHID ABDUL REHMAN KHAN, SIDDIQUI MOHAMMED JAWEED MUKARRAM, RAM PRASAD YADAV
Format: Patent
Sprache:eng
Schlagworte:
ACYCLIC OR CARBOCYCLIC COMPOUNDS
CHEMISTRY
METALLURGY
ORGANIC CHEMISTRY
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Beschreibung
Zusammenfassung:The present invention relates to stable crystalline polymorphic forms C and D of (E)-N,N-diethyl-2-cyan-3-(3,4-dihydroxy-5-nitrophenyl)acrylamide (Entacapone) and their preparation processes. (E)-Entacapone Form C is obtained by condensing 3,4-Dihydroxy-5-nitrobenzaldehyde and N,N-Diethylcyanoacetamide in presence of a base followed by addition of acetic acid after the reaction is over and crystallization step. (E)-Entacapone Form D is prepared from Entacapone Form C, Crystallographically pure (E)-Entacapone Form A or Crystallographically essentially pure From A. Polymorphic forms C and D of (E)-Entacapone are characterized by specific Infra Red (IR) and X-ray powder diffraction peak values.