A new one-step method for the synthesis of the trimethyl ester of trans-aconitic acid

Abstract

The formation of even traces of (I) is not observed upon the reaction of methyl diazoacetate with dimethyl fumarate or dimethyl maleate or upon the trimerization of methyl diazoacetate without the pyridine. ZnCl 2 complex in the catalyst. A sample of 1o8 g (0.018 mole) N2CHCO2CH 3 in 5 ml CH2CI 2 was added dropwise to the catalytic system obtained by mixing 0.047 g (0.18 mmole) Cu(acac)2, 0.708 g (0.009 mole) pyridine, and 1.23 g (0.009 mole) ZnCI 2 in 20 ml CHzCI 2 at 26~ After 2 h, the reaction mixture was washed with water. The organic layer was dried over NazSO 4 and the solvent was evaporated. The residue was distilled in vacuum to give 0.91 g (-70%) (I), bp I05~ (I mm), nD z0 1.4629. The physicochemical indices of our sample of (I) were identical to those reported in the literature [i].