- SYNTHESIS OF 3-ALKYLCYCLOPENTANE-1,2-DIONES BY ACID-CATALYSED REARRANGEMENTS OF α-KETOGLYCOL DERIVATIVES
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Treatment of the adducts (3) derived from 1,2-bis(trimethylsilyloxy)cyclopentene and acetals, with p-toluene sulphonic acid in hot benzene is shown to lead to the corresponding 3-alkylcyclopentane-1,2-diones (4).
- Pattenden, Gerald,Teague, Simon
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p. 1403 - 1404
(2007/10/02)
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- 2-Methoxy-4-methyl-3-oxo-cyclopent-1-ene-1,4-dicarboxylic acid esters
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The disclosure relates to a novel process for the preparation of 3-alkyl-cyclopentane-1,2-diones and, in particular, to a novel process for the preparation of 3-methyl-cyclopentane-1,2-dione also known as Maple Lactone. The process comprises condensation of esters of glutaric acid and oxalic acid in a polar aprotic solvent in the presence of an alkali metal alkoxide to form 3,5-dicarboalkoxy-cyclopentane-1,2-dione dialkali metal salts, alkylating said salts with an alkylating agent to form a 2-alkoxy-3,5-dicarboalkoxy-5-alkyl-cyclopent-1-ene removing said solvent therefrom, and hydrolyzing the remainder with a mineral acid to form a 3-alkyl-cyclopentane-1,2-dione.
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