- METHOD FOR SYNTHESIZING BETA-DICARBONYL COMPOUNDS
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A method for synthesizing beta-dicarbonyl compounds, particularly beta-diketones, from at least two carbonyl compounds, such as esters and ketones, in the presence of a strong base or a mixture of strong bases by Claisen condensation with a titer of greater than 95%. The method includes providing a synthesis reactor on which a separation column, provided with a condenser and with at least one microwave generator, is mounted; feeding a first carbonyl compound and the strong base into the synthesis reactor; heating the reactor and starting up the condenser; starting up the microwave generator(s); when the mixture is brought to a boil at total flux, feeding the second carbonyl compound into the reactor; and after a waiting time, stopping the reactor and acidifying and washing the reaction mixture.)
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Paragraph 0139; 0140; 0141; 0142; 0143
(2014/04/03)
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- Composition of lipids from sunflower pollen (Helianthus annuus)
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The contents of the pollen lipids of the sunflower Helianthus annuus are described. The major component is the seco-triterpene helianyl octanoate, followed by new β-diketones as second major group of compounds. They exhibit a shorter chain length and often other positions of the functional group compared to already known β-diketones. Of particular note are the 1-phenyl- β-diketones, not previously reported from nature. Further lipid classes present are related hydroxyketones and diols. Interestingly, new β- dioxoalkanoic acids are present in the extracts, which most likely are biogenetic precursors of the diketones. Additionally, we investigated the composition of the pollen coat which resembles the total extract, but lacks the dioxoalkanoic acids and certain estolides. (C) 2000 Elsevier Science Ltd.
- Schulz, Stefan,Arsene, Cristian,Tauber, Marianne,McNeil, Jeremy N.
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p. 325 - 336
(2007/10/03)
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- Process for the preparation of linear 1,3-diketones
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There is disclosed a process for the preparation of 1,3-diketones of formula I STR1 wherein R1 and R2 are each independently of the other C1 -C20 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, NO2, C1 -C4 alkyl and/or C1 -C4 alkoxy, C7 -C9 phenylalkyl or a radical of formula II wherein A is C1 -C12 alkylene, phenylene or phenylene which is substituted by halogen, hydroxy, NO2, C1 -C4 alkyl and/or C1 -C4 alkoxy, or is C1 -C12 alkylene which is substituted by hydroxy, halogen and/or alkoxy, X is oxygen or sulfur, and R4 is hydrogen, C1 -C18 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1 -C4 alkyl, NO2 and/or C1 -C4 alkoxy, or is C7 -C9 phenylalkyl, and R3 is hydrogen, C1 -C20 alkyl, phenyl or phenyl which is substituted by halogen, hydroxy, C1 -C4 alkyl, NO2 and/or C1 -C4 alkoxy, or is C7 -C9 phenylalkyl. The process comprises carrying out a Claisen condensation of a ketone of formula III STR2 and an ester of formula IV STR3 wherein R5 is C1 -C5 alkyl, phenyl or phenyl which is substituted by halogen, C1 -C4 alkyl or hydroxy, the reaction being carried out with the base used as catalyst, a hydride of an alkali metal or alkaline earth metal or an alcoholate of C1 -C5 alkali metal or C1 -C5 alkaline earth metal, in a mixture of dimethyl sulfoxide and at least one organic solvent which is inert under the reaction conditions.
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