Abstract: A process for the production of esters of the general formula ##STR1## in which R.sup.1 signifies methyl or ethyl and R.sup.2 and R.sup.3, independently from one another, signify C.sub.1-4 -alkyl, is described.The process is characterized in subjecting a diketo ester of the formula ##STR2## in which R.sup.1 to R.sup.3 have the above significances; and X is chlorine or bromine, preferably chlorine, and to a dehydrohalogenation process.The compounds I are known odorants.

Abstract: A process for the manufacture of esters of formula ##STR1## in which R.sup.1 signifies methyl or ethyl and R.sup.2 and R.sup.3, independently from one another, signify hydrogen or C.sub.1-4 -alkyl,is described. The process comprises treating a diketo ester of the formula ##STR2## in which R.sup.1 to R.sup.3 have the above significances, with the combination ofCuX.sub.2 and MeX.sub.n IIIin which Me signifies an alkali metal or alkaline earth metal ion, X signifies halogen and n corresponds to the valency of the metal ion.Compounds I are known odorants.The reaction involved is thus an aromatization of the starting material.