Process for the manufacture of 1,4-dicyanonaphthalenes

A process for the manufacture of 1,4-dicyano-substituted bicyclic or tricyclic compounds of formula ##STR57## wherein R.sub.1 represents hydrogen, halogen, alkyl, alkoxy, carboxy, carbalkoxy, --CONR.sub.5 R.sub.6, wherein each of R.sub.5 and R.sub.6 independently represents hydrogen or alkyl, or together they complete a 5- or 6-membered heterocyclic ring, sulpho-, --SO.sub.2 NR.sub.5 R.sub.6, in which R.sub.5 and R.sub.6 are as defined hereinbefore, alkylsulphonyl, arylsulphonyl, cyano, nitro, or together with R.sub.2 completes a 6-membered aromatic ring or represents the methylenedioxy radical, R.sub.2 represents hydrogen, halogen, alkyl, alkoxy, carboxy, carbalkoxy, --CONR.sub.5 R.sub.6, wherein R.sub.5 and R.sub.6 are as defined hereinbefore, alkylsulphonyl, nitro, or together with R.sub.1 completes a 6-membered aromatic ring or represents the methylenedioxy radical, R.sub.3 represents hydrogen, halogen or alkyl and R.sub.4 represents hydrogen, halogen or alkyl, which process comprises reacting an o-xylene dicyanide of formua ##STR58## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are as defined hereinbefore, with glyoxal, in the presence of a base and a solvent, at temperatures below 50.degree. C.