Process for the preparation of monoesters or diesters of 9,10-endoethano-9,10-dihydroanthracene-11, 11-dicarboxylic acid, novel monoesters or diesters prepared by this process anduse thereof for the preparation of symmetrical or asymmetrical methylidenemalonates

Abstract From the Canadian patent

The invention relates to novel monoesters and diesters of 9,10-endoethano-9,10-dihydroanthracene- 11,11-dicarboxylic acid. These novel monoesters and diestera correspond to the following structural chemical formula (II): (II), in which R1 and R2 are identical or different and can represent H, an alkali metal or alkaline earth metal atom, a linear or branched alkyl group having from 1 to 6 carbon atoms, an alicyclic group having from 3 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, defined in their cis or trans variety or an alkynyl group having from 2 to 6 carbon atoms the said groups optionally being substituted by one or more functional groups such as ether, epoxide …