1,4-Dimethylpiperazine-2,3-dione → Bis(3-methylphenyl)ethane-1,2-dione

Participants

Reaction Steps

Mueller-Westerhoff9 and co-workers reported a simple, high-yield two-step synthesis of symmetrically substituted α-diones. The first step involves the preparation of 1,4-dimethylpiperazine-2,3-dione (13). Compound 13 was prepared in high yield from the reaction between N,N′-dimethylethylenediamine and diethyl oxalate in anhydrous diethyl ether at room temperature overnight. Second, compound 13 reacts with 2 equivalents of organolithium or Grignard compounds to form symmetrically-substituted α-diones after hydrolysis. 3,3′-Dimethylbenzil was prepared from the reaction between compound 13 and 2 equivalents of m-tolylmagnesium chloride in dry THF, followed by acidic workup in 35% yield (not optimized). Bis[1,2-di(3-methylphenyl)ethane-1,2-dithiolene]nickel (17) was then prepared by Schrauzer and Mayweg procedure as shown in FIG. 8.10

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