PROCESS FOR PREPARING ENTACAPONE SUBSTANTIALLY FREE OF Z-ISOMER, SYNTHESIS INTERMEDIATES THEREOF AND A NEW CRYSTALLINE FORM

摘要

The present invention relates to a new method for obtaining Entacapone substantially free of Z-isomer from 3,4-dihydroxy-5-Nitrobenzaldehyde and N,N-Dimethylcyanoacetamide, or directly from a mixture of (E)- and (Z)-isomers of Entacapone, by formation of organic or inorganic salts, specially piperidine and sodium ones. A new crystalline form G of Entacapone can be obtained from this method in a fast, efficient, and simple way and substantially free of Z-isomer. Another object of the invention is a pharmaceutical composition comprising it.