The Preparation and Reactions of Acetopyruvic Acid (α,γ-Diketo-n-valeric Acid)^*

Abstract

In 1937 Krebs and Johnson1 proposed that acetopyruvic acid is an intermediate in the biochemical synthesis of acetoacetic acid from acetic and pyruvic acids. This compound has been previously described by Mumm and Bergell,2 who also prepared several derivatives. However, the results reported by these workers seemed to indicate that this compound spontaneously undergoes unknown reactions in aqueous solution.Since knowledge of such reactions would be of great importance in a critical evaluation of its possible biochemical role, further study of its preparation and properties seemed required. In routine practice it was also found that the synthesis, as described by Mumm and Bergell, gave irregular results and that the procedure could be improved materially.In this report some details concerning the synthesis, two unreported derivatives, stability, acid behavior, and some data on the oxidation mechanisms of acetopyruvic acid are described.I. Synthesis and Properties.-Difficulties encountered with the Mumm and Bergell procedure for this synthesis led to the trial of sodium methylate in the synthesis of the sodio-ester compound. Freri3 has shown that the methyl ester is formed in this condensation when sodium methylate is used as condensing agent, and the methyl ester was thought to have the advantage of being more rapidly hydrolyzed than the ethyl ester. However, it was soon realized that the difficulties in the preparation of the free acid from the sodio-ester arose from the fact that the sodium salt of the acid produced was almost as rapidly hydrolyzed as was the ester itself under the conditions of the Mtunm and Bergell synthesis. The reactions involved are schematized in reactions (1) and (2).CH8COCH==C(ONa)COOC2H6 + NaOH -> CHsCOCH=C(ONa)COONa + C2H6OH (1) CH3COCH-C (ON a) COONa + NaOH ->-CHsCOCHs + (COONah (2)In the Mumm and Bergell synthesis reaction * Supported in part by the Wisconsin Alumni Research Foundation.

Acetoacetate decarboxylase. Reaction with acetopyruvate

“…The oxalic acid (6.5 mg, 1.35 mCi/mmoles) was diluted with about 400 mg of unlabeled oxalic acid dihydrate (Merck) and converted to diethyl oxalate (yield, 300 mg) according to the method of Marvel and Dreger (1932). The ester was further diluted with 100 mg of unlabeled diethyl oxalate and condensed with acetone according to Lehninger and Witzemann (1942). The hydrolysis of the ester was inefficient: after sublimation and recrystallization of the acid (from carbon tetrachloride), only 24 mg of acid, mp 99°( lit.…”

Microbial metabolism of the pyridine ring. The metabolism of pyridine-3,4-diol (3,4-dihydroxypyridine) by Agrobacterium sp

“…The corresponding 2,4-dioxohexanoate'and 2,4-dioxoheptanoate esters were extracted with benzene and purified by distillation under reduced pressure. The free acids of all three esters were prepared by saponification with 1 or 2 equivalents of NaOH, followed by acidification and extraction into diethyl ether (Lehninger &Witzemann, 1942). The solid residues left after evaporation of the ether were purified by recrystallization from carbon tetrachloride and vacuum sublimation [60-80'C; 1.33kN/m2 (10mmHg)].…”

Characterization and substrate specificity of fumarylacetoacetate fumarylhydrolase

“…(24). These esters were then hydrolyzed to the free acids by the method of Lehninger and Witzemann (23). Propionopyruvic acid was further purified by vacuum sublimation (mp 82-83 "C, Anul.…”