158693-04-0Relevant academic research and scientific papers
PROCESS FOR THE PREPARATION OF (E)-N,N-DIETHYL-2-CYANO-3(3,4-DIHYDROXY-5-NITRO-PHENYL)-ACRYLAMIDE IN STABLE POLYMORPHIC FORM AND INTERMEDIATES OF THE PROCESS
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Page/Page column 6-7, (2008/06/13)
The invention relates to a process for the preparation of pure E isomer of N1N- diethyl-2-cyano-3-(3,4-dihydrìxy-t5-nitro-phenyl)-acryIamide of formula (1 ) ( D in stable polymorphic form. According to the invention _ (a) (E)-N, N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy-5-nitro-phenyl)-acryl- amide is demethylated; or (b) (E)-N, N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy-phenyl)-acrylamide is nitrated, and the. resulting (E)-N-, N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy-5-nitro- phenyl)-acrylamide is demethylated; or - (c) vanillin is reacted with N.N-diethyl-cy.anoacetamide in the presence of a weak organic acid and of an amine compound used as catalysts, the resulting (E)- N,N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy-phenyl)-acrylamide is nitrated, and the resulting (E)-N, N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy-5-nitro-phenyl)-acrylamide is demethylated. The invention also relates to (E)-N, N-diethyl-2-cyano-3-(3-methoxy-4-hydroxy- phenyl)-acrylamide and (E)-N, N-diethyl-2-cyano-3-(3-rhethoxy-4-hydroxy-5-nitro- phenyl)-acrylamide and to their preparation.
IMPROVED PROCESS FOR THE PREPARATION OF ENTACAPONE
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Page/Page column 7-8, (2008/06/13)
The invention disclosed in this application relates to an improved process for the preparation of the Entacapone which comprises. (i)reacting 3-alkoxy- 4-hydroxy-5-nitrobenzadehyde with N,N-diethylaminocyanoactamide in the presence of mild acid catalyst and a solvent at a temperature in the range of 50-115 °C, to get the 3-O-alkylated (methyl or ethyl) Entacapone and treating with acid catalysts in the presence of organic base and solvents at temperature in the range of 20-60 °C to get Entacapone.
