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Generalized synthesis of [Gamma]-diketonesSudweeks, Walter Bentley 01 June 1970 (has links)
Various synthetic schemes were explored in order to develop a general synthesis of γ-diketones. The addition of organometallic reagents to several γ-dicarboxylic acids and γ-dinitrile compounds failed to produce any ketonic product, whereas addition to γ-diesters and γ-diacid chlorides gave only small amounts of the diketones in a mixture of products. A series of γ-diketones was prepared in low to moderate yields by way of the corresponding acetylenic glycols. These glycols were made by treating acetylenedimagnesium bromide with various aldehydes and then hydrogenation to the saturated γ-dialcohols. Oxidation of the alcohols produced diketones of type RCOCH_2CH_2COR where R = ethyl, isopropyl, t-butyl, n-propyl, n-hexyl, phenyl and cyclohexyl radicals. Good yields of γ-diketones were obtained by dialkylating 2,2'-ethylenebis(m-dithiane) followed by hydrolysis. Except for isopropyl iodide, the alkylation was successful only with primary alkyl halides. Diketones of the above type where R = ethyl, isopropyl, n-propyl, isobutyl, n-butyl, isoamyl, and benzyl radicals were prepared.
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Electrolytic synthesis of [gamma]-diketonesPahler, Leon F. 01 May 1972 (has links)
Four γ-diketones were synthesized by using a modification of the Kolbe electrolytic condensation of β-ketocarboxylic acids. [--see equation in thesis--] The following γ-diketones were synthesized in moderate yields: 2,5-hexanedione, 4,7-decanedione, 2,2,7,7-tetramethyl- 3,6-octanedione, and 1,4-diphenyl-1,4-butanedione (34, 39, 23, and 27, respectively). However, attempted preparation of the following γ-diketones failed: 3,4-dimethyl- 2,5-hexanedione, 3,3,4,4-tetramethyl-2,5-hexanedione, and 1,4-di(2-thienyl)-1,4-butanedione. Attempts to electrolytically condense α-alkyl and α, α-dialkyl substituted monocarboxylic acids have been reported and all attempts have ended in failure; similarly, the attempts to synthesize 3,4-dimethyl and 3,3,4,4-tetramethyl- 2,5-hexanedione from 2-methyl and 2,2-dimethyl-3- oxobutanoic acid, respectively, failed. The preparation of 1,4-di(2-thienyl)-l,4-butanedione failed because the product or side product was not soluble in the solvents tried and this resulted in precipitation of a non-conducting white product film on the electrodes, thus, preventing further electrolysis.
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