Aconic acid and related compounds: II. The reaction of aconic acid with diazomethane

Abstract From aconic acid with an excess of diazomethane a nitrogen‐containing compound is formed. The structure was established to be methyl 3,4‐(4′,5′‐Δ1‐pyrazolino) aconate. Heating of this compound resulted in the splitting off of a molecule of nitrogen and the formation of a methyl‐substituted aconic acid ester hitherto unknown in the literature.