formula iv are novel compounds and accordingly represent a novel intermediate in the process according to the invention the cyclization and dehydrohalogenation step has to be carried out by contact of the starting compound with a base and in general mild bases are sufficient for example alkali metal and alkaline earth metal and ammonium hydroxides acetates carbonates bicarbonates and nitrogenous bases such as ammonia and alkyl substituted ammonias e g primary secondary and tertiary amines good results have also been obtained with alkali metal acetates carbonates and bicarbonates particularly preferred bases are ammonia and sodium acetate step a is preferably carried out in the absence of water and in the presence of a non aqueous solvent e g an alkanol such as methanol or ethanol or dimethyl formamide the latter solvent has been found to be particularly useful step b the decarboxylation step in the process according to the invention is preferably effected at a temperature in the range of from about 100 u00b0 to about 150 u00b0 c and it has been found that decarboxylation proceeds smoothly when the free acid the ammonium salt or the alkali metal salt is employed advantageously a polar aprotic solvent e g dimethyl formamide is used in the decarboxylation step generally step a and b may be carried out at ambient pressures although super atmospheric pressures may be employed if desired surprisingly it has been found that step a and step b can be.